3. 0-6
NOTE:
This Manual is prepared as a technical material in
which the information necessary for the maintenance
and repairing services of our hydraulic excavators are
collected, and is categorized into 7 Chapters, Specifica-
tion, Maintenance, System, Disassembly, Trouble-
shooting, Engine, and Installation Procedures for
Optional Attachment.
• The Chapter "Specification" describes the specifi-
cations for entire machine and material, which are
instructive for replacement and repairing of attach-
ments.
• The Chapter "Maintenance" describes the material,
which is helpful for maintenance service and adjust-
ments for entire machine.
• The Chapter "System" describes the operating sys-
tem like hydraulic system, electric system, compo-
nents, and so on.
• The Chapter "Disassembly" describes the removal
and installing of assembly mounted on the upper
structure and undercarriage, and the assembling
and disassembling of the associated hydraulic
equipment.
• The Chapter "Troubleshooting" describes how to
find the fault equipment.
• The Chapter "Engine" describes the engines mak-
ing use of the "Maintenance Manual" provided by
the suppliers.
• The Chapter "Installation Procedures for Optional
Attachment" describes the supplements added on
request as required.
This Manual may be properly revised due to the im-
provement of products, modification of specifications,
etc. And there are cases where the system on actual
machine and a part of the contents of this manual may
differ due to the variations of specification by countries.
For the section in which the description is hardly under-
stood, contact our distributor.
The number is assigned to every part handled in this
Manual on account of the description, but the parts,
which cannot be supplied as service parts are con-
tained. Therefore, the order must be placed with re-
spective formal number with due confirmation on the
Parts Manual for applicable machine.
4. 33. UPPER SLEWING STRUCTURE
33-60
33.1.18 SWING MOTOR UNIT
33.1.18.1 PREPARATION FOR REMOVING
(1) Park machine on firm level ground and place attachment on ground.
(2) Remove bracket (B9) for engine bonnet gas damper. [See 33.1.4.2.(4)]
(3) Remove top cover of swing motor and guard assy (B3), (B5), (B10), (B2), (B7), (B8) and (B1). [See 33.1.4.2.(6)]
(4) Operate the switch on gauge cluster and select the pressure release mode, and then release the inner pressure
in circuit by operating control lever. (See 22.11 HYDRAULIC SYSTEM PRESSURE DRAINING(RELEASING)
CIRCUIT)
(5) Bleed air from the hydraulic oil tank and attach to each hose a tag showing port name and other information.
33.1.18.2 REMOVAL
(1) Remove hose.
1. Remove hose (B3X) from the connector in the makeup port Mu.
Tools: Spanner: 36mm
2. Remove hose (B1), (B2) from the elbow in the drain port Dr.
Tools: Spanner: 27mm
3. Remove hose (B4) from the elbow of the PG port (For swing parking brake)
Tools: Spanner: 19mm
4. Remove 2 hoses (B1X), (B2X) from the connectors of the A, B port.
Tools: Spanner: 36mm
Put in plugs PF3/4, PF1/2, and PF1/4 into the removed ports.
Removing swing unit piping
B2X
B1X
A
B
C/V
AS
C/V
BS
B4
S/V
A2
PG
Dr
MU
C/V
T3
TANK
B1
B2
S/J
E
5. 33. UPPER SLEWING STRUCTURE
33-61
33
(2) Removing the swing unit
33.1.18.3 PREPARATION FOR INSTALL
(1) Clean mating surfaces of swing motor unit and upper frame.
Tools : spatula, wash oil
(2) Apply Loctite #515 on entire mounting surface of swing motor unit.
1. Loosen nut (9).
2. Remove 13 capscrews (7) M20X55.
Tools: Socket: 30mm
3. Remove two plastic caps (6) M12 at the top of the
swing motor and install eye bolts.
Tools: Flat-blade screwdriver
4. Put a wire sling in the eye bolts and remove the
swing motor unit.
Weight of swing motor unit ;
Approx. 191kg (421 lbs) (Include reduction assy)
Removing swing unit
9
7
6
6. 33. UPPER SLEWING STRUCTURE
33-62
33.1.18.4 INSTALLATION
Confirm the installing direction of swing motor; install the swing motor unit in the reverse order of disassembly.
Installation procedure of cap (5)
- Wrap seal tape around the thread portion of tube side 2.5 times.
- Tighten the cap until it could not be turned by hand.
- Screw in the cap additional 2.5 times by wrench.
33.1.18.5 PREPARATION FOR DRIVE
(1) Before starting operation, check that gear oil #90 (API grade GL-4) level of swing reduction is sufficient.
Amount of oil : 2.7L (0.71gal)
(2) When starting operation, operate motor in low idling and at low speed for several minutes, and check it for
possible oil leak and noise.
(1) Tighten 13 capscrews (7) M20X55.
Tools: Socket: 30mm
Tightening torque: 539N-m (400 lbf-ft)
Apply Loctite #262
(2) Fill inside from motor drain port to casing with
hydraulic oil before piping for drain
Installing swing motor unit
CAP
CAP
NUT
Tightening torque
46.1 N.m (34 lbf.ft)
Fix drain hose with
the plug at the end
of drain hose of UPP
frame bottom plate.
TUBE
LEVEL GAUGE
LEVEL GAUGE
Coil the seal tape
at the screw.
Tightening torque
69.1 N.m (51 lbf.ft)
Coil the seal tape
at the parts of screw
both ends of tube.
Tightening torque
108 N.m (80 lbf.ft)
Tightening torque :54.9 N.m (40 lbf.ft)
or tighten follow the process "NOTE".
FORWARD
7
5
1
Tightening torque
539 N.m (400 lbf.ft)
13 Places
TUBE
TUBE
Detail of tube mount
OIL LEVEL
Detail of swing motor
unit assy mount
Apply to all round of mounteing
face for motor. swing.
7. 33. UPPER SLEWING STRUCTURE
33-63
33
33.1.19 SWIVEL JOINT
33.1.19.1 PREPARATION FOR REMOVING
Remove boom piping hose
33.1.19.2 REMOVAL
(1) Remove travel motor hose and tube
1. Remove 2 hoses (A16). (E port : PF1/2)
Tools: Spanner: 27mm, Tightening torque : 78.5N-m (58 lbf-ft)
2. Remove tubes (A1), (A2). (C, D port : PF1)
Tools: Spanner: 41mm, Tightening torque : 275N-m (203 lbf-ft)
3. Remove tubes (A3), (A4). (A, B port : PF1)
Tools: Spanner: 41mm, Tightening torque : 275N-m (203 lbf-ft)
4. Remove 2 hoses (A7). (F port : PF1/4)
Tools: Spanner: 19mm, Tightening torque : 29.4N-m (22 lbf-f)
Removing piping (lower side)
A3
A1
B2
A16
B2
A7
A7
A16
A4
A2
C
A
E
F
F
B
D
E
SWIVEL JOINT
(LH) (RH)
P2 (LOWER)
REVERSE
P1 (UPPER)
FORWARD
(TRAVEL MOTOR)
FORWARD
P1 (LOWER)
REVERSE
P2 (UPPER)
(TRAVEL MOTOR)
8. 33. UPPER SLEWING STRUCTURE
33-64
(2) Disconnecting the hoses on the top part of swivel joint
(3) Remove whirl-stop of swivel joint.
(4) Remove joint for piping (See Fig."Removing piping (lower side)")
1. Remove 2 connectors (B2). (F port)
2. Remove connector (A16) (F port) for travel 2-speed change over. (PF1/4)
Tools: Spanner: 19mm
(5) Remove seal (C1)
1. Remove drain hoses (B1). (E port : PF1/2)
Tools: Spanner: 27mm
Tightening torque: 78N-m (58 lbf-ft)
2. Remove hoses (A2), (A7).
(C, D port : 1-3/16-12UN)
Tools: Spanner: 36mm
Tightening torque: 177N-m (130 lbf-ft)
3. Remove hoses (A4), (A3).
(A, B port : 1-3/16-12UN)
Tools: Spanner: 36mm
Tightening torque: 177N-m (130 lbf-ft)
4. Remove hose (A8).
(Travel 2-speed change over port : PF1/4)
Tools: Spanner: 19mm
Tightening torque: 29N-m (21 lbf-ft)
Disconnecting the hoses on the top part of swivel
joint
1. Loosen the nut (C11) M24.
2. Remove a capscrew (C10) M24X140.
Tools: Spanner: 36mm
Removing whirl-stop nut & the capscrew
1. Remove 6 sems bolts (B8) M10X25.
Tools: Socket: 17mm
2. Remove clip (C3).
Tools: Flat-blade screwdriver
3. Remove seal (C1).
Removing seal (C1)
A4
A2
D
F
B
E
A
C
C/V
Br
C/V
BL
C/V
ALS/V
A3
C/V
Ar
A3
A8
A16
A7
B1
S/M
Dr
C11 C10
15mm
Tightening torque
157N.m (116 lbf.ft)
At assembling,
this distance
should be 15mm (0.591in).
C3
C4
C2
C1
Tightening torque
2.0N.m (1.47 lbf.ft)
Tightening torque
14.7N.m (11 lbf.ft)
To prevent from
entering water,
apply Loctite 572
or 577 around
this plate (C2).
Before mounting the seal
(C1), apply adhesive to the
adhering surface of S/J
and the upper frame.
9. 33. UPPER SLEWING STRUCTURE
33-65
33
(6) Remove capscrew for installation
(7) Slinging the swivel joint
Weight: Approx. 28kg (62 lbs)
33.1.19.3 INSTALLATION
Attach eye bolt, lift it up temporarily, and remove 3
capscrews (C2) M12X25.
Tools: Socket: 19mm
(See 11.7 SPECIAL TOOLS No.9 Plug)
Removing sems bolts for installation
(1) Installing is done in the reverse order of removing.
Piping tightening torque
(2) Check for oil leak and the hydraulic oil level.
(3) Check for operating.
C2
CAPSCREW
M12 25
Loctite #262
T=108N.m
(80 lbf.ft)
C1
SWIVEL JOINT
LOWER FRAME
EYE BOLT
O-ring type
Connector
Hydraulic hose
Tightening torque N.m (lbf.ft)
Tool.
HEX
Size
PF
1/4
3/8
1/2
3/4
1
1-3/16-12UN
19
22
27
36
41
36
36 (27)
74 (54)
108 (80)
162 (120)
255 (180)
-
29 (22)
49 (36)
78 (58)
118 (87)
137 (100)
177 (130)
10. 33. UPPER SLEWING STRUCTURE
33-66
33.1.20 UPPER FRAME
33.1.20.1 PREPARATION FOR REMOVING
33.1.20.2 REMOVAL
(1) Remove attachment
(See chapter 32)
(2) Remove cab (See 33.1.2 CAB)
(3) Remove guard (See 33.1.4 GUARD)
(4) Remove counterweight
(See 33.1.11 COUNTERWEIGHT)
(5) Remove swivel joint
(See 33.1.19 SWIVEL JOINT)
Temporarily lift upper frame
(1) Lifting up upper frame temporarily
Install two upper swing body lifting jigs and two
bolts M36X120 in the holes into which the
counterweight is placed. Mount two chain blocks to
the boom foot and lift the upper frame at four
points.
Wire rope : ø16(0.630")X2.5m(8ft 2in), 2pcs.
ø16(0.630")X1.5m(4ft 11in), 2pcs.
Chain block : For 1,000kg (2,200 lb) 2pcs.
(2) Marking match marks on swing bearing
Put match marks on upper frame and swing
bearing.
Matching mark on swing bearing and upper frame
(3) Removing upper frame attaching bolts
Remove 33 capscrews (C7) M20X105 and a
reamer bolt (C8) used to install swing bearing and
upper frame.
Tools: Socket: 30mm
(4) Slinging upper frame
Sling according to above Fig, and remove upper
frame and put it on a stand.
Weight: Approx. 5.4ton (11,900 lbs)
Removing upper frame attaching bolts
CHAIN BLOCK
LIFTING JIG
FOR UPPER
FRAME
WIRE ROPE
16 X 2.5m
(0.630") (8ft 2in)
MATCH MARK
11. 33. UPPER SLEWING STRUCTURE
33-67
33
33.1.20.3 INSTALLATION
(1) Installing is done in the reverse order of removing.
(2) Cleaning mating surfaces of upper frame and swing bearing.
(3) Apply Loctite #515 to the inside of the capscrews on the contact surface.
(4) Slinging upper frame
Match marks and install it with a reamer bolt (C8) and a washer (C9) temporarily.
Tools: Socket: 30mm Apply Loctite #262
Tightening torque : 392N-m (290 lbf-ft)
Apply Loctite #262
(5) Install swing bearing
Install 33 capscrews (C7) M20X105.
Tools: Socket: 30 mm Apply Loctite #262
Tightening torque : 392N-m (290 lbf-ft)
Install a reamer bolt (C8).
Tools: Socket: 30mm
Tightening torque : 392N-m (290 lbf-ft)
Confirm the reamer bolt positions referring to above Fig.
Bearing mount
Reamer bolt position (*) Apply Loctite to shaded
area
C8,C9
Apply Loctite #515 to the race surface
over the whole circumference (shaded area)
on the inside of capscrew.
Apply Loctite #262
equivalent.
T=392N-m (290 lbf-ft)
OUTER (S) ZONE POSITION
12. 33. UPPER SLEWING STRUCTURE
33-68
33.2 DISASSEMBLING AND ASSEMBLING
33.2.1 HYDRAULIC PUMP - REGULATOR
33.2.1.1 HYDRAULIC PUMP
33.2.1.1.1 Structural exploded view
(1) Main pump
Structural exploded view of main pump
04
824
127
127
113
806
953
886
535
789
732
W
B X
Z
Y A
534
792
702
532
728
468
271
717
490
251
401 407
325
312
546
901
490
886
C
D
E
F
D
E
727
467
725
466
885
886
710
116
414 05
326
261
774
710
724
111
885
212
214
211
153
156
157
141
717
314
124
727
546
725
B
717
313
124
406
981
983 531.
548
123
151.
152
A
C
F
954
808
15. 33. UPPER SLEWING STRUCTURE
33-71
33
33.2.1.1.2 Disassembly and assembly of main pump
(2) Disassembling procedure
1. Selecting a place for disassembly.
-Choose a clean place.
-Spread rubber sheet or cloth on work
bench to protect parts from damaging.
2. Cleaning
Remove dust and rust,etc.on pump surface with wash oil.
(1) Tools
The right list shows the tools required for remove
and install.
3. Drain oil
Drain out the oil in the pump casing by removing
drain port plug (466), (468).
Tools: Spanner: 19mm, 36mm
-Drain out oil from the plug of the front pump and
the rear pump.
4. Removing regulator and PTO gear casing
Remove the socket bolts [414, 415 (See
Fig."Structural exploded view of main pump",
Fig."Regulator exploded view")]. Then remove the
regulator and the PTO cover (326).
Tools: Allen wrench: 6mm, 8mm
-Regarding the disassembly of the regulator, refer
to article of Regulator.
Tool Part
Name Size mm Size Item No.
Allen wrench
5
6
8
14
17
19
24
30
36
M6
M8
M10
M16
M20
PF1/4
M16
M20
PF3/4
407
406, 412
414
953
401
466
806
808, 954
468
Eye wrench
Socket wrench
Wrench ; Double
single
Crescent wrench
Driver
Hammer
Plier
Steel bar
Torque wrench
Medium size 1pc.
Flat bladed 2pcs.
Plastic
10X8X200
Snap ring
REGULATOR
16. 33. UPPER SLEWING STRUCTURE
33-72
5. Remove gear pump
Remove the socket bolts (435). Then remove the
gear pump (04).
Tools: Allen wrench: 6mm
6. Remove socket bolt (401)
Loosen socket bolts (401) that fasten swash plate
support (251), pump casing (271) and valve block
(312).
Tools: Allen wrench: 17mm
Remove socket bolt (401)
7. Disassembling the pump casing and the valve
block
Place the pump level on a work bench with its
mounting surface of the regulator facing down.
Then separate pump casing (271) and valve block
(312).
-When facing the mounting surface of the regulator
down, place a rubber sheet on a work bench so as
not to score the mounting surface.
-When the pump casing has been separated from
the valve block, draw out the 1st gear (116) at the
same time.
Disassembling the pump casing (271) and the
valve block (312)
8. Drawing out the cylinder assy
Draw out cylinder (141) out of pump casing (271) in
parallel to shaft (111). At the same time draw out
piston (151), plate (153), spherical bushing (156)
and cylinder spring (157).
-Use care so as not to score the sliding surface of
the cylinder, spherical bushing, shoe and the swash
plate.
Drawing out the cylinder assy
9. Remove seal cover (F)
Remove socket bolt (406) M8 and seal cover F
(261).
Tools: Allen wrench: 6mm
-The seal cover (F) may be drawn out with ease if it
is taken out by tightening bolts in the tapped holes
(M6 tap) of the seal cover (F).
-An oil seal is fitted to seal cover (F). Therefore, use
care so as not to score the oil seal.
Removing seal cover F (261)
312
401
271
312 271
271
141(151)(157)
156
153
261
406
17. 33. UPPER SLEWING STRUCTURE
33-73
33
10.Separating the swash plate support and the pump
casing
Knock lightly on the mounting flange of swash plate
support (251) from the pump casing (271) side and
separate the swash plate support from the pump
casing.
Separating the swash plate (251) support and the
pump casing (271)
11.Remove shoe plate and swash plate
Draw out shoe plate (211) and swash plate (212)
from pump casing (271).
Removing shoe (211) and swash plate (212)
12.Drawing out the shaft
Tap lightly the shaft end (111, 113) by means of a
plastic hammer and draw out the shaft from the
swash plate support.
Drawing out the shaft (111), (113)
251
271
271
212(211)
251
111(113)
18. 33. UPPER SLEWING STRUCTURE
33-74
13.Remove valve plate
Remove valve plate (313, 314) from valve block
(312).
-The valve plate may come off during the operation
under 6).
Removing valve plates (313), (314)
14.Remove other parts
If necessary, remove stopper (L) (534), stopper (S)
(535), servo piston (532) and tilting pin (531) from
pump casing (271), and remove needle bearing
(124) from valve block (312).
-When removing the tilting pin, use care so as not
to score the head of the tilting pin, using a jig.
-It is hard to separate the tilting pin from the servo
piston in some cases as Loctite is coated on the
mating part between them. Use care so as not to
score the servo piston by applying undue force.
-Do not draw out needle bearings except when their
service life has ended.
-Do not loosen hex nuts (806),(808) of valve block
(312) and swash plate support (251). A set flow
rate changes.
Removing other parts
314
(313 :
Opposite Side)
312
531
534
535806
532
808
124
312
271
251
19. 33. UPPER SLEWING STRUCTURE
33-75
33
(3) Installing procedure
1. Precautions to be exercised in installation
Assembly is a reverse order of disassembly, but notice the following.
a. Repair scored parts at disassembly. Get replacements ready beforehand.
b. Wash parts sufficiently in cleaning oil and dry them with jet air.
c. Do not forget to coat the sliding areas and bearings with clean hydraulic oil.
d. In principle, replace sealing parts such as O-rings and oil seals.
e. Tighten socket bolts and plugs to specified torques in this manual, using a torque wrench.
f. Do not mix up front pump parts with rear pump parts.
2. Installing swash plate support
Attach swash plate support (251) to pump casing
(271) by tapping the swash plate support lightly
with a plastic hammer.
-When the servo piston, the tilting pin, the stopper
(L) and the stopper (S) have been removed, install
them to the pump casing beforehand.
-When tightening servo piston and tilting pin, use a
jig so as not to damage the head of the tilting pin
and feedback pin.
Coat the screwed part with Loctite #262.
Installing swash plate support (251)
3. Installing swash plate
Place the pump casing with its mounting surface of
the regulator facing down, insert the tilting bushing
of the swash plate into tilting pin (531), and fit
swash plate (212) to swash plate support (251)
properly.
-Confirm by the fingers of your both hands that
swash plate moves smoothly.
-The shaft be installed easily if grease is applied to
the sliding parts of swash plate and swash plate
support.
-Do not damage the sliding surface of shoe plate.
Installing swash plate (212)
251
271
251
212
271(531)
20. 33. UPPER SLEWING STRUCTURE
33-76
4. Installing shaft
Install shaft (111) fitted with bearing (123), bearing
spacer (127) and snap ring (824), to swash plate
support (251).
-Do not knock on the shaft with a hammer or
something.
-Fix the bearing by lightly tapping the outer race of
it by means of a plastic hammer and set it exactly to
the end by using a steel rod and others.
Installing shaft (111)
5. Installing seal cover
Assemble seal cover (F) (261) to pump casing
(271) and fix it with socket bolts (406).
Tools: Allen wrench: 6mm
Tightening torque: 29N-m (22 lbf-ft)
-Coat the oil seal in seal cover (F) with a thin film of
grease.
-Handle the oil seal with sufficient care so it is not
scored.
Installing seal cover F (261)
6. Inserting piston cylinder sub
Assemble the piston cylinder sub [cylinder block
(141), piston (151), shoe (152), plate (153),
spherical bushing (156) and cylinder spring (157)].
Align the spherical bushing with the cylinder spline
and insert them into the pump casing.
Inserting piston cylinder sub
7. Installing valve plate
Install valve plate (313), (314) to valve block (312)
by aligning pin.
-Do not mistake the suction and delivery sides of
the valve plate.
Installing valve plates (313), (314)
251
123
127,824
111
406
261
271
153
156
141(151,152,157)
312
314
(313 :
Opposite Side)
21. Thank you very much for
your reading. Please Click
Here. Then Get COMPLETE
MANUAL. NO WAITING
NOTE:
If there is no response to
click on the link above,
please download the PDF
document first and then
click on it.
22. 33. UPPER SLEWING STRUCTURE
33-77
33
11.Installing drain port plug
The work is complete when drain port VP plugs (466), (468) have been set.
Tools: Allen wrench: 19mm, 36mm
Tightening torque; 36N-m (27 lbf-ft), 170N-m (125 lbf-ft)
8. Installing valve block
Install valve block (312) to pump casing (271) and
fasten them together with socket bolts (401).
Tools: Allen wrench: 17mm
Tightening torque ; 430N-m (320 lbf-ft)
-Work will be promoted if assembly is started from
the rear pump.
-Exercise care so as not to mistake the direction of
the valve block (312). (Install it so the regulator
comes up as seen from the front side and the
suction flange comes on the right.)
-Insert the 1st gear into the valve block beforehand
and connect it with the spline of the shaft.
Installing valve block (312)
9. Installing gear pump
Install gear pump (04) and fasten them together
with socket bolts (435).
Tools: Allen wrench: 6mm,
Tightening torque; 17N-m (12.5 lbf-ft)
10.Installing regulator and PTO cover
Pinch feedback pin of tilting pin in feedback lever of
the regulator and PTO cover (326), install the
regulator and fasten socket bolt.
(415) (See Fig."Regulator exploded view")
Socket bolt (415): For regulator
Tools: Allen wrench: 6mm,
Tightening torque; 29N-m (21 lbf-ft)
Socket bolt (414): PTO Cover (326)
Tools: Allen wrench: 8mm,
Tightening torque; 57N-m (42 lbf-ft)
-Do not mistake the front regulator for the rear
regulator.
Installing regulator and PTO cover
312
401
271
REGULATOR
23. 33. UPPER SLEWING STRUCTURE
33-78
33.2.1.1.3 Maintenance standards
(1) Replacement standards for abrasive parts
Replace or readjust parts that exceed the following standards of wear.
However, always replace such parts that show excessive damage on appearance.
(2) Repair standards for cylinder, valve plate and swash plate (shoe plate face)
Part name and inspection item
Standard
dimension
Recommende
dvalue
forreplacement
Remedy
Clearance between piston and cylinder bore (D-d)
0.039
(0.0015 )
0.067
(0.0026 )
Replace piston or cylinder.
Gap between piston and caulked part of
shoe
0 - 0.1
(0.004 )
0.3
(0.012 )
Replace piston shoe assy.
Thickness of shoe (t)
4.9
(0.193 )
4.7
(0.185 )
Replace piston shoe assy.
Free height of cylinder spring (L)
41.1
(1.618 )
40.3
(1.587 )
Replace cylinder spring.
Combined height of retainer plate and
spherical bushing
(H-h)
23.0
(0.906 )
22.0
(0.866 )
Replace spherical bushing or
retainer plate.
Valve plate (sliding section)
Swash plate (shoe plate face)
Cylinder (sliding section)
Roughness of each surface
Surface roughness requiring correction 3 - Z
Standard surface roughness
(correction value)
Less than 0.4Z (lapping)
( )
Clearance between piston and
cylinder bore : D-d
h
H
D
d
Combination of retainer plate and spherical
bushing Height=H-h
Gap between piston and shoe :
thickness of shoe : t Free height cylinder spring : L
t
L
24. 33. UPPER SLEWING STRUCTURE
33-79
33
33.2.1.1.4 Troubleshooting
(1) Locating causes of troubles
The pump is usually fitted with a regulator, auxiliary valves and auxiliary pumps, and this makes fault location
extremely difficult. However, faults would be found out easily if the following check items were attended to.
1. Inspecting the filter and drain oil
Inspect the filter element to check for abnormal contaminations. Some metallic particles will be deposited on it
as the shoe and the cylinder wear off. In case metallic particles are found in large quantity, the elements may be
damaged. In that case check the drain oil in the pump casing as well.
2. Checking for abnormal vibration and sound
Check that the pump does not vibrate and make an abnormal sound.
Check that the hunting of the regulator and the attached valveAfs relief valve are of regular frequency. In case
vibration and sound are abnormal, the pump may be making a cavitation or internally broken.
3. When two pumps are used
In case two single pumps or motors are used or when a double pump is used. change pump pipelines. This will
make clear that the pumps are faulty or the circuit after the pumps is faulty.
4. Pressure measurements
If the problem is related to control functions, avoid disassembling the pumps carelessly, but look for causes by
measuring pressures.
(2) Troubleshooting
1. Overloading to engine
2. Pump's oil flow rate is extremely low and delivery pressure is not available.
Cause Remedy Remarks
1.
Revolution and pressure are higher
than set values.
1)
Set pressure to specified value.
2.
Regulator torque is set higher than
normal.
2)
Readjust regulator.
2)
Refer to Regulator Manual.
3.
PumpAfs internal parts are seized or
broken.
3)
Replace damaged parts.
3)
Check filter and drain oil to see if
abnormal wear particles are present.
4.
Regulator is piped incorrectly.
4)
Pipe regulator correctly.
Cause Remedy Remarks
1.
Regulator is out of order
1)
Repair regulator.
1)
Refer to Regulator Manual.
2.
Pump's internal parts are seized or
broken.
2)
Replace damaged parts.
2)
Check filter and drain oil.
3.
Attached pump is out of order
3)
Replace damaged parts.
3)
Remove attached pump and check
shaft joint.
4.
Attached valve is out of order.
4)
Check attached valve. Particularly
poppet, seat and spring.
4)
Refer to Manual for Attached Valve.
5.
Regulator is piped incorrectly.
5)
Pipe correctly.
