7. GENERAL PRECAUTIONS
Mistakes in operation extremely dangerous.
Read all the Operation and Maintenance Manual care-
fully BEFORE operating the machine.
1. Before carrying out any greasing or repairs, read
all the precautions written on the decals which
are suck on the machine.
2. When carrying out any operation, always wear
safety shoes and helmet. Do not wear loose work
clothes, or clothes with buttons missing.
. Always wear safety glasses when hitting parts
with a hammer.
. Always wear safety glasses when grinding
parts with a grinder, etc.
3. If welding repairs are needed, always have a
trained, experienced welder carry out the work.
When carrying out welding work, always wear
welding gloves, apron, glasses, cap and other
clothes suited for welding work.
4. When carrying out any operation with two or more
workers, always agree on the operating procedure
before starting. Always inform your fellow workers
before starting any step of the operation. Before
starting work, hang UNDER REPAIR signs on
the controls in the operator's compartment.
5. Keep all tools in good condition and learn the cor-
rect way to use them.
6. Decide a place in the repair workshop to keep
tools and removed parts. Always keep the tools
and parts in their correct places. Always keep
the work area clean and make sure that there is
no dirt or oil on the floor.
Smoke only in the areas provided for smoking.
Never smoke while working.
PREPARATIONS FOR WORK
7. Before adding or making any repairs, park the ma-
chine on hard, level ground, and block the wheels
to prevent the machine from moving.
8. Before starting work, lower outrigger, bucket or
any other work equipment to the ground. If this
is not possible, use blocks to prevent the work
equipment from falling down. In addition, be sure
to lock all the control levers and hang warning
sign on them.
9. When disassembling or assembling, support the
machine with blocks, jacks or stands before start-
ing work.
10. Remove all mud and oil from the steps or other
places used to get on and off the machine. Always
use the handrails, ladders or steps when getting
on or off the machine.
Never jump on or off the machine.
If it is impossible to use the handrails, ladders or
steps, use a stand to provide safe footing.
PRECAUTIONS DURING WORK
11. When removing the oil filler cap, drain plug or hy-
draulic pressure measuring plugs, loosen them
slowly to prevent the oil from spurting out.
Before disconnecting or removing components of
the hydraulic circuit and engine cooling circuit,
first remove the pressure completely from the cir-
cuit.
12. The water and oil in the circuits are not hot when
the engine in stopped, so be careful not to get
burned.
Wait for the oil water to cool before carrying out
any work on the cooling water circuits.
00-3WB70A-1
IMPORTANT SAFETY NOTICE
Proper service and repair is extremely important for the safe operation of your machine.
The service and repair techniques recommended by Komatsu Utility and describe in this manual are
both effective and safe methods of operation. Some of these operations require the use of tools specially
designed by Komatsu Utility for the purpose.
To prevent injury to workers, the symbols and are used to mark safety precautions in this man-
ual. The cautions accompanying these symbols should always be carefully followed. If any danger arises
or may possibly arise, first consider safety, and take necessary steps to face.
SAFETY
8. 13. Before starting work, remove the leads from the
battery. Always remove the lead from the negative
( ± ) terminal first.
14. When raising heavy components, use a hoist or
crane. Check that the wire rope, chains and hooks
are free from damage.
Always use lifting equipment which has ample ca-
pacity. Install the lifting equipment at the correct
places.
Use a hoist or crane and operate slowly to prevent
the component from hitting any other part.
Do not work with any part still raised by the hoist
or crane.
15. When removing covers which are under internal
pressure or under pressure from a spring, always
leave two bolts in position on opposite sides.
Slowly release the pressure, then slowly loosen
the bolts to remove.
16. When removing components, be careful not to
break or damage the wiring.
Damage wiring may cause electrical fires.
17. When removing piping, stop the fuel or oil from
spilling out. If any fuel or oil drips on to the floor,
wipe it up immediately.
Fuel or oil on the floor can cause you to slip, or
can even start fires.
18. As a general rule, do not use gasoline to wash
parts. In particular, use only the minimum of gaso-
line when washing electrical parts.
19. Be sure to assemble all parts again in their origi-
nal places. Replace any damage parts with new
parts.
. When installing hoses and wires, be sure that
they will not be damaged by conctat with other
parts when the machine is being operated.
20. When installing high pressure hoses, make sure
that they are not twisted. Damaged tubes are dan-
gerous, so be extremely careful when installing
tubes for high pressure circuits. Also, check that
connecting parts are correctly tightened.
21. When assembling or installing parts, always use
specified tightening torques.
When installing the parts which vibrate violently or
rotate at high speed, be particulary careful to
check that they are correctly installed.
22. When aligning two holes, never insert your fingers
or hand.
23. When measuring hydraulic pressure, check that
the measuring tool is correctly assembled before
taking any measurement.
24. Take sure when removing or installing tracks of in
particular rubber tracks. When removing the
track, the track separates suddenly, so never let
anyone stand at either end of the wheel.
00-4 WB70A-1
9. 00-5WB70A-1
FOREWORD
This shop manual has been prepared as an aid to improve the quality of repairs by giving the operator an ac-
curate understanding of the product and by showing him the correct way to perform repairs and make judgements.
Make sure you understand the contents of this manual and use it to full effect at every opportunity.
This shop manual mainly contains the necessary technical information for operations performed in a service
workshop.
The manual is divided into chapters on each main group of components; these chapters are further divided into
the following sections.
STRUCTURE AND FUNCTION
This section explains the structure and function of each component. It serves not only to give an under-
standing of the structure, but also serves as reference material for troubleshooting.
TESTING AND ADJUSTING
This sections explains checks to be made before and after performing repairs, as well as adjustments to be
made at completion of the checks and repairs.
Troubleshooting charts correlating «Problems» to «Causes» are also included in this section.
DISASSEMBLY AND ASSEMBLY
This section explains the order to be followed when removing, installing, disassembling or assembling
each component, as well as precautions to be taken for these operations.
MAINTENANCE STANDARD
This section gives the judgement standards when inspecting disassembled parts.
NOTICE
The specifications contained in this shop manual are subject to change at any time and without any
notice.
Contact your Komatsu Utility distributor for the latest information.
10. VOLUMES
Shop manual are issued as a guide to carry out re-
pairs. These various volumes are designed to avoid
duplicating the same information.
DISTRIBUTION AND UPDATING
Any additions, amendments or other changes will
be sent to Komatsu Utility distributors.
Get the most up-to-date information before you start
any work.
FILING METHOD
1. See the page number on the bottom of the page.
File the pages in correct order.
2. Following examples show you how to read the
page number.
Example
3. Additional pages: additional pages are indicated
by a hyphen (-) and number after the page num-
ber.
Fle as in the example.
Example:
10-4
10-4-1
10-4-2
10-5
] Added pages
REVISED EDITION MARK
(1 2 3 ....)
When a manual is revised, an edition mark is re-
corded on the bottom outside corner of the pages.
REVISIONS
Revised pages are shown on the LIST OF RE-
VISED PAGES between the title page and SAFETY
page.
SYMBOLS
In order to make the shop manual greatly chelpful,
important points about safety and quality are marked
with the following symbols.
Symbol Item Remarks
Safety
Special safety precautions are ne-
cessary when performing the
work.
Extra special safety precautions
are necessary when performing
the work because it is under inter-
nal pressure.
Caution
Special technical precautions or
other precautions for preserving
standards are necessary when
performing the work.
Weight
Weight of parts or systems.
Caution necessary when selecting
hoisting wire, or when working
posture is important, etc.
Tightening
torque
Parts that require special attention
for the tightening torque during as-
sembly.
Coat
Parts to be coated with adhesives
and lubricants etc.
Oil,
water
Places where oil, water or fuel
must be added, and their quantity.
Drain
Places where oil or water must be
drained, and quantity to be
drained.
HOW TO READ THE SHOP MANUAL
HOW TO READ THE SHOP MANUAL
00-6 WB70A-1
Item number (10. Structure and
Function)
Consecutive page number for each
item.
10 - 3
11. Heavy parts (25 kg or more) must be lifted
with a hoist etc. In the Disassembly and As-
sembly section, every part weighing 25 kg or
more is clearly indicated with the symbol
1. If a part cannot be smoothly removed from the
machine by hoisting, the following checks should
be made:
. Check for removal of all bolts fastening the part
to the relative parts.
. Check for any part causing interference with
the part to be removed.
2. Wire ropes
1) Use adequate ropes depending on the weight
of parts to be hoisted, referring to the table be-
low:
WIRE ROPES
(Standard «S» or «Z» twist ropes
without galvanizing)
Rope diameter (mm) Allowable load (tons)
10
11.2
12.5
14
16
18
20
22.4
30
40
50
60
1.0
1.4
1.6
2.2
2.8
3.6
4.4
5.6
10.0
18.0
28.0
40.0
The allowable load value is estimated to be
one-sixth or one-seventh of the breaking
strength of the rope used.
2) Sling wire ropes from the middle portion of the
hook. Slinging near the edge of the hook may
cause the rope to slip off the hook during hoist-
ing, and a serious accident can result.
Hooks have maximum strenght at the middle por-
tion.
3) Do not sling a heavy load with one rope alone,
but sling with two or more ropes symmetrically
wound on to the load.
Slinging with one rope may cause turning of
the load during hoisting, untwisting of the
rope, or slipping of the rope from its original
winding position on the load, which can
cause dangerous accidents.
4) Do not sling a heavy load with ropes forming a
wide hanging angle from the hook.
When hoisting a load with two or more ropes,
the force subjected to each rope will increase
with the hanging angles.
The table below shows the variation of allow-
able load (kg) when hoisting is made with two
ropes, each of which is allowed to sling up to
1000 kg vertically, at various handing angles.
When two ropes sling a load vertically, up to
2000 kg of total weight can be suspended.
This weight becomes 1000 kg when two ropes
make a 120ë hanging angle.
On the other hand, two ropes are subjected to
an excessive force as large as 4000 kg if they
sling a 2000 kg load at a lifting angle of 150ë.
HOISTING INSTRUCTIONS
HOISTING INSTRUCTIONS
00-7WB70A-1
12. STANDARD TIGHTENING TORQUE
STANDARD TIGHTENING TORQUE
00-8 WB70A-1
The following charts give the standard tightening torques of bolts and nuts. Exceptions are given in sections of «Dis-
assembly and Assembly».
1. STANDARD TIGHTENING TORQUE OF BOLTS AND NUT
Thread diameter
of bolts
(mm)
Pitch of
bolts
(mm)
Width across flat
(mm)
kgm Nm kgm Nm
6
8
10
12
14
1
1.25
1.5
1.75
2
10
13
17
19
22
5
6
8
10
12
0.96w0.1
2.3w0.2
4.6w0.5
7.8w0.8
12.5w1
9.5w1
23w2
45w4.9
77w8
122w13
1.3w0.15
3.2w0.3
6.5w0.6
11w1
17.5w2
13.5w1.5
32.2w3.5
63w6.5
108w11
172w18
16
18
20
22
24
2
2.5
2.5
2.5
3
24
27
30
32
36
14
14
17
17
19
19.5w2
27w3
38w4
52w6
66w7
191w21
262w28
372w40
511w57
644w70
27w3
37w4
53w6
73w8
92w10
268w29
366w36
524w57
719w80
905w98
27
30
33
36
39
3
3.5
3.5
4
4
41
46
50
55
60
19
22
24
27
Ð
96w10
131w14
177w20
230w25
295w33
945w100
1287w140
1740w200
2250w250
2900w330
135w15
184w20
250w27
320w35
410w45
1329w140
1810w190
2455w270
3150w350
4050w450
This torque table does not apply to bolts or nuts which have to fasten nylon or other parts non-ferrous metal washer.
, Nm (Newton meter): 1 Nm = 0.102 kgm
13. STANDARD TIGHTENING TORQUE
00-9WB70A-1
2. TIGHTENING TORQUE FOR NUTS OF FLARED
Use these torques for nut part of flared.
Thread diameter
of nut part
(mm)
Width across flats
of nut part
(mm)
TIGHTENING TORQUE
kgm Nm
1/2" - 20
9/16" - 18
3/4" - 16
7/8" - 14
1.1
/16
"
- 12
1.5
/16
"
- 12
1.5
/8
"
- 12
22
33
17
17
22
27
32
38
50
27
41
2.6w0.5
4w0.5
6.7w2
8w2
9.7w3
17w3
20w5
8w2
20w5
25.5w4.9
39.2w4.9
65.7w19.6
78.5w19.6
95.15w29.4
166.7w29.4
196.2w49
78.5w19.6
196.2w49
Thread diameter
of nut part
(mm)
Width across flats
of nut part
(mm)
TIGHTENING TORQUE
kgm Nm
9/16" - 18
11/16" - 16
13/16" - 16
1" - 14
1.3
/16
"
- 12
1.7
/16
"
- 12
1.11
/16
"
- 12
2" - 12
17
22
24
30
36
41
50
57
2.3 ± 2.5
3.4 ± 3.9
5.2 ± 5.8
8.2 ± 9.2
12.2 ± 13.3
15.3 ± 17.3
18.4 ± 20.4
20.4 ± 24.4
23 ± 25
33 ± 38
51 ± 57
80 ± 90
120 ± 130
150 ± 170
180 ± 200
200 ± 240
Superficie di tenutaSealing surface
14. COATING MATERIALS
00-10 WB70A-1
COATING MATERIALS
The recommended coating materials prescribed in Komatsu Utility Shop Manuals are listed below:
Nomenclature Code Applications
Adhesives
ASL800010 Used to apply rubber pads, rubber gaskets and cork plugs.
ASL800020
Used to apply resin, rubber, metallic and non-metalic parts when a fast, strong seal
is needed.
Loctite 222 Used for low resistance locking of screws, check nuts and adjustment nuts.
Loctite 242
To prevent the loosening of bolts, nuts and plugs and the leakage of oil. Used for
medium resistance locking of screws and nuts of every type, and for locking keys
and bearings.
Loctite 262 Used for high resistant of threaded parts that can be removed with normal tools.
Loctite 270 Used for high resistant locking and for sealing threaded parts, bolts and stud bolts.
Loctite 542 Used for sealing the union threads for hydraulic tubes.
Loctite 573
Used for sealing rather exact plane surfaces when the option of possible future
dismantling is required.
Loctite 601
Used for high resistant locking of mechanical components that can be removed
only after heating
Loctite 675
Used to lock cylindrical couplings and for the permanent locking of threaded parts,
and also to lock shafts to bearings, gears, pulleys, pins, bushings, etc.
Gasket sealant
ASL800060
Used by itself to seal grease fittings, tapered screw fittings and tapered screw fit-
tings in hydraulic circuits of less than 50 mm in diameter.
Loctite 510
Used by itself on mounting flat surface
(Clearance between surfaces within 0.2 mm)
Loctite 518
Used by itself on mounting flat surface
(Clearance between surfaces within 0.5 mm)
Antifriction compound
(Lubricant including
Molybdenum disulfide)
ASL800040
Applied to bearings and taper shaft to facilitate press-fitting and to prevent stick-
ing, burning or rusting.
Grease
(Lithium grease) ASL800050
Applied to bearings, sliding parts and oil seals for lubrication, rust prevention and
facilitation of assembling work.
Vaseline ± Used for protecting battery electrode terminals from corrosion.
15. ELECTRIC WIRE CODE
ELECTRIC WIRE CODE
00-11WB70A-1
In the wiring diagrams. various colours and symbols are employed to indicate the thickness of wires.
This wire code table will help you understand WIRING DIAGRAMS.
Example: R -N 1.5 indicates a cable having a nominal number 1.5 and red coating with black stripe.
CLASSIFICATION BY THICKNESS
Nominal
number
Copper wire
Cable O.D.
(mm)
Current rating
(A)
Applicable circuitNumber
strands
ù of strands
(mm)
Cross section
(mm2
)
0.35 11 0.20 0.35 1.55 3.5 Proximity sensor
0.5 16 0.20 0.50 2.40 6 Instruments
0.8 11 0.30 0.78 2.80 8 Instruments, transmitter
1 14 0.30 0.99 2.80 11 Light switch - signal etc.
1.5 21 0.30 1.48 3.35 14
Working beam - solenoid valve
etc.
2,5 35 0.30 2.47 3.80 20
Control panel - Ignition switch
etc.
4 56 0.30 3.95 4.60 28 Alternator - preheating etc.
6 84 0.30 5.93 5.20 37 Starter motor fuses
50 399 0.40 50.11 14 160 Ground - starter motor
CLASSIFICATION BY COLOUR AND CODE
Primary Auxiliary
Code A A-B A/B A-G A/G A-N A/N A-R A/R A-V A/V
Colour Light blue Light blue-White Light blue-Yellow Light blue-Black Light blue-Red Light blue-Green
Code B B-G B/G B-L B/L B-N B/N B-R B/R ± ±
Colour White White-Yellow White-Blue White-Black White-Red ±
Code C C-B C/B C-N C/N C-V C/V ± ± ± ±
Colour Orange Orange-White Orange-Black Orange-Green ± ±
Code G G-N G/N G-R G/R G-V G/V ± ± ± ±
Colour Yellow Yellow-Black Yellow-Red Yellow-Green ± ±
Code H H-G H/G H-N H/N H-R H/R ± ± ± ±
Colour Grey Grey-Yellow Grey-Black Grey-Red ± ±
Code L L-G L/G L-N L/N L-R L/R ± ± ± ±
Colour Blue Blue-Yellow Blue-Black Blue-Red ± ±
Code M M-B M/B M-N M/N ± ± ± ± ± ±
Colour Brown Brown-White Brown-Black ± ± ±
Code N ± ± ± ± ± ± ± ± ± ±
Colour Black ± ± ± ± ±
Code R R-N R/N R-V R/V ± ± ± ± ± ±
Colour Red Red-Black Red-Green ± ± ±
Code S S-G S/G S-N S/N ± ± ± ± ± ±
Colour Pink Pink-Yellow Pink-Black ± ± ±
Code V V-B V/B V-N V/N V-R V/R ± ± ± ±
Colour Green Green-White Green-Black Green-Red ± ±
Code Z Z-B Z/B Z-G Z/G Z-N Z/N ± ± ± ±
Colour Violet Violet-White Violet-Yellow Violet-Black ± ±
COMPOSITION OF THE COLOURS
The coloration of two-colour wires is indicated by the composition of the symbols listed.
Example: G-V = Yellow-Green with longitudinal colouring.
G/V = Yellow-Green with transversal colouring.
ELECTRIC
16. WEIGHT TABLE
00-12 WB70A-1
This weight table is a guide for use when transporting or handling components.
Unit: kg
Machine model WB70A-1
From serial no. F10392-
Engine assembly 250
Radiator - exchanger ±
Hydraulic tank (without hydraulic oil) 62
Fuel tank (without fuel) 45
Rear frame 535
Front frame 450
Joint 75
Counterweight 1400
Loader arm 255
Loader bucket 360
Tie-rod 32
Tilt lever 42
Cab ±
Seat ±
Engine hood ±
Piston pump 33
Hydraulic motor 28
Transmission ±
3-spool control valve 20
Control valve support 8
Front axle ±
Rear axle ±
Wheel, assy. ±
Backhoe
Backhoe, assy. (without bucket) ±
Boom 160
Arm 110
Jig arm 211
Swing bracket 72
Backframe 106
Backhoe frame 241
Side digging boom ±
6-spool control valve 34
7-spool control valve 38
Control valve support 22
Boom cylinder ±
Arm cylinder ±
Bucket cylinder ±
Swing cylinder ±
Outrigger cylinder ±
Work equipment ±
17. NOTE:
(1) When fuel sulphur content is less than 0.5%,
change oil in the oil pan ebery periodic mainte-
nance hours described in operation and mainte-
nance manual. Change oil according to the follow-
ing table if fuel sulphur content is above 0.5%.
Fuel sulphur content Engine oil change interval
0.5 to 1.0% 1/2 of regular interval
Above 1,0% 1/4 of regular interval
(2) When starting the engine is weathers temperature be-
low 0ëC, be sure to use engine oil SAE 10W, SAE
20W-20, even if weather temperature goes up to
10ëC day time.
(3) Use classification CD as engine oil, if use classifi-
cation CC, reduce the engine oil change interval to
half.
(4) Use original products, which have characteristics
specifically formulated and approved for the engine,
the hydraulic circuit of equipment and for reductions.
TABLE OF OIL AND COOLANT QUANTITIES
00-13WB70A-1
RESERVOIR
KIND OF
FLUID
AMBIENT TEMPERATURE CAPACITY ( <)
±20 ±10 0 10 20 30ëC Specified Refill
Crankcase sump
OIL
. API CD-SG
. MIL-L-2104 E
. CCMC D2-G2
10 10
Hydrostatic
transmission and
hydraulic circuit
OIL
. ATF DEXRON
Only loader:
100
65With
backhoe:
133
Braking system
OIL
. ATF DEXRON
0.5 0.5
Front axle
. differential
OIL
. UTTO FLUID
4 4
. final red. gear (each) 0.9 0.9
. Reduction gear 1.7 1.7
Rear axle:
. differential
5.2 5.2
. final red. gear (each) 0.9 0.9
Fuel tank DIESEL OIL 70 ±
Engine coolant
system
WATER+
ANTI-FREEZE
15 ±
WATER 15 ±
PERMANENT
LIQUID
15 ±
] ASTM D975 N. 1
ASTM: America Society of Testing and Materials
SAE: Society of Automotive Engineers
API: American Petroleum Institute
MIL: USA Military Specification
CCMC: Common Market Constructors Committe
Specified capacity: Total amount of oil including oil for components and oil in piping.
Refill capacity: Amount of oil needed to refill system during normal inspection and maintenance.
]
SAE 10W
SAE 20W-20
SAE 30
SAE 40
SAE 15W/30
ASTM D975 N. 2
23. REDUCTION RATIO
Reduction gear
(Transmission)
Differential Planetary Total axle Total
High speed 1.093
3.22 5.25 16.915
18.47
Low speed 4.06 68.6
1. Engine (Diesel)
2. Hydraulic pump
3. Travel motor
4. Transmission
5. Drive shaft
6. Front axle
7. Rear axle
8. Front wheels
9. Rear wheels
POWER TRAIN
10-3WB70A-1
D0400766
4
Fronte macchina
Z=51
6 Z=29 Z=9
Z=73
Z=47Z=43
Z=18
8
Z=19
Z=12
Z=51
Z=29 Z=9
7
53
2
1
Z=12
Z=19
9
Front of machine
24. a. A Port - From ST1 solenoid valve group
(A3 Port)
b. B Port - From ST1 solenoid valve group
(A4 Port)
1. Flange
2. Filler and level oil plug
3. Oil drain plug
4. Neutral manual control
5. Low speed selector piston
6. High speed selector piston
7. Selector gear
8. Selecting fork
9. Speed sensor
10. Safety switch
11. Selector shaft
12. Spring
13. Ball
14. Piston
TRANSMISSION
10-4 WB70A-1
D0400749
11
10
9
8
76
5
B
B
12 13
14
4
1
3
2
a b
A
A
Sezione B - BSection B - B
29. DIFFERENTIAL LOCKING
(H Only for rear axle)
a. B Port - From ST1 solenoid valve group
(A1 Port)
1. Nut
2. Cylinder
3. Spring
4. Piston
5. Ring nut
6. Bleeding screw
7. Sleeve
8. Fork
10-9WB70A-1
D0400757
41 32
A
5
A
78
6
a
Sezione A - ASection A - A
30. a. From brake pump
1. Brake bleeding screw
2. Adjusting screw
3. Nut
4. Push-rod
5. Disk release spring
6. Adjusting screw
7. Brake disk
8. Brake lever
9. Pressure disk
10. Pressure lever
11. Brake piston
PARKING AND WORKING BRAKE
(H Only for rear axle)
10-10 WB70A-1
D0400758
9
4 65
7
10
1 32
11 710
8a
32. TRANSMISSION COMPONENTS
Machine travel is obtained via a closed circuit hydro-
static transmission including:
1- Reversible and variable displacement axial piston
hydraulic pump direct-coupled on diesel engine.
2 - Variable displacement axial piston hydraulic mo-
tor direct-coupled on transmission.
They are connected by hoses (A - B).
On «closed circuit» system have been installed also
following devices:
On hydraulic pump
a - Electrodistributor (5) to select hydraulic motor ro-
tation direction.
b - Pressure cut-off valve (6).
c - By-pass valve (7).
d - Control valve (8).
e - Inching valve (9).
f - Main relief valve (4).
On hydraulic motor
g - Automatic displacement control device according
to working pressure (10).
h - Additional piloting (11).
i - Recognition device for travel direction (12).
l - Oil exchange valve (13).
HYDROSTATIC TRANSMISSION
10-12 WB70A-1
D0400783
A
B
Pompa idraulica
Motore idraulico
6
5
7
7 4 8
9
10
11
12
13
1
2
14
3
Hydraulic pump
Hydraulic motor
33. . Pump shaft (1), (which drags cylinder barrel) is ro-
tates by the engine.
. Moving the positioning piston (2) the swash plate is
shifted from neutral position; an angle is fixed be-
tween pistons and swash plate (on which pistons
are constrained); this angle will create a volume dif-
ference in one side smaller and in the other side
bigger. In this way it is created an oil pressure de-
livery area (hydraulic power) through hydraulic mo-
tor (pipe A on diagram) and a suction area from hy-
draulic motor (pipe B on diagram).
. The oil sent from pump to motor (pipe A), pressing
on pistons, will move pistons and consequently the
output shaft (14), transforming «hydraulic power»
into «mechanical power».
. The oil transferring power is returned through pipe
(B) to hydraulic pump's suction port to be reused.
. This is the «closed circuit» principle which, theoreti-
cally, utilises once again the same oil quantity.
NOTE - Moving the positioning piston in the other di-
rection, it will create the reversal direction of engine
rotation.
. Oil leakages between moving parts, cause, during
machine's life, the emptying of closed circuit; this
trouble is solved applying a gear pump (3) named
boosting pump, which sucks oil from the hydraulic
tank and introducing it into the closed circuit keep-
ing inside constant pressure, checked by a fixed
setting main relief valve (4).
. Part of pressurised oil of the boosting circuit is used
for positioning piston (2) operation which allows the
stepless variable inclination of the swash plate and
therefore the hydraulic motor speed.
. All the system is protected from pressure peaks
(and therefore from overloads) by safety valves (7).
HYDROSTATIC TRANSMISSION OPERATION
10-13WB70A-1
D0400773
A
4
6
5
7 8
9
10
11
12
13
14
1
3
2
Blocco
cilindri
Piatto
oscillante
B
7
POMPA MOTORE
PUMP MOTOR
Swash
plate
Cylinder
barrel
34. a. B Port - To travel motor (A Port)
b. A Port - To travel motor (B Port)
c. S Port - From hydraulic oil tank
d. T2 Port - To hydraulic oil tank
e. T1 Port - To travel motor (T1 Port)
f. PS Port - To INCH device (A Port)
g. G Port - To ST1 solenoid valve group
(P Port)
1. EV6 REVERSE gear selection
2. Initial adjusting valve
3. Main relief valve
4. EV7 FORWARD gear selection
5. Cut pressure valve
6. Boosting valve
7. Positioning cylinder
SPECIFICATIONS
Max displacement: 40 cc/rpm
Max absorbance at 2000 rpm: 54 kW (80 ,/min)
Max pressure: 450 bar Max.
Max flow rate: 160 ,/min Max.
HYDROSTATIC TRANSMISSION PUMP
10-14 WB70A-1
a
a
g
e
f
c
5
3
6
A
b
3
d
1
4
7
2
A
D0400694
35. 1. Feed pump gear
2. Feed pump body
3. Rotating cylinder
4. Central spring
5. Piston
6. Swash plate
7. Motor shaft
8. Spring
9. Valve plate
10. Feed pump shaft
11. Positioning cylinder external spring
12. Positioning cylinder internal spring
13. Nut
14. Piston centering adjusting screw
15. Positioning cylinder cover
16. Positioning piston
10-15WB70A-1
D0400701
B
4 65
7
8
9
10
11
12
13
14
15
1
3
2
A
16
Sezione B - B
Particolare A
B
Sezione A - ASection A - A
Section B - B
Detail A
36. 1 - BOOSTING CIRCUIT
Description
The boosting circuit apart to complete the oil scattered
by leakages of the closed circuit, supplies the piloting
pressure needed to move the positioning piston (2)
which checks the oil flow pressure variations through
the motor.
The constant pressure is obtained by means a fixed
setting main relief valve (4).
Operation
. When the engine is started, through the main shaft
(1) of variable axial piston pump, it rotates the gear
pump (3).
. Flow rate of gear pump gets through initial adjust-
ing valve (8) and then across the check valves (7)
pressurises the complete hydrostatic circuit until
the pressure value checked by the main boosting
relief valve (4).
. Exceeding flow rate is sent directly to exhaust.
10-16 WB70A-1
D0400774
4
7
8
1
2
1
7
Ramo B
Ramo A
Al motore
3
Pipe B
Pipe A
To motor
D0400714Spessore di taratura
Al ramo B
Valvola di max pressione (4)
dalla pompa (3)
Scarico
Main relief valve (4)
From pump (3)
Exhaust
To pipe B
Setting shim
37. Function
. The function of this valve is to supply to positioning
piston a piloting proportional pressure to engine re-
volutions.
1 - External fixed part
2 - Internal sliding part
3 - Contrast spring
4 - Gauged diaphragm
5 - Adjusting screw
6 - Gear pump
7 - Solenoid valve
8 - Positioning piston
Operation
1 - Flow rate of gear pump (6), acrossing lengthwise
the valve leaves out through exhaust port a. The
crossover of diaphragm (4) by the flow rate, gen-
erates (Dp)a pressure drop created by the pump
(6). The pressure P1 exhisting before diaphragm
(4) (which is upper to the internal pressure P2 into
the valve), acts on surface of the sliding part (2)
opposed by spring (3).
P1 - Pressure before the diaphragm
P2 - Pressure after diaphragm
P3 - Piloting pressure
2 - INITIAL ADJUSTING VALVE AND DISPLACEMENT CHANGE ACCORDING TO ENGINE SPEED
10-17WB70A-1
A
B7
8
P1 P2
D0400712
a
5
1
3
2
4
b
6
D0400849
P
P2
∆ p
∆ p = f (Q)
Q = f (n)
P3
P1
38. 1 - External fixed part
2 - Internal sliding part
3 - Contrast spring
4 - Gauged diaphragm
5 - Adjusting screw
6 - Gear pump
7 - Solenoid valve
8 - Positioning piston
The movement of the sliding part (2) on fixed part
(1), opens the port b allowing an oil flow having a
checked pressure (and therefore fixed), to reach
the solenoid valve (7) and later the positioning pis-
ton (8).
The principle that the pressure acting on position-
ing cylinder is proportional to the Diesel engine re-
volutions, derives from the following considera-
tions:
a - The quantity of pressurised oil which reaches
the solenoid valve (7) depends from the flow
section between the fixed part (1) and the slid-
ing part (2) of the valve.
b - The flow section depends from the force gen-
erated on sliding part (2) surface, by the pres-
sure difference generated by the oil volume
acrossing the diaphragm (4). (Dp=f(Q))
c - The oil volume sent from gear pump (6) to initi-
al regulation valve is directly proportional to
the Diesel engine revolutions. (Q=f(n))
2 - If the Diesel engine revolutions is low, the pump
delivery is also low and the force generated by
the pressure difference on sliding part (2), is not
sufficient to compress the spring (3) and therefore
any gallery will be opened between the fixed part
(1) and the sliding part (2). Acting on adjusting
screw (5), it is possible to fix the idle engine to per-
mit the hydraulic pump regulation and, conse-
quently the motion of the machine.
3 - If during the work the Diesel engine idle speed de-
creases, this causes the following decrease:
. hydraulic pump delivery;
. pressure difference between the two sides of
diaphragm (4);
. the force acting on sliding part (2);
. pressure P3 acting on positioning piston (8)
which, pushed by the springs, returns towards
the centre of cylinder.
Therefore it is obtained a displacement decrease
which will stop only when the balance is resetted
between torque supplied by Diesel engine and
the torque absorbed by the hydrostatic transmis-
sion.
10-18 WB70A-1
A
B7
8
P1 P2
D0400712
a
5
1
3
2
4
b
6
39. 3 - POSITIONING CYLINDER
Function
. Positioning cylinder (1) is the actuator that moves
the swash plate to address the pump's oil flow into
pipe A or B and therefore to fix the travel direction
of machine.
. The oil flow direction is fixed by the excitation of the
magnets (2) ± (3) of solenoid valve (4) by means of
selector of machine's travel direction.
Operation
. The selector of machine's travel direction, ener-
gises a magnet (in the example the magnet (3)
which movable core moves the distribution piston
(5), allowing the oil passage coming from initial ad-
justing valve (6) towards the positioning cylinder
(1).
. When the idle speed of Diesel engine increases,
the pressure coming from the oil gallery a by
means of initial adjusting valve (6), increases in
proportional manner and acting on surface b of pis-
ton (7) causing a movement bared by the centering
springs (8).
. The movement of piston (7) causes a movement of
swash plate (9) of pump which, increasing the an-
gle, moves the pistons (10) inside the cylinder bar-
rel (11), creating the suction and the delivery zones.
10-19WB70A-1
A
B
1
b
D0400775
7
9 10 11
4
3
2
7
8
5
a
a
6
40. 4 - PRESSURE CUT VALVE
Function
. The valve limits the maximum relief pressure of hy-
drostatic transmission before the intervention of
safety valves, cutting the piloting pressure and can-
celling partially the pump oil flow. The valve, acting
on piloting circuit, permits to limit the maximum
pressure supplied by the initial adjusting regulation
valve (1) limiting the direct flow to positioning pis-
ton, avoiding the intervention of safety valves and
therefore without any oil leakage and oil overheat-
ing.
Operation
. The valve includes a slider (2) which intercepts the
piloting pressure coming from initial adjusting valve
(1) and going to positioning cylinder (3). The slider
(2) is moved by the higher pressure of closed circuit
in contrast with the adjusting spring (4). The pres-
sure exhisting in the pressure line of closed circuit
(line A on the drawing) selects the oil passage
through flow selection valve (5) and, pressing on
plunger (6) and therefore on slider (2), engages
the spring (4). When the setting value is reached,
the slider (2) lifts itself putting in communication
the chamber a of piloting pressure, with relief
chamber b; the effect of piloting pressure drops,
causing a positioning piston backing and therefore
a swash plate repositioning, until a balance condi-
tion is reached to allow the minimum flow rate hold-
ing, necessary to setting pressure value (stand-by
condition).
. The pressure cut valve must be adjusted to operate
at a lower pressure compared with the safety
valves setting; the adjustment is obtained with the
screw (7) which acts directly on contrast spring (4).
10-20 WB70A-1
A
B
D0400715
6
5
7
2
4
a
b
a
b
1
3
41. 5 - SAFETY VALVES
The safety valves are used to protect the hydro-
static circuit from pressure peaks which exceed
the maximum permissible value for hydraulic
pump.
The valves are dual cartridge movable type, separat-
ing the low pressure line from the other high pressure
line and both are fitted on delivery line.
When the restrictor (1) is opened, exceeding pressure
is sent directly from high pressure line into low pres-
sure line.
The safety valves must operate only in special case
and only for a short time period because the oil leak-
age following the opening of the valve (1), produces
heat and therefore the oil overheating inside the
closed circuit.
The safety valves setting must be done on test bench
and is obtained adjusting the restrictor (1) into the seat
(2) of the contrast spring (3).
The position is fixed by the screw (4).
10-21WB70A-1
D0400713
Alta
pressione
4
1
2
3
Bassa pressioneLow pressure
High
pressure
42. a. A Port - From hydrostatic transmission
pump (PS Port)
b. B Port - To ST1 solenoid valve (T Port)
1. Valve body
2. Control lever
3. Spool
4. O-Ring
5. O-Ring
INCH VALVE
The function of this valve is to send to relief all or part
of piloting flow acting on positioning piston, to limit the
displacement and therefore the machine speed inde-
pendently from Diesel engine revolutions.
The engine power not utilised for the swing function
remains at disposal for the work equipments.
INCHING VALVE
10-22 WB70A-1
D0400767
A
a
b
A
Sezione A - A
4
5
1
3
2
Section A - A
43. a. A Port - From hydrostatic transmission
pump (B Port)
b. T1 Port - From hydrostatic transmission
pump (T1 Port)
c. B Port - From hydrostatic transmission
pump (A Port)
d. T Port - To oil radiator (C1 Port)
1. EV8 Additional piloting device
2. Automatic variable displacement device
3. EV9 Detection of travel direction device
4. Oil exchange valve
TRAVEL MOTOR
10-23WB70A-1
D0400695
1
4
2
a
d
3
c
bX
Vista XView X
44. 1. Output shaft
2. Front bearing
3. Rear bearing
4. Cylinder block
5. Pistons
6. Swash plate
7. Minimum displacement lock
8. Maximum displacement lock
9. Positioning piston
10. Measuring piston spring
11. Adjustment piston
12. Automatic start adjusting regulator
13. One way valves
14. Orifice
15. Flow selector
16. Centering spring
17. Spool
18. Check valve
19. Orifice
10-24 WB70A-1
D0400776Sezione B - B
A
A
Sezione A - A
B
B
6
10
12
4 57
8
9
11
13
14
1516
13 2
13
17
16
19
18
Section A - A
Section B - B
45. 1 - AUTOMATIC VARIABLE DISPLACEMENT DEVICE
Function
. This device is used to change automatically the dis-
placement according to operation pressure. The in-
crease of displacement involves a reduction of
crankshaft revolutions and an increase of output
torque.
Operation
. Oil coming from pump, after crossover the check
valves a and the recognition of travel direction
valve (12), reaches the piston b, and the smaller
surface of positioning piston c pushing it towards
the minimum flow rate displacement through an ad-
justing screw d.
. When the pressure inside the circuit increases, the
adjustment piston b, acting in contrast with spring e
moves, allowing to oil to go through the gallery k
into the chamber f and to act on bigger surface of
positioning piston c.
. The forces difference acting on positioning piston c
allow the movement of cylinder block g on which it
is mechanically blocked until a balance condition is
reached between forces acting on both surfaces of
positioning piston c or, until to reach the maximum
displacement. The maximum displacement is ob-
tained by mechanical lock h.
. When into the delivery gallery the pressure de-
creases, the balance of forces acting on positioning
piston c, is cutted; the measuring piston b, moves
opening the gallery m which puts in relief the pres-
sure exhisting into the chamber f.
. The positioning piston c gradually returns towards
the minimum displacement position; the movement
is stopped when a new balance is reached between
the forces acting on positioning piston c.
10-25WB70A-1
D0400777
12
e
k
m
c
b
h
g
f d
aa
46. 2 - ADDITIONAL PILOTING
Function
. This device allows to cut the automatic variable dis-
placement and to take the engine to maximum dis-
placement.
Operation
. When the magnet B is energised, the actuator (9)
pushes on adjusting piston (5) which switches al-
lowing the oil passage through the gallery k, into
the chamber f of the bigger surface of positioning
piston (2).
. The pressure difference moves the positioning pis-
ton (2) which is mechanically connected to cylinder
barrel of motor; the piston moves the cylinder barrel
increasing the displacement.
The movement of positioning piston (2) continues
up to maximum displacement, fixed by the me-
chanical block (7).
. When the magnet is no more energised the adjust-
ing piston (5) moves opening the gallery m which
sends in relief the pressure exhisting into the cham-
ber f. The positioning piston (2) gradually returns
towards the minimum displacement position; the
movement is stopped when a new balance is
reached between the forces acting on adjusting pis-
ton (5) and on positioning piston (2). From this mo-
ment the change of displacement becomes auto-
matic.
10-26 WB70A-1
D0400778
f
k
m
5
7
9
2
B
47. 3 - RECOGNITION OF TRAVEL DIRECTION DEVICE
Function
. This device secures that the pressure acting on ad-
justing piston (5) is the one coming from the high
pressure gallery corresponding to travel direction
of machine; preselected by the selector putted
near the steering wheel. This avoids that the inver-
sion of pressures between the circuit branches
caused by the negative loads (as example during
the sloping travel) cause sudden and not wanted
displacement changes.
Operation
. The magnet (1) device, acts on spool (2) which in-
tercepts the pressure coming from branches A
and B of closed circuit through the check valve a.
. When the magnet (1) is in rest position, the spool is
held in position by the spring (3). The spool allows
the passage of pressure of branch A and prevents
the passage of pressure of branch B.
. When the magnet (1) is energised, the spool closes
the passage of pressure coming from branch A and
allows the passage of pressure of branch B.
4 - OIL EXCHANGE VALVE
Function
. The valve takes the oil from low pressure branch of
closed circuit to send it inside the motor housing to
join the oil leakage sent to relief. The oil quantity
leaving from the circuit is restored by means of
boosting circuit which supplies oil strained and hav-
ing a lower temperature.
Operation
. When machine is stopped, with pump in neutral po-
sition, the hydraulic motor is stopped and both
branches of transmission are feed by boosting
pressure. The same pressure acts also on both flow
regulator (1) sides which remains in neutral posi-
tion. When Diesel engine is stopped the regulator
is held in neutral position by springs (2) and (3).
. When into branch transmission (A) the operation
pressure increases, the flow selector (1) moves
and the opposite branch transmission oil (B), pas-
sing through the diaphragm (4), is putted into the
motor housing after the opening of valve (5).
. The same operation principle is valid also for the
opposite branch.
10-27WB70A-1
D0400779
3
2
1
5
B A
A
B
D0400780
12 4 53
A B
48. DESCRIPTION
. Steering is completely hydraulic.
The necessary oil, supplied by the pump (1) oper-
ated by the engine (2), is sent by the «Load Sen-
sing» priority valve (3).
The priority valve must sent the necessary oil quan-
tity to the steering unit (4) even when the other hy-
draulic components are serviced by the same cir-
cuit. From the steering unit, operated by the steer-
ing wheel (5), oil is sent into the steering cylinders
(6) connected to front frame (7) and to joint (8).
STEERING SYSTEM
10-28 WB70A-1
RKZ03850
4
6
5
7
8
1
3
2
6
49. a. P Port - To priority valve (P Port)
b. S Port - From hydraulic tank
1. Drive gear
2. Snap ring
3. Oil seal
4. Bushing
5. Side plate
6. Driven gear
7. Pump body
8. Front flange
SPECIFICATIONS:
Theoretical displacement:14.4 cc/rev
Delivery at 2000 rpm: 28.8 ,/min
Rated pressure: 260 bar
Max. pressure: 320 bar
STEERING SYSTEM PUMP
10-29WB70A-1
D0400698
a
4
6
5
7
8
1
3
2
b
50. a. L Port - To R.H. steering cylinder (Bottom
side)
b. R Port - To L.H. steering cylinder (Bottom
side)
c. T Port - To hydraulic tank
d. P Port - From priority valve (CF Port)
e. LS Port - From priority valve (LS Port)
SPECIFICATIONS
Steering unit type: OSPC200LS
Rated discharge: 20 ,/min
OPERATION
. The steering unit consists of a control valve and a
rotating oil dispenser and functions hydrostatically.
. When the steering wheel is moved, the control
valve sends oil from pump P2 (through the rotating
oil dispenser) to one or other of the chambers of the
steering cylinder. The rotating oil dispenser en-
sures that the amount of oil supplied to the cylinder
is proportional to the rotation angle of the steering
wheel.
. In the steering unit pump malfunctions the oil dis-
penser functions automatically like a hand-pump
to ensure emergency steering.
STEERING UNIT
10-30 WB70A-1
D0400020
b
dc
ea
51. a. P Port - From pump P2 (P Port)
b. LS Port - To steering unit (LS Port)
c. CF Port - To steering unit (P Port)
d. EF Port - To 3 spool control-valve
(T2 Port)
SPECIFICATIONS
Type: OLS 40
OPERATION
. The oil from pump is distributed through the priority
valve to the steering unit (CF Port) and to the other
hydraulic components (EF Port).
. Distribution is determined by the position of the
priority valve slider in function of:
a - the Load Sensing signal coming from the steer-
ing unit (LS Port);
b - the pump oil delivery;
c - the pressure in the steering system;
d - the pressure in the connected hydraulic circuit.
. The slider position is such as to ensure that deliv-
ery to the steering unit always corresponds to the
actual requirements.
PRIORITY VALVE
10-31WB70A-1
D0400036
a
b
cd
52. 1. Joint
2. Spacer
3. Bushing
4. Joint flange
5. Bushing
6. Fitting
7. Spacer
8. Spacer
FRAMES KNUCKLE AND JOINT
10-32 WB70A-1
RKZ03860
A
4
1 2 3
55
2
6
4
8
5
7
5
CParticolare A
Particolare C
Particolare B
B
3
2
Detail A
Detail B
Detail C
53. HYDRAULIC CIRCUIT DIAGRAM
10-33WB70A-1
65 ഞ
3 bar
A2
B2
B6
G
LS
T2
A2A1A3 B2A4
A6
A5
B5
A4
B4
A3
B3
T
P
T1
A
C
B
EV7
X1X2GMHSFSA
RT1
TU
LS T P
L R
P
CF EF
B1 A1
T1
T2P
T
P1
P
T
B
R.H. equipment port
Lift cylinder
200kg/cm2
Dump cylinder
Curl
Dump
3-spool control valve
Knuckle locking
cylinder
Priority
valve
A
A
EV3
EV8
Travel motor A6VM55
M1 T1B
EV6
P2 Pump:
theorical displacement
14.2 cc/rev
Rearaxle
B
Differential
locking
6-spool control valve
(parallel type)
Backframe locking cylinder
sx
sxdx
dx
L.H. outrigger
cylinder
Dump
Curl
In
Out
Backframe
locking cock
Hydraulic
tank
Suction filter 60
Hydrostatic transmission strainer 10
Engine 4D98E-1FA:
51.1 kW at 2500 rpm
Hydrostatic transmission
P1 pump A4VG40
P3 Pump:
theorical displacement
26.5 cc/rev
Inching valve
Boom cylinder
Arm cylinder
MA
MB
B Fa PS
Lower
Raise
Lower
Raise
B2 A2 B3 A3
210 kg/cm2
170kg/cm2
195kg/cm2
270kg/cm2 270 kg/cm2
190 kg/cm2
160 kg/cm2
160 kg/cm2
170kg/cm2
210 kg/cm2
210 kg/cm2
230 kg/cm2
160 kg/cm2
160 kg/cm2
EV1 EV2 EV3 EV4
Steering unit
Frontaxle
R.H. boom swing
cylinder
L.H. boom swing
cylinder
A1
B1
3 bar
65 ഞ
L.H. steering cylinder
S
P
S
Right
Left
D0401092
Lift cylinder
L.H. equipment port
Lower
Raise
R.H. steering cylinder
Bucket cylinder
R.H. outrigger
cylinder
Lower
Raise
Lower
Raise
P
54. 10-34 WB70A-1
B7
A7
B1
A1
B2
A2
B3
A3
B4
A4
B5
A5
A6
T1
PT
210 kg/cm2
210 kg/cm2
210 kg/cm2
190 kg/cm2
190 kg/cm2
270 kg/cm2
190 kg/cm2
B6
A7
B1
A1
B2
A2
B3
A3
B4
A4
B5
A
B6
A6
B7
T1
PT
210 kg/cm2
190 kg/cm2
190 kg/cm2
270 kg/cm2
210 kg/cm2
190 kg/cm2
210 kg/cm2
B7
A7
B1
A1
B2
A2
B3
A3
B4
A4
B5
A5
B6
A6
T1
PT
210 kg/cm2
190 kg/cm2
190 kg/cm2
270 kg/cm2
210 kg/cm2
210 kg/cm2
190 kg/cm2
RKZ03961
160 kg/cm2
210 kg/cm2
270 kg/cm2
270 kg/cm2
Lower
Raise
Left
Right
Dump
Curl
Lower
Raise
7-SPOOL CONTROL VALVE
FOR HAMMER
7-SPOOL CONTROL VALVE
FOR SIDE DIGGING BOOM
7-SPOOL CONTROL VALVE
FOR JIG ARM
Jig arm cylinder
Lower
Raise
Right
Dump
Curl
Lower
Raise
Left
Out
Boom cylinder
L.H. boom swing cylinder
Bucket cylinder
Arm cylinder
L.H. outrigger cylinder
R.H. outrigger cylinder
R.H. boom swing cylinder
Side digging
boom cylinder
Lower
Raise
Left
Right
Lower
Raise
Lower
Raise
Dump
Curl
Right
Left
Boom cylinder
L.H. boom swing cylinder
Bucket cylinder
Arm cylinder
L.H. outrigger cylinder
R.H. outrigger cylinder
R.H. boom swing cylinder
Hammer
Lower
Raise
Boom cylinder
L.H. boom swing cylinder
Bucket cylinder
Arm cylinder
L.H. outrigger cylinder
R.H. outrigger cylinder
R.H. boom swing cylinder
Lower
Raise
Out
In
In In In
OutOut
55. a. T2 Port - From priority valve (EF Port) and
from backhoe control valve (P Port)
b. P Port - From pump P3 (P Port)
c. B3 Port - To lift cylinder (Bottom side)
d. B2 Port - To dump cylinder (Bottom side)
e. A1 Port - To auxiliary attachments (R.H. side)
f. B1 Port - To auxiliary attachments (L.H. side)
g. A2 Port - To dump cylinder (Head side)
h. A3 Port - To lift cylinder (Head side)
i. T1 Port - To hydraulic oil tank
1. Main relief valve
2. Safety-suction valve
3. Spool (Optional attachments)
4. Spool return spring
5. Check valve
6. Spool (Bucket)
7. Spool (Lift arm)
8. Safety valve
3-SPOOL CONTROL VALVE
10-35WB70A-1
RKZ03361
Sezione A - A
a
4
32
4
5 55
67 8
2 8
i
Sezione B - B Sezione C - C
4
1
C
C
B
B
A
A
f
gh
c
d e
b
Section A - A Section B - B Section C - C
56. a. T1 Port - To backframe locking cock (A Port)
b. A6 Port - To boom cylinder (Bottom side)
c. A2 Port - To bucket cylinder (Bottom side)
d. A3 Port - To R.H. outrigger safety valve
(V1 Port)
e. A4 Port - To L.H. outrigger safety valve
(V1 Port)
f. A5 Port - To R.H. boom swing cylinder
(Head side)
g. A1 Port - To arm cylinder (Head side)
h. Port T - To shovel control valve (T1 Port)
i. P Port - To backframe locking cock (C Port)
l. B1 Port - To arm cylinder (Bottom side)
m. B5 Port - To L.H. boom swing cylinder
(Head side)
n. B4 Port - To L.H. outrigger safety valve
(V2 Port)
o. B3 Port - To R.H. outrigger safety valve
(V2 Port)
p. B2 Port - To bucket cylinder (Head side)
q. B6 Port - To boom cylinder (Head side)
r. P Port - To 3-spool control valve (T2 Port)
6-SPOOL CONTROL VALVE
10-36 WB70A-1
RKZ03810
ha ir
A
A
b
q
B
B
c
p
C
C
d
o
C
C
e
n
D
D
f
m
E
E
g
l
57. 1. Spool (Boom)
2. Safety-suction valve
3. Check valve
4. Safety valve
5. Spool return spring
6. Spool (Bucket)
7. Suction valve
8. Spool (Outrigger)
9. Spool (Boom swing)
10. Spool (Arm)
10-37WB70A-1
RKZ03820
3
1 2
5 4
3
6 2
5 7
3
8
5
3
9 4
5 4
3
10 7
5 2
Sezione A - A Sezione B - B Sezione C - C
Sezione D - D Sezione E - E
Section A - A Section B - B Section C - C
Section D - D Section E - E
58. a. A7 Port - To side digging boom cylinder
(Bottom side)
b. B7 Port - To side digging boom cylinder
(Head side)
c. A7 Port - To jig arm cylinder (Bottom side)
d. B7 Port - To jig arm cylinder (Head side)
e. B7 Port - To hydraulic breaker
7-SPOOL CONTROL VALVE
10-38 WB70A-1
RKZ0
Per deportabile
Per telescopico
Per martello
A
A
a
b
B
B
c
d
e
C
C
D
D
For side digging boom
For jig arm
For hammer
59. 1. Spool (Side digging boom)
2. Safety-suction valve
3. Check valve
4. Spool return spring
5. Spool (Jig arm)
6. Spool (Hydraulic breaker)
7. Plug
8. Safety valve
9. Spool (Bucket)
10-39WB70A-1
RKZ03840
3
1 2
4 2
Sezione A - A
3
5
4
Sezione B - B
3
6 7
4 8
Sezione C - C
3
9 2
4 2
Sezione D - D
Section A - A Section B - B
Section C - C Section D - D
60. MAIN RELIEF VALVE
1. Safety valve
2. Spring
SETTINGS
3-spool control valve: 200 bar
6-spool control valve: 190 bar
7-spool control valve: 190 bar
VALVES
10-40 WB70A-1
RKZ03660
1
2
RKZ03370
1
2 3 4
SAFETY-SUCTION VALVE 1. Suction valve
2. Safety valve
3. Spring
4. Spring
SETTINGS
. 3-Spool control valve:
- Bucket cylinder bottom side: 270 bar
- Bucket cylinder head side: 195 bar
. 6-Spool control valve:
- Boom cylinder bottom side: 210 bar
- Arm cylinder bottom side: 210 bar
- Bucket cylinder bottom side: 210 bar
. 7-Spool control valve for side digging boom:
- Side digging boom cylinder bottom side: 270 bar
- Side digging boom cylinder head side: 270 bar
. 7-Spool control valve for hammer:
- Bucket cylinder bottom side: 210 bar
- Bucket cylinder head side: 210 bar
RKZ03380
1 2
SAFETY VALVE
1. Safety valve
2. Spring
SETTINGS
. 3-Spool control valve:
- Auxiliary attachments L.H. side: 170 bar
- Auxiliary attachments R.H. side: 170 bar
. 6-Spool control valve:
- Boom cylinder head side: 270 bar
- R.H. boom swing cylinder head side: 190 bar
- L.H. boom swing cylinder bottom side: 190 bar
. 7-Spool control valve for hammer:
- Hammer delivery: 160 bar
61. SUCTION VALVE
1. Valve
2. Spring
. 6-Spool control valve:
- Bucket cylinder head side
- Arm cylinder head side
10-41WB70A-1
RKZ03970
12
RKZ03390
3
2
1
CHECK VALVE
1. Check valve
2. Spring
3. Body valve
62. a. S Port - From hydraulic tank
b. P Port - To 3-Spool control valve (P Port)
1. Input shaft
2. Pump body
3. Cover
SPECIFICATIONS:
Theoretical displacement:
26.5 cc/rev
Delivery at 2000 rpm: 53 ,/min
Rated pressure: 210 bar
Max. pressure: 250 bar
GEAR PUMP
10-42 WB70A-1
D0400704
a
1
32
b
x
z
Vista Z Vista X
View Z View X
63. a. V1 Port - R.H. outrigger:
from 6-spool control valve (A3 Port)
L.H. outrigger:
from 6-spool control valve (A4 Port)
b. V2 Port - R.H. outrigger:
from 6-spool control valve (B3 Port)
L.H. outrigger:
from 6-spool control valve (B4 Port)
c. C2 Port - To outrigger cylinder (Bottom side)
d. C1 Port - To outrigger cylinder (Head side)
OUTRIGGER SAFETY VALVES
10-43WB70A-1
D0400060
a b
c d
D0400061
16
14
12
10
8
6
4
2
0
0 6 12 18 24 30
Differenzadipressione⌬p(bar)
Portata Q (l/ min)
C2➔
V2V2➔C2
64. 1. Pump body
2. Main piston
3. Oil brake tank
4. Union
5. Oil seal
6. Piston
7. Detaching valve spring
8. Pump spring
9. Plug
10. Seal
11. Pin
12. Seal
13. Seal
14. Seal
15. Ball
16. Spring
17. Seal
SPECIFICATIONS:
Stroke: 36 mm
Displacement: 15 cc
Max. pressure: 150 bar
BRAKE PUMP
10-44 WB70A-1
4
65 7 8
91011121314151617
3
21
D0400699
66. LIFT CYLINDER
DUMP CYLINDER
STEERING CYLINDER
FRONT EQUIPMENT CYLINDER
10-46 WB70A-1
D0400685
4 65 7 8321
D0400687
4 65 7 8 9 10 11 12
13
321
D0400683
4 65 7 81 32
1. Head bushing
2. Piston rod
3. Cylinder head
4. Cylinder
5. Piston
6. Piston ring
7. Nut
8. Bottom bushing
1. Head bushing
2. Piston rod
3. Ring nut
4. Cylinder head
5. Oil seal
6. Guide ring
7. Cylinder
8. Thrust ring
9. Piston ring
10. Thrust ring
11. Dowel pin
12. Bottom bushing
13. Nut
1. Head bushing
2. Piston rod
3. Cylinder head
4. Cylinder
5. Piston
6. Piston ring
7. Piston nut
8. Bottom bushing
67. KNUCKLE LOCKING CYLINDER
SPECIFICATIONS
Cylinder Lift Dump Steering
Knuckle
locking
Piston rod size 40 50 25 18
Bore 70 95 50 30
Piston stroke 650 380 310 40
Max. stroke 1600 1400 910 Ð
Min. stroke 950 1020 600 Ð
Width across flats of piston nut 41 50 30 Ð
10-47WB70A-1
1. Piston rod
2. Snap ring
3. Oil seal
4. Cylinder head
5. Cylinder
D0400682
4 51 32
68. 1 - Bucket
2 - Bucket link
3 - Tilt lever
4 - Lift arm
5 - R.H. lift cylinder
6 - Bucket cylinder
7 - L.H. lift cylinder
FRONT WORK EQUIPMENT
10-48 WB70A-1
D0400769
4
6
1
5
3
2
7
69. CONTROL LEVER POSITION
Lift arm lowers
Lift arm raises
Bucket dump
Bucket curl
1 - Optional work equipment control lever
2 - Work equipment control lever
3 - Loader locking lever
1
2
3
4
LOADER CONTROL LEVER
10-49WB70A-1
D0400771
1
2
3
4
1
3
2
70. BOOM CYLINDER
ARM AND BUCKET CYLINDER
OUTRIGGER CYLINDER
BACKHOE CYLINDER
10-50 WB70A-1
D0400689
4 65 7 81 32
D0400684
4 65 71 32
D0400688
4 65 7 8 9
1011
1 32
1. Head bushing
2. Piston rod
3. Cylinder head
4. Cylinder
5. Piston
6. Piston ring
7. Guide ring
8. Screw
9. Bottom bushing
10. Bottom cushion plunger
11. Ball (No. 9)
1. Head bushing
2. Piston rod
3. Cylinder head
4. Cylinder
5. Piston
6. Piston ring
7. Guide ring
8. Bottom bushing
1. Piston rod
2. Cylinder head
3. Cylinder
4. Spacer
5. Guide ring
6. Piston ring
7. Piston
71. BOOM SWING
H The drawing shows R.H. boom swing cylinder
BACKFRAME LOCKING
10-51WB70A-1
1. Guide ring
2. Piston ring
3. Cylinder
4. Cylinder head
5. Swing bushing
6. Head bushing
7. Throttling
8. Spring
9. Spring guide
10. Circlip
11. Pin
12. Retaining ring
13. Piston
D0400680
Sezione A - A
4
6
5
8
10
11
13
1 32
A
A
7
59
12
Section A - A
D0400686
4 65
1
32
1. Rod
2. Cylinder
3. Piston
4. Locking pad
5. Sliding pad
6. Nut
72. ARM CYLINDER (FOR SIDE DIGGING BOOM CYLINDER)
SIDE DIGGING BOOM CYLINDER
JIG ARM CYLINDER
10-52 WB70A-1
1. Head bushing
2. Piston rod
3. Cylinder head
4. Cylinder
5. Piston
6. Piston ring
7. Guide ring
8. Bearing
9. Snap ring
1. Head bushing
2. Piston rod
3. Ring nut
4. Cylinder head
5. Oil seal
6. Cylinder
7. Piston
8. Piston ring
9. Dowel pin
10. Bottom bushing
D0400679
94 65 7 81 32
43 5 6 7 8 9 1021
D0400681
D0400691
4 651 32
1. Piston rod
2. Cylinder head
3. Cylinder
4. Piston
5. Guide ring
6. Piston ring
73. SPECIFICATIONS
Cylinder Boom
Arm
Bucket
Boom
swingWith standard
boom
With side
digging boom
Piston rod size 50 50 50 45 45
Bore 95 95 95 85 95
Stroke 895 670 670 650 208
Max. stroke 2090 1645 1665 1600 292
Min. stroke 1195 975 995 950 84
Width across flats
of piston nut
65 65 65 65 50
SPECIFICATIONS
Cylinders Outrigger
Backframe
locking
Side digging
boom
Jig arm
Piston rod size 35 33 40 35
Bore 60 92 80 60
Stroke 635 4 220 720
Max. stroke 1605 Ð 740 1690
Min. stroke 970 Ð 520 970
Width across flats
of piston nut
46 Ð 46 46
10-53WB70A-1
75. CONTROL LEVER POSITION
Bucket dump
Bucket curl
Boom lower
Boom raise
Boom R.H. swing
Boom L.H. swing
Arm out
Arm in
R.H. outrigger lower
R.H. outrigger raise
L.H. outrigger lower
L.H. outrigger raise
1. R.H. work equipment control lever
2. R.H. outrigger control lever
3. L.H. work equipment control lever
4. L.H. outrigger control lever
5. Backframe locking lever
6. Backhoe locking lever
1
2
3
4
5
6
7
8
9
10
11
12
BACKHOE CONTROL LEVER
10-55WB70A-1
D0400772
1
2
3
4
5
6
8
7
10
11
9
4
6
5
1
3
2
12
76. SOLENOID VALVE BLOCK ST1 (FOR KNUCKLE LOCKING, AXLE LOCKING, FAST-LOW SPEED CONTROL)
a. P Port - From pump P1 (G Port)
b. B2 Port - To bounce locking cylinder
(Bottom side)
c. A4 Port - To transmission (B Port)
d. A3 Port - To transmission (A Port)
e. A1 Port - To rear differential (B Port)
f. A2 Port - To bounce locking cylinder (Head
side)
g. T Port - To hydraulic oil tank and from in-
ching valve (B Port)
CONNECTOR
1. EV4 Bounce locking
2. EV3 Differential locking
3. EV2 Low speed
4. EV1 High speed
SOLENOID VALVE
10-56 WB70A-1
D0400738
41 32
b
f e d cg
a
89. Normal or standard technical data ................... 2
Special tools........................................... 16
Measuring engine speed ............................. 17
Adjusting valve clearance ............................ 18
Measuring compression pressure ................... 19
Testing and adjusting fuel injection timing ......... 20
Checking and tightening the fan - belt .............. 21
Measuring accelerator pedal operating
force and accelerator lever .......................... 22
Adjusting inch pedal travel........................... 23
Adjusting brake pedal travel ......................... 24
Testing frame articulation clearance ................ 25
Air bleeding - releasing residual pressure .......... 26
Checking and setting pressure in the attachments
hydraulic circuit ....................................... 30
Testing and adjusting hydrostatic transmission ....34
Testing and adjusting travel maximum speed
(universal joint) ........................................40
Testing travel motor leakage .........................41
Adjusting transmission sensor .......................42
Testing priority valve operation ......................43
Testing and setting steering control system
pressure................................................44
Testing steering cylinder leakage....................45
Testing brake system .................................46
Adjusting parking brake lever ........................48
Brake disc clearance adjustment ....................49
Checking wear in the brake disks ...................49
Analysis of causes hydraulic drifts...................50
Adjusting of cylinder draft of backframe locking ...55
TESTING AND ADJUSTMENTS
20-1
When carrying out controls, adjustments or analyses for troubleshooting, park the machine on firm, level
ground. Apply all the machine safety devices and use blocks to prevent any machine movement.
When more than one person is engaged in the work, use the prescribed notices that indicate that the machine
is undergoing maintenance. Do not allow any unauthorised persons to remain in the vicinity.
When checking the level of the cooling liquid, wait until this liquid has cooled. If the radiator cap is removed
while the liquid is still hot and under pressure, it may cause severe burns.
Take great care not to get entangled in moving parts (fan, alternator belt or any of the rotating elements).
WB70A-1
90. Machine model WB70A-1
Engine 4D98E-1FA
Check item Test conditions Unit Standard
value
Permissible
value
Engine speed
High idling
Low idling
Set speed
rpm
rpm
rpm
2700w50
900w50
Ð
Ð
Ð
Ð
Exhaust gas
colour
Sudden acceleration
At high idling speed
Index
Bosch
0.9
0.5
1.1
0.6
Valve clearance
Intake valve (20ëC)
Exhaust valve (20ëC)
mm
mm
0.20
0.20
Ð
Ð
Compression
pressure
(SAE30 oil)
Oil temperature 69 ± 72ëC
(Engine speed)
kg/cm2
(rpm)
35w1
(250)
28w1
(250)
Blow - by
pressure
(SAE30 oil)
Water temperature in operating range
At high idling speed
mm H2O
Ð
Ð
Ð
Ð
Engine oil
pressure
Max idling (in cold state)
At set speed
At low idling
kg/cm2
kg/cm2
kg/cm2
Max. 6
3 ± 4
Min. 0.6
Ð
Ð
Ð
Oil temperature Entire speed range ëC 90ë Max. 120
Fuel injection
timing B.T.D.C. degrees 10 ± 12 Ð
Fan - belt
tension
Deflection when pressed with finge force
of approx. 10 kg mm 10 ± 15 Ð
NORMAL OR STANDARD TECHNICAL DATA
. FOR ENGINE
20-2 WB70A-1
91. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
With piston pump
at max. pressure
. Hydraulic oil temperature: 55 ± 65 ëC.
. Engine oil temperature cooling circuit:
in the limits
. Raised machine and working brakes
applied in 2nd
gear
rpm
2620w50 Min. 2550
With piston pump
and steering pump
at max. pressure
. Hydraulic oil temperature: 55 ± 65 ëC.
. Engine oil temperature cooling circuit:
in the limits
. Raised machine and working brakes
applied in 2nd
gear and total steering
2600w50 Min. 2500
With equipment
pump at
max. pressure
. Hydraulic oil temperature: 55 ± 65 ëC.
. Engine oil temperature cooling circuit:
in the limits
. Front bucket curled
2550w50 Min. 2450
All controls
(front bucket
and backhoe)
mm
, a b , a b
45 7 7 45 7 7
Front bucket tilt
lever control . Engine stopped
. At the centre
of knob lever
. Valve reading
at the end of
working stroke
. Attachments
on the ground
Neutral Raise
Lower
mm
100 90 ± 110
Front bucket control
lever Neutral Dump
Curled 100 90 ± 110
Additional
attachments
control lever
Neutral
R.H.
side
L.H. side
100 75 ± 125
Boom control
lever Neutral Raise
Lower 80 70 ± 90
Arm control
lever Neutral Opening
Closing 80 70 ± 90
Bucket control
lever Neutral Opening
Curled 80 70 ± 90
Boom swing control
lever Neutral Right
Left 80 70 ± 90
Outriggers control
lever Neutral Up
Down 50 40 ± 60
Fuel control
lever Min. Max. 220 200 ± 400
Jig arm control
pedal Neutral Out
In 25 15 ± 35
Side digging boom
control pedal Neutral Right
Left 25 15 ± 35
Hammer control
pedal Neutral Ð
Max. 25 15 ± 35
. FOR MACHINE
20-3WB70A-1
EnginespeedControlvalveTravelofleversandpedals
RKZ03870
a
ഞ
b
92. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
Value
Accelerator pedal
. Engine stopped
. At the centre
of lever knob
. Reading of
value at the
end of working
stroke
. Attachments
on ground
Min. Max.
mm
70 63 ± 77
Inch control pedal 0 Applied 100 90 ± 110
Backhoe locking
lever Lock Unlock De-
grees 90 ±
Wheel swing Right
Left
Left
Right Rpm 3.5 3.2 ± 3.8
Parking brake
lever Released Stopped Clicks 7 10
Front bucket tilt lever
control
. Engine speed : Max.
. Oil temperature: 55 ± 65ëC
. Tool connection at the centre of knob
(for levers)
. Tool connection on edge
(for pedals)
kg
2.5 1.9 ± 3.1
Front bucket control
lever 2.5 1.9 ± 3.1
Additional
attachments
control lever
5 3.8 ± 6.2
Boom control
lever 2 1.5 ± 2.5
Arm control
lever 2 1.5 ± 2.5
Bucket control lever 2 1.5 ± 2.5
Boom swing control lever 2 1.5 ± 2.5
Outriggers control
lever 5 3.8 ± 6.2
Fuel control lever 3 2.5 ± 3.5
Jig arm control
pedal 5 3.8 ± 6.2
Side digging boom
control pedal 5 3.8 ± 6.2
Hammer control
pedal 5 3.8 ± 6.2
Accelerator pedal 8 6 ± 10
Brake pedal 45 Max. 60
Inch control pedal 8 6 ± 10
Wheel swing 1.1 1.0 ± 1.2
. FOR MACHINE
20-4 WB70A-1
TravelofleversandpedalsForceforleversandpedalsoperation
93. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
3-Spool control valve
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
. Check one circuit at the time
bar
200w5 200w7
6-7-8-Spool control valve 190w5 190w7
Steering unit 160w5 160w7
Front bucket
(curled) ]
. Engine speed: max.
. Oil temperature: 55 ± 65ëC
. Check one circuit at a time
] Check on the test bench
bar
270w5 270w7
Front bucket (dump) 195w5 195w7
Additional
attachments
(right - left)
170w5 170w7
Boom (raising) ] 270w5 270w7
Boom (lowering) 210w5 210w7
Arm (in) 210w5 210w7
Bucket (curled) 210w5 210w7
Side digging boom
(right - left) 270w5 270w7
Hammer (delivery) 160w5 160w7
Steering unit 230w5 230w7
Cut pressure valve 440w5 440w7
. FOR MACHINE
20-5WB70A-1
Mainvalve
pressurePressuresofsecondaryvalvescircuits
94. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Travel motor
swing speed
(no-load)
Measuring posture
. Engine speed: 2200w10 rpm
. Oil temperature: 55 ± 65ëC
. Machine with raised wheels
. Oscillating locking dowel applied
. Check speed of the transmission
shaft with 2nd
gear
rpm
2750w50 2600 Min.
1520w50 1450v1550
Travel speed
Measuring posture
. Road circulation configuration
. Engine speed max.
. Oil temperature 55 ± 65ëC
. On level ground
. 2nd
gear
. Move for at least 20 meters and
check the necessary time to cover
50 meters.
sec.
4.7w0.3 4.2v5.2
10w0.5 9.0v11
Leakage from
travel motor
Measuring posture
. Engine speed: 2000 rpm
. Oil temperature:: 55 ± 65ëC
. Machine with raised wheels
. Oscillating locking dowel applied
. Working brakes applied
. 2nd
gear
. After 30 seconds start the check for the
following minute.
,/min ± ±
. FOR MACHINE
20-6 WB70A-1
StandardTUV20km/hStandard
Travel
D0401008BlocchiBlocks
D0401007
D0401008BlocchiBlocks
TUV20km/h
95. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Complete working
equipment
(Tip lowering of
bucket teeth )
Measuring posture
. In this position check in feedback of each
cylinder and the leakage with applied
load on the tip of bucket teeth.
. Ground level.
. Bucket: normal load (1250 kg)
. Engine stopped
. Oil temperature: 55 ± 65ëC
. Check measures as soon as engine
stops.
. Check changes every 5 min. and the total
change in 15 min.
mm
Max. 250 Max. 300
Cylinders
(cylinder in)
Max. 40 Max. 50
Bucket cylinder
(cylinder in)
Max. 15 Max. 20
Complete working
equipment
(Tip lowering of
bucket teeth)
Measuring posture
. In this position check the extension of
each cylinder and the leakage with nor-
mal load on the bucket.
. On level ground.
. Bucket : normal load (250 kg)
. Engine stopped
. Oil temperature: 55 ± 65ëC
. Check measures as soon as engine
stops.
. Check changes every 5 min. and the total
change in 15 min.
mm
Max. 300 Max. 400
Boom cylinders
(cylinder out)
Max. 35 Max. 95
Arm cylinders
(cylinder out)
Max. 12 Max. 16
Bucket cylinder
(cylinder in)
Max. 10 Max. 14
. FOR MACHINE
20-7WB70A-1
HydraulicdriftworkingequipmentBackhoe
D0401010
~10°
D0401025
1m
96. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Boom swing
. Oil temperature: 55 ± 65ëC
. Backhoe balanced on the guides, bucket
in transport condition.
. Arm and bucket cylinder in. Put the buck-
et link pin at 1 meter from ground and
swing at end of boom stroke in one of
the two direction.
. Move the machine on a chute of 15ë and
apply the parking brake.
. Stop the engine and, after 1 minute,
check the cylinder feed back opposite
to the boom every 5 min. for a total of
15 minutes.
H Make the test for each swing direction.
mm
Max. 15
(each side) Max. 20
Outriggers
. Oil temperature: 55 ± 65ëC
. By pass the safety valves.
. Balanced backhoe.
. Boom and arm cylinders in, bucket cylin-
der out
. Outriggers at maximum extension.
. Engine stopped.
. Check the frame lowering for each side
every 5 min. for a total of 15 minutes
Max. 20 Max. 20
. FOR MACHINE
20-8 WB70A-1
Frontbucket
Hydraulicdriftworkingequipment
D0401011
D0401012
97. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Boom
. Engine: Max. speed
. Oil temperature: 55 ± 65ëC
. Leaking check: on the cylinder opposite
side to the pressure one
H Check 1 cylinder at a time.
H For tilt front bucket, for steering and for
swing: check the two cylinders sepa-
rately.
mm
1.8
(each cylinder) Max. 6
Bucket 1.5
(each cylinder) Max. 5
Steering ± ±
Boom 3.0 Max. 10
Arm 2.8 Max. 9
Bucket 2.2 Max. 8
Boom swing 3.0 Max. 10
Outriggers 3.2 Max. 12
Side digging boom 2.0 Max. 7
Jig arm 1.5 Max. 5
. FOR MACHINE
20-9WB70A-1
Backhoe
CylinderleakingBackhoe
98. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Tilt lever front
bucket
Bucket on level ground
Cylinders extended out
Measuring posture
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
sec.
4.5 4.2v4.8
3.0 2.8v3.2
Front bucket
Cylinder out
Cylinder in
Measuring posture
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
1.8 1.7v1.9
2.1 2.0v2.2
Boom
Teeth bucket on level
ground
Cylinder in
Measuring posture
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
. Backhoe balanced
2.9 2.7v3.1
2.3 2.1v2.5
Arm
Cylinder in
Cylinder out
Measuring posture
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
. Backhoe balanced
4.5 4.2v4.8
3.5 3.3v3.7
Bucket
Cylinder in
Cylinder out
Measuring posture
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
. Backhoe balanced
3.5 3.3v3.7
2.9 2.7v3.1
. FOR MACHINE
20-10 WB70A-1
Frontbucket
WorkequipmentspeedBackhoe
FrontbucketDumpCurledOpeningClosingLoweredRaisedDumpCurledLowered
D0401013
D0401014
D0401015
D0401016
D0401017
99. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Boom swing
Left end travel
Right end travel
Measuring posture
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
. Backhoe balanced
. Arm vertical
sec.
3.5 3.3v3.7
3.5 3.3v3.7
Outriggers
All extended
All raised
Measuring posture
. Engine speed: Max.
. Oil temperature: 55 ± 65ëC
. Backhoe balanced
. Dowel joint locking: applied
. Front bucket on level ground
. Rear wheels raised
3.0 2.5v3.5
3.0 2.5v3.5
. FOR MACHINE
20-11WB70A-1
Raised
Workequipmentspeed
BackhoeLoweringLiftingLeft
D0401021
D0401022
100. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Tilt lever front
bucket
Measuring posture
. Engine speed: Min.
. Oil temperature: 55 ± 65ëC
. Check the time necessary to lift bucket
from level ground.
sec.
0 Max. 2
Boom
Measuring posture
. Engine speed: Min.
. Oil temperature: 55 ± 65ëC
. With attachments fully extended, lower
the boom and check the necessary time
from the beginning of machine lifting until
bucket is on level ground.
0 Max. 2
Arm
Measuring posture
. Engine speed: Min.
. Oil temperature: 55 ± 65ëC
. Put boom at 45ë, open completely the
arm with curled bucket. Extend arm cylin-
der and check the time passing between
arm stop at dead centre and the restart
movement.
0 Max. 2
. FOR MACHINE
20-12 WB70A-1
Right
Workequipment
D0401018
D0401019
D0401020
45°
101. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
Bucket
Measuring posture
. Engine speed: Min.
. Oil temperature: 55 ± 65ëC
. Put arm in horizontal position. Tilt back
bucket cylinder an then extend it.
Check the time passing between bucket
stop at dead centre and the restart move-
ment.
sec.
0 Max. 2
Outriggers
Measuring posture
. Engine speed: Min.
. Oil temperature: 55 ± 65ëC
. Boom, arm and bucket fully retracted and
putted in machine centre position
. Check the time necessary for outriggers
to raise the machine from when they lean
on level ground.
H Check each outrigger at a time.
0 Max. 2
. FOR MACHINE
20-13WB70A-1
Timelags
Workequipment
D0401023
D0401024
102. Machine model WB70A-1
Classi-
fication Check item Test conditions Unit Standard
value
Permissible
value
P3 gear pump
(26.5 cc/rev)
(R=1:1.2)
. Engine: 2000 rpm
. Oil temperature: 55 ± 65ëC
. Measure the flow rate at
50 - 100 - 200 bar
50 bar
,/min
100 bar
200 bar
P2 gear pump
(14.2 cc/rev)
. Engine: 2000 rpm
. Oil temperature: 55 ± 65ëC
. Measure the flow rate at
50 - 100 - 160 bar
50 bar
100 bar
160 bar
P1 piston pump
. Engine: 2000 rpm
. Oil temperature: 55 ± 65ëC
. Check the speed/pressure ratio
See following diagram
. FOR MACHINE
20-14 WB70A-1
Timelags
104. Measurement check point Symbol Code Name Q.ty Remarks
Valve clearance A 1 Commercially
available Feeler gauge 1 Ð
Compression pressure B
1 ATR800090 Compression gauge 1 0-70 kg/cm2
2 ATR800130 Adapter 1 Ð
Engine speed C
1 ATR800070 Multiscale tachometer 1 20 - 4000 rpm
2 ATR800060 Stroboscopic tachometer 1 6 - 30000 rpm
Oil and water temperature D 1 Commercially
available Digital thermometer 1 ± 50 - 1200 ëC
Hydraulic pressure
and flow rates E
1 ATR800010 Pressure gauge 2 Full scale 600 bar
2 ATR800140 Pressure gauge 1 Full scale 400 bar
3 ATR800150 Pressure gauge 1 Full scale 250 bar
4 ATR800160 Pressure gauge 1 Full scale 100 bar
5 ATR800170 Pressure gauge 3 Full scale 60 bar
Pump adjusting
piston position F 1 ATR201270 Connection between
chambers 1 Ð
Disc brake thickness G 1 ATR500930 Feeler gauge 1 2313 (CK)
Brake performance H 1 ATR201280 Tool for circuit selection 1 Ð
SPECIAL TOOLS
20-16 WB70A-1
105. When checking engine speed, be careful not to
touch high temperature parts and not to get caught
in rotating parts.
H Check speed when following condition are reached:
. Engine water cooling temperature: 69.5 ± 72.5 ëC.
. Hydraulic oil temperature: 55 ± 60 ëC.
1 - Install and connect C1 tachometer.
H If using C2 stroboscopic tachometer, mark a light
notch on, engine pulley for an easier reading.
2 - Start engine and check:
. Low idling speed without load (accelerator pedal
released and hand accelerator lever (1) in «mini-
mum» position).
. High idling speed without load (accelerator pedal
at the travel end or hand accelerator pedal (1) at
end travel).
H Low idling speed: 900w50 rpm
H High idling speed: 2700w50 rpm
H If low and high idling speed with engine without
load are not within permissible value, before
going on with other operations, check accelerator
pedal stoppers and wiring sheathings (see « AC-
CELERATOR LEVER ADJUSTING»).
20-17
MEASURING ENGINE SPEED
TESTING AND ADJUSTMENT MEASURING ENGINE SPEED
WB70A-1
F0401180
C1
F0401181
MIN.
MAX
1 1
106. H Adjust clearance between valves and rocker levers as
follows:
Unit: mm
At cold
engine
Intake valve Exhaust valve
0.20 0.20
H Firing order: 1-3-4-2-1.....
H Normal rotation sense: counterclockwise from fly-
wheel
. Adjusting procedure
1 - Remove valves cover (1).
2 - Rotate crankshaft in normal direction as long as
cylinder piston to be checked is at compression
Top Dead Center. (PMS).
H In this position intake and exhaust valves are
closed.
3 - Loose lock nut (2) and unscrew tappet (3) of about
1 turn.
H Check that valve insert (4) is laying flat on
valve stem and that it is not worn askew.
1 - If valve inserts (4) are damaged, replaced
them with new ones.
2 - Make sure that inserts feet and lay flat on
valve stem.
4 - Connect A1 feeler gauge between insert and rock-
er lever to adjust; rotate the tappet (3) until touch-
ing A1 feeler gauge.
Tight tappet (3) with lock nut (2).
H After tightening the lock nut, check the clear-
ance again.
5 - Adjust with same procedures second cylinder
valve and repeat same operation for the other cy-
linders, according to the firing order.
. Cover valves installation
1 - Check condition of cover valves (1), gasket (5), O-
Rings (6) and lock nuts (7); clean carefully contact
surface on cylinder head.
2 - Install valves cover (1), fit O-Rings (6) and lock
nuts (7).
Cover lock nut: 25w3 Nm
20-18
ADJUSTING VALVE CLEARANCE
TESTING AND ADJUSTMENT ADJUSTING VALVE CLEARANCE
WB70A-1
F0401182
1
D0400882 4
4
2
3
SI NOYES NO
3 2
A1
D0400893
D0400891
6
5
71
107. . When measuring the compression pressure be
careful not to get caught in cooling fan, in the al-
ternator belt or in other rotating parts.
. Check all cylinders.
H Test condition:
. Engine: at operating temperature
. Hydraulic oil: 55 ± 60 ëC
. Battery: at full charge
. Valve clearance:
adjusted (see «ADJUSTING VALVE»)
1 - Disconnect high pressure pipe (1).
2 - Remove nozzle holder assembly (2) of cylinder to be
checked.
3 - Disconnect connector (3) of fuel cut-off solenoid valve
(4).
4 - Crank engine with starting motor.
5 - Install B2 adapter and connect B1 pressure gauge
H Check that seal is installed in the adapter and that
it is not damaged.
6 - Crank engine with starting motor and measure com-
pression pressure.
H Measure the compression pressure at the point
where the pressure gauge indicator remains stea-
dy.
H When measuring the compression pressure,
check also engine speed with C2 stroboscopic
tachometer; if speed is not within the specified
range, refer to diagram.
H Compression value:
Normal: 35w1 kg/cm2
at 250 rpm
Minimum permissible: 28w1 kg/cm2
at 250 rpm
H Difference between cylinders: 2 ± 3 kg/cm2
7 - After measuring, install the nozzle holder assembly
(2), connect high pressure pipe, feedback pipe and
connector (3).
Nozzle holder collar bolts: 6.9 ± 8.8 Nm
High pressure union: 19.6 ± 24.5 Nm
20-19
MEASURING COMPRESSION PRESSURE
TESTING AND ADJUSTMENT MEASURING COMPRESSION PRESSURE
WB70A-1
F0401183
1
2
F0401184
3
4
F0401185
B1
B2
D0400881
35
40
30
25
20
200 250 300 350 400
Velocità motore (giri/min)
Pressionedicompressione
(kg/cm2
)
Compressionpressure
(kg/cm2
)
Engine speed (rpm)
108. H Check fuel injection timing of N.1 cylinder by
means of N.1 delivery valve of injection pump.
H Cylinders are numbered 1-2-3-4 starting from fly-
wheel side.
1 - Rotate crankshaft using engine pulley and put N. 1cy-
linder piston at top dead centre (PMS).
H Top dead centre (PMS) is shown by notch (4) on
pulley (1) positioned on «zero» of the scale (5)
and by closing of both cylinder N. 1 valves.
H If the notch (4) of pulley (1) is in «zero» position on
the scale (5) but cylinders N. 1 valves are not
closed, rotate the crankshaft of 1 turn.
H After recognition of PMS, rotate the crankshaft in
counterclockwise direction (from pulley side view)
of about 90ë.
2 - Disconnect all cylinder delivery pipes (2) from injec-
tion pump.
3 - Move externally the stop engine lever (3) and fix posi-
tion with a temporary string.
4 - Rotate crankshaft slowly in clockwise direction from
pulley side view, checking fuel level into the N. 1 de-
livery of injection pump.
Stop pulley (1) rotation as soon as fuel level starts to
increase.
5 - Check notch (4) position on crankshaft pulley (1) com-
pared with scale (5); reading value corresponds to an-
gle of fuel injection timing.
H Standard fuel injection timing: ±10*12ë
6 - If injection timing is not on standard value, rotate in-
jection pump (6) toward external or toward engine
after loosening pump nuts (7) (quantity 4) and pump
lock nuts (8) fixing the bracket (9) to injection pump.
. To RETARD injection, rotate pump (6) toward ex-
ternal.
. To ADVANCE injection, rotate pump (6) toward
cylinders block.
7 - Tight the pump lock nuts (7) at cylinder block and
pump lock nut (8) at bracket (9).
Nuts: 34.2 ± 44.1 Nm
Bracket lock nut: 44.1 ± 53.9 Nm
8 - Connect fuel delivery pipes (2) to pump.
Delivery pipes unions: 19.6 ± 24.5 Nm
9 - Release the stop engine lever (3) and carry out air
bleeding.
20-20
TESTING AND ADJUSTING FUEL INJECTION TIMING
TESTING AND ADJUSTMENT TESTING AND ADJUSTING FUEL INJECTION TIMING
WB70A-1
F0401186
Nº1
2
6
7
8 9
3
D0400892
Volano
Cilindro n°1N. 1 Cylinder
Flywheel
F0401513
1
45
4 5
D0401031
Raccordo
N°1
Livello
N. 1 Union
Level
109. 1. Tension check
1 - Push fan belt (1) at midway point between alterna-
tor (2) and pulley (3) operating water pump; check
the deflection.
With a pressure of 10 kg (98 Nm), deflection
should be of 10 ± 15 mm; if this value is not
reached, tension fan belt.
H With new belt, deflection must be of 7 ± 9 mm
2 . Fan belt tension
1 - Loosen mounting bolt (4) of the alternator (2) and
mounting bolt (5) of adjustment plate.
2 - Rotate the alternator (2) to give correct tension to
fan belt (1) and tighten mounting bolts (4) and (5).
3 - Check fan belt (1) tension.
H If belt has been replaced, check tension again
after about 20 operating hours.
Alternator mounting bolts on timing cover:
44.1 ± 53.9 Nm
Bracket clamping bolts: 22.5 ± 28.4 Nm
20-21
CHECKING AND TIGHTENING THE FAN - BELT
TESTING AND ADJUSTMENT CHECKING AND TIGHTENING THE FAN - BELT
WB70A-1
F0401187
1
2
3
F0401188
4
5
D0400883
10Ϭ15 mm
Alternatore
Puleggia
albero motore
Puleggia pompa
acqua
Water pump
pulley
Crankshaft
pulley
Alternator
10 ± 15 mm
110. H Work condition:
. Engine stopped
. Low and high idling speed: within permissible va-
lue.
1 - Remove lower cover (1) and approach to rods con-
nected to accelerator lever.
2 - Make sure that accelerator pedal is fully raised.
3 - Check that accelerator lever (2) is in contact with low
idling speed adjusting screw (3).
4 - Adjust nut (4) and lock nut (5) of accelerator pedal
cables and hand accelerator at a distance of 0.2±
0.3 mm from lever (6).
5 - Push accelerator pedal until accelerator lever (2) con-
tacts the high idling adjusting screw (7).
6 - Adjust the end travel stopper (8) of accelerator pedal
(9) in this position and lock it with nut (10).
7 - Release the accelerator pedal.
8 - Operate hand accelerator lever and check that accel-
erator lever (2) contacts the high idling adjusting
screw (7).
20-22
MEASURING ACCELERATOR PEDAL OPERATING
FORCE AND ACCELERATOR LEVER
TESTING AND ADJUSTMENT
MEASURING ACCELERATOR PEDAL OPERATING
FORCE AND ACCELERATOR LEVER
WB70A-1
F0401189
1
F0401191
2
3 7
F0401190
4 5
6
4 5
F0401192
8
9
10
