Jcb 155 hd skid steer loader service repair manual (sn 2431601 and up)

SERVICE MANUAL
SKIDSTEER LOADER
135 HD, 155 HD
EN - 9813/4450
ISSUE 2 - 03/2017
This manual contains original instructions, verified by
the manufacturer (or their authorized representative).
Copyright 7-03-08 © JCB SERVICE
All rights reserved. No part of this publication may
be reproduced, stored in a retrieval system, or
transmitted in any form or by any other means,
electronic, mechanical, photocopying or otherwise,
without prior permission from JCB SERVICE.
www.jcb.com
Foreword
The Operator's Manual
You and others can be killed or seriously injured
if you operate or maintain the machine without
first studying the Operator's Manual. You must
understand and follow the instructions in the
Operator's Manual. If you do not understand
anything, ask your employer or JCB dealer to
explain it.
Do not operate the machine without an Operator's
Manual, or if there is anything on the machine you
do not understand.
Treat the Operator's Manual as part of the machine.
Keep it clean and in good condition. Replace the
Operator's Manual immediately if it is lost, damaged
or becomes unreadable.
Contents
01 - Machine
03 - Attachments, Couplings and Load
Handling
06 - Body and Framework
09 - Operator Station
12 - Heating, Ventilating and Air-
Conditioning (HVAC)
15 - Engine
18 - Fuel and Exhaust System
21 - Cooling System
24 - Brake System
27 - Driveline
30 - Hydraulic System
33 - Electrical System
72 - Fasteners and Fixings
75 - Consumable Products
78 - After Sales

18 - Injection
21 - Governor
18 - 34 9813/4450-2 18 - 34
Component Identification
Figure 268. Governor control mecha-
nism in the front housing without a BCD
A
C
E
F
D
B
A Connection for the linkage to the fuel injection
pump
B Control lever
C Lever return spring
D Governor adjustment screw
E Arm
F Start spring
nism in the front housing with a BCD
G
H
J
A
B
pump
B Control lever
G Governor main spring
H Adjuster (Angleich unit)
J Governor lever
Operation
The fuel rack is connected to the linkage, which
controls the fuel injection pump. This linkage is
located in the front case.
The engine has a mechanical governor to control the
engine speed. The governor operates for all engine
RPM (Revolutions Per Minute). The governor weight
assembly is installed on the front of the camshaft
gear. The other components of the governor are
installed in the front case.
nism in the front housing without a BCD
A
C
E
F
D
B
pump
B Control lever
C Lever return spring
D Governor adjustment screw
E Arm
F Start spring

18 - Injection
21 - Governor
18 - 35 9813/4450-2 18 - 35
nism in the front housing with a BCD
G
H
J
A
B
pump
B Control lever
G Governor main spring
H Adjuster (Angleich unit)
J Governor lever
The movement of the governor weight assembly
is transferred to the fuel rack on the fuel injection
pump by the control lever, the governor lever and
the linkage to the fuel injection pump. The governor
main spring connects the governor lever to the
control lever. The governor main spring controls
the movement of the governor weight assembly on
the camshaft. When the angle of the control lever
changes, the tension on the governor main spring
changes. This action controls the linkage to the fuel
rack on the fuel injection pump, which controls the
engine RPM.
The maximum fuel adjustment screw is mounted in
the front case. This adjustment regulates the fuel
injection at high engine RPM. This adjustment should
only be made by personnel with the correct training.
The fuel injection pump timing, the low idle and the
high idle are preset at the factory. Adjustments to
the pump timing and idle RPM should only be made
by personnel that have had the correct training. The
timing for the fuel injection pump should only change
if the camshaft or the crankcase are replaced. The
fuel injection pump timing should not change if the
fuel injection pump is reinstalled with a shim that is
the same size.
The fuel rack automatically returns to the excess fuel
position when the engine is stopped. The excess
fuel position helps the engine to starting in cold
conditions.
A spring connects the linkage to the fuel injection
pump and the mechanical stop control. When the
engine is first started, the spring automatically
increases the fuel flow to the cylinders.

18 - Injection
21 - Governor
18 - 36 9813/4450-2 18 - 36
Adjust
Special Tools
Description Part No. Qty.
Digital Tachometer 892/00284 1
The setting of the front case is only necessary if the
front case is damaged or if the front case is renewed.
Record the Governor Settings
1. If the front case is removed, install the front case.
Refer to (PIL 15-51).
2. Record the setting of the low idle stop screw and
the high idle stop screw. This is to make sure the
governor operation is restored.
3. Operate the engine until the normal operating
temperature is reached.
4. Record the engine RPM (Revolutions Per
Minute) at low idle with an optical tachometer.
Special Tool: Digital Tachometer (Qty.: 1)
5. Accelerate the engine to high idle. Record
the engine RPM as Speed A with an optical
tachometer.
Figure 272.
A
B
C
A Tamperproof caps
B Protrusion of the high idle stop screw
C Protrusion of the low idle stop screw
Figure 273.
D
E
F
G
D Idle trimmer screw
E Locknut
F High idle stop screw
G Low idle stop screw
6. Remove the tamperproof caps.
7. Record the protrusion of the high idle stop screw.
8. Record the protrusion of the low idle stop screw.
9. Release the locknut. Turn the high idle trimmer
screw four turns counterclockwise and tighten
the locknut.
10. Accelerate the engine to high idle. Record
the engine RPM as Speed B with an optical
tachometer.
11. Make sure that the recorded Speed B is lower
than the recorded Speed A.
Removal of the Old Front Case
1. Remove the fuel injection pump. Refer to (PIL
18-18).
2. Remove the crankshaft pulley. Refer to (PIL
15-12).
3. Remove the front case. Refer to (PIL 15-51).

18 - Injection
21 - Governor
18 - 37 9813/4450-2 18 - 37
Figure 274.
U
V
U Front case
V Gasket
4. Remove the gasket. Make sure that the face of
the front plate is clean.
5. Install the Allen head screw to the lever
assembly. Tighten the Allen head screw to the
correct torque value.
Figure 275.
H
J
H Allen head screw (M4 x 20mm x 0.70)
J Lever assembly
6. Remove the start spring and replace the start
spring with a calibration spring.
Figure 276.
K
L
K Calibration spring
L Start spring
7. Install the front case. Refer to (PIL 15-51).
7.1. Do not install a gasket. Refer to Figure 274.
8. Install the fuel injection pump. Refer to (PIL
18-18).
8.1. Install the original shim.
9. Install the crankcase adaptor into the crankcase.
10. Install the DTI (Dial Test Indicator) holder into the
crankcase adaptor.
10.1. The DTI must be graduated to the
specified dimension.
Dimension: 0.01mm
11. Assemble the DTI and the extension to the
Dimension: 20mm
Figure 277.
Q
M
N
P
M DTI
N DTI holder
P Crankcase adaptor
Q Crankcase

18 - Injection
21 - Governor
18 - 38 9813/4450-2 18 - 38
12. Install the DTI into the DTI holder until the
extension on the DTI touches the rack of the fuel
injection pump.
13. Push the assembled DTI and the extension into
the DTI holder further to the specified distance.
Dimension: 2mm
Figure 278.
R
M
P
N
M DTI
N DTI holder
P Crankcase adaptor
R Crankcase
14. Lock the DTI holder to retain the DTI in position.
Set the DTI to the specified dimension.
Dimension: 2 ± 0.01mm
15. Push the plunger of the DTI several times to seat
the rack of the fuel injection pump. When the
plunger is gently released, check that the DTI
reads the specified dimension.
16. If the rack of the fuel injection pump has heavy
resistance to movement:
16.1. Remove the DTI.
16.2. Remove the fuel injection pump.
16.3. Wash the fuel injection pump with a
suitable cleaner.
16.4. Install the fuel injection pump.
16.5. Repeat the steps 12 to 15.
17. Do the calibration of the fuel screw and the front
housing. Refer to (PIL 18-18).
Final Installation of the New Front Case
1. Remove the DTI and the DTI holder. Refer to
Figure 277.
2. Remove the crankcase adaptor. Refer to Figure
277.
3. Remove the fuel injection pump. Refer to (PIL
18-18).
4. Remove the front case. Refer to (PIL 15-51).
5. Remove the calibration spring and install the
original start spring. Refer to Figure 276.
6. Remove the Allen head screw from the lever
assembly. Refer to Figure 275.
7. Install the new gasket on the front case. Make
sure that the gasket is clean and free from
damage. Refer to Figure 274.
8. Install the new front case. Refer to (PIL 15-51).
9. Set the protrusion of the high idle stop screw to
the same dimensions as the stop screws on the
original front case. Refer to Figure 272.
10. Set the protrusion of the low idle stop screw to
the same dimensions as the stop screws on the
original front case. Refer to Figure 272.
11. Set the high idle trimmer screw as follows: Refer
to Figure 273.
11.1. Release the locknut.
11.2. Set the high idle trimmer screw to the fully
out position.
11.3. Turn the screw clockwise for two turns.
11.4. Tighten the locknut.
12. Install the fuel injection pump. Refer to (PIL
18-18).
13. Start the engine and allow the engine to reach
the normal operating temperature.
14. Run the engine at low idle and adjust the low
idle stop screw to the speed that was previously
recorded, prior to the original front case removal.
15. Run the engine at high idle and adjust the high
idle stop screw to the speed that was previously
recorded as Speed B.
16. Run the engine at high idle and release the
locknut.
17. Adjust the high idle trimmer screw to the speed
that was previously recorded as Speed A.
18. Tighten the locknut.
18.1. Make sure that the recorded Speed B is
lower than the recorded Speed A.
19. Make sure that the engine operates correctly.

18 - Injection
21 - Governor
18 - 39 9813/4450-2 18 - 39
20. Install the tamperproof cap to the high idle
trimmer screw and the high idle screw.
21. Carefully install the tamperproof cap to the fuel
screw.
Figure 279.
W
W Fuel screw
Table 98. Torque Values
Item Description Nm
H Allen head screw .4
Calibrate
Setting the Fuel Screw
1. Release the plunger of the DTI (Dial Test
Indicator). Refer to Figure 280.
Figure 280.
R
M
P
N
M DTI
N DTI holder
P Crankcase adaptor
R Crankcase
2. Do not move the position of the DTI, DTI holder
and crankcase adaptor.
3. Retain the locknut of the fuel screw in position
with a ring spanner. Refer to Figure 281.
Figure 281.
T
S
S Allen wrench
T Ring Spanner
4. Turn the Allen head screw and observe the
reading on the DTI.

18 - Injection
21 - Governor
18 - 40 9813/4450-2 18 - 40
5. Turn the Allen head screw until the DTI reads the
6. Tighten the locknut to the correct specified torque
value.
Torque: 6N·m
7. Make sure that the reading on the DTI is as
specified.
8. Install and adjust the new front case. Refer to
(PIL 15-51).

18 - Injection
24 - Adjuster
18 - 42 9813/4450-2 18 - 42
Remove and Install
Consumables
Description Part No. Size
4101/0250 0.01L
JCB Threadlocker
and Sealer (Medium
Strength)
4101/0251 0.05L
Remove
1. Disassemble the timing gear front case. Refer to
(PIL 15-51).
2. Remove the lever assembly from the front case.
3. Remove the adjuster unit from the lever
assembly. Refer to Figure 282.
Figure 282.
G
K
G Lever assembly
K Adjuster unit
Install
1. Apply threadlocker on the first two threads of the
adjuster unit.
Consumable: JCB Threadlocker and Sealer
(Medium Strength)
2. Install the adjuster unit to the lever assembly.
3. Tighten the adjuster unit to the correct torque
value.
4. Make sure that the threadlocker does not
contaminate the plunger assembly of the
adjuster unit. The contamination of the plunger
assembly will make the adjuster unit inoperative.
5. Install the lever assembly to the front case.
6. Assemble the timing gear front case. Refer to
(PIL 15-51).

21 - Fuel Pump
00 - General
18 - 47 9813/4450-2 18 - 47
Remove and Install
Observe all the health and safety information. Refer
to Fuel system - Health and Safety (PIL 18-00).
Electrical Fuel Pump
Remove
1. Make the machine safe. Refer to (PIL 01-03).
2. Open the rear access cover. Refer to (PIL 06-06).
3. Turn the fuel supply to the OFF position.
4. Disconnect the electrical connector from the fuel
pump.
5. Plug all the open ports and hoses to prevent
contamination.
6. Loosen the clamps and disconnect the hoses.
7. Put a label on the hoses to help installation.
8. Remove the bolt1 (x2) and remove the fuel pump.
Figure 284.
E
D
B
C
D
E
A
A Electrical connectors
B Bolt1 (x2)
C Fuel pump (Electrical)
D Clamps
E Hoses
Install
1. The installation procedure is the opposite of the
removal procedure. Additionally do the following
steps.
2. Make sure that the electric transfer pump is clean
and free from damage.
3. Bleed the fuel system. Refer to Fuel system (PIL
18-00).
Mechanical pump
Remove
2. Open the rear access cover. Refer to (PIL 06-06).
3. Turn the fuel supply to the OFF position.
4. Disconnect the electrical connector from the fuel
pump.
5. Plug all the open ports and hoses to prevent
contamination.
6. The fuel transfer pump can be oriented in two
positions. Before you remove the fuel pump from
the crankcase, note the orientation of flange on
the fuel pump for installation.
7. Loosen the clamps and disconnect the hoses.
8. Put a label on the hoses to help installation.
9. Loosen the bolt and remove the fuel pump from
the crankcase.
9.1. If necessary, rotate the crankshaft until the
operating plunger of the fuel pump is not
under pressure to remove the fuel pump.
10. Remove the O-ring seal from the fuel pump.
Figure 285.
F G
H
J
K
F Fuel pump (Mechanical)
G Bolt2
H O-ring seal
J Bolt3
K Flange
Install
1. Clean the mating surfaces of the crankcase and
the flange on the fuel pump.
2. Make sure that the camshaft lobe for the fuel
pump is at the minimum lift before the fuel pump
is installed.
3. Make sure that the fuel pump is oriented in the
correct position.
4. Install the new O-ring seal to the fuel pump.

21 - Fuel Pump
00 - General
18 - 48 9813/4450-2 18 - 48
5. Lubricate the operating plunger of the fuel pump
with clean engine oil.
6. Position the fuel pump on the crankcase.
7. Make sure that the operating plunger is
positioned correctly on the camshaft lobe.
8. Install the bolt3.
9. Tighten the bolt3 to the correct torque value.
10. Connect the hoses to the fuel pump.
11. Tighten the hose clamps.
12. The inlet for the fuel pump can be rotated to the
specified angle by loosening bolt2.
Angle: 360°
12.1. The fuel inlet is adjustable to the specified
degree increments.
Angle: 15°
12.2. If adjustment is made to the position of the
fuel inlet, tighten bolt2 to the correct torque
value.
13. Turn the fuel supply to the ON position.
14. Bleed the fuel system. Refer to Fuel system (PIL
18-00).
Item Description Nm
B Bolt1 9
G Bolt2 2.5
J Bolt3 6

35 - Turbocharger
00 - General
18 - 63 9813/4450-2 18 - 63
00 - General
Introduction .................................................... 18-63
Component Identification ............................... 18-64
Operation ....................................................... 18-65
Check (Condition) .......................................... 18-65
Check (Operation) ......................................... 18-66
Remove and Install ....................................... 18-67
Store and Recommission .............................. 18-69
Introduction
A turbocharger increases the temperature and the
density of the air sent to the engine cylinder. This
condition causes a lower temperature of ignition
to develop earlier in the compression stroke. The
compression stroke is also timed in a more accurate
way with the fuel injection. The surplus air lowers
the temperature of combustion. This surplus air also
provides internal cooling.
A turbocharger improves the following aspects of
engine performance:
• Power output is increased.
• Engine torque is increased.
• Engine efficiency is increased.
Figure 289.
A
K
L
D
E
F
G
H
J
B
C
A Air intake
B Compressor housing
C Compressor wheel
D Bearing
E Oil inlet port
F Bearing
G Turbine housing
H Turbine wheel
J Exhaust outlet
K Oil outlet port
L Exhaust inlet

35 - Turbocharger
00 - General
18 - 64 9813/4450-2 18 - 64
Component Identification
Figure 290.
A
B
J
K
L
M
B
G
H
E
W
E
V
T
D
F
C
U
Q
N
S
P
R
A Air inlet hose B Hose clamp
C Screw D Exhaust elbow
E Turbocharger F Gasket 1
G Banjo bolt H Washer
J Tube clips K Bolt1
L Tube assembly 1 M O-ring
N Bolt 2 P Tube assembly 2
Q Joint 1 R Joint 2
S Bolt 3 T Nut
U Gasket 2 V Stud
W Tube connector

35 - Turbocharger
00 - General
18 - 65 9813/4450-2 18 - 65
Operation
The turbocharger is installed between the exhaust
manifold and the intake manifold. The turbocharger
is driven by exhaust gases which flow through the
exhaust inlet. The energy of the exhaust gas turns
the turbine wheel. Then, the exhaust gas flows out of
the turbine housing through the exhaust outlet.
The turbine wheel and the compressor wheel are
installed on the same shaft. Therefore, the turbine
wheel and the compressor wheel rotate at the same
RPM (Revolutions Per Minute). The compressor
wheel is enclosed by the compressor housing. The
compressor wheel compresses the intake air. The
intake air flows into the engine cylinders through the
inlet valves of the cylinders.
The oil from the main gallery of the crankcase
flows through the oil inlet port to lubricate the
turbocharger bearings (Bearing1 and bearing2). The
pressurised oil passes through the bearing housing
of the turbocharger. The oil is returned through the
oil outlet port to the oil pan.
The turbocharger has a wastegate. The wastegate is
controlled by the boost pressure. This allows some
of the exhaust gases to bypass the turbine wheel
at higher engine speeds. The wastegate is a type
of flapper valve that automatically opens at a preset
level of boost pressure in order to allow the exhaust
gas to flow around the turbine. The wastegate allows
the design of the turbocharger to be more effective
at lower engine speeds.
Check (Condition)
1. Inspect the compressor and turbine for damage.
2. Make sure that the compressor blades do not rub
on the housing and rotate freely. It is normal to
detect a bit of play on the blades.
3. Make sure that the shaft rotates freely.
4. Before you install the turbocharger, make sure
that the code of the component is correct for
the type of engine, as installation of the wrong
turbocharger can damage the turbo and engine
and void the warranty.

35 - Turbocharger
00 - General
18 - 66 9813/4450-2 18 - 66
Check (Operation)
To maximise the duration of the turbocharger follow
the rules described below.
Start-up
Start the engine and keep it at idle speed for about a
minute. The oil operating pressure is reached within
a few seconds, but it is useful to allow the moving
parts to warm up in good lubrication conditions.
Immediately increasing the engine speed after start
up will result in the turbocharger running at high rpm
with less than optimal lubrication. This may lead to
premature failure of the turbocharger.
After maintenance
When carrying out maintenance on the engine
or turbocharger, pre-lubricate the oil inlet of the
turbocharger by adding clean lubricant until it is
completely full. After pre-lubrication, let the engine
run via the starter motor without firing (engine /
fuel pump stop out) to allow the oil to circulate
through the complete system under pressure. Upon
engine start-up, make it run at idle speed for a few
minutes, allowing the oil and bearings system to work
satisfactorily.
Low temperature air or engine inactivity
If the engine has been inactive for a certain period
of time or the air temperature is very low, start
the engine and then let it run at idle speed. This
enables the oil to go into the lubrication system
before applying high loads and speeds to the engine
and turbocharger.
Engine shutdown
Before switching the engine off after intense activity,
you must allow the turbocharger to cool down, let the
engine run at idle speed for at least 2 minutes to allow
the turbocharger to cool.
Engine at idle speed
Avoid running the engine at idle speed for long
periods (above 20-30 minutes). Idle operation leads
to low pressure values in the turbocharger, which
may cause oil leaks from the seals at the ends of
the turbo bearing shaft. Even if this does not cause
damage, it can cause blue smoke from the exhaust
when the engine speed and load are increased.

35 - Turbocharger
00 - General
18 - 67 9813/4450-2 18 - 67
Remove and Install
Remove
1. Make sure you obey the special instructions
on handling, operation and installation of the
turbocharger. Refer to (PIL 18-35).
3. Make sure that the engine is safe to work on. If
the engine has been running, let it cool before
you start the service work.
4. Loosen the hose clamp and remove the air inlet
hose.
5. Remove the screw and remove the exhaust
elbow.
6. Remove the gasket 1.
7. Remove the banjo bolt and the washer.
8. Remove the fasteners and spacers from the tube
clips.
9. Remove the bolt 1 and remove the tube
assembly 1 from the crankcase.
10. Remove and discard the O-ring.
11. Remove the bolt 2 and disconnect the tube
assembly 2 from the turbocharger.
12. Remove and discard the joint 1.
13. If necessary, remove the bolt 3 and remove the
tube assembly 2 from the crankcase.
14. Remove and discard the joint 2.
15. Remove the nut and the turbocharger from the
exhaust manifold.
16. Remove and discard the gasket 2 from the
exhaust manifold.
17. If necessary, remove the stud from the exhaust
manifold.
Important: Do not use the actuator rod of the
wastegate to lift the turbocharger.
Figure 291.
A
B
J
K
L
M
B
G
H
E
W
E
V
T
D
F
C
U
Q
N
S
P
R
A Air inlet hose B Hose clamp
C Screw D Exhaust elbow
E Turbocharger F Gasket 1
G Banjo bolt H Washer
J Tube clips K Bolt1
L Tube assembly 1 M O-ring
N Bolt2 P Tube assembly 2
Q Joint 1 R Joint 2
S Bolt 3 T Nut
U Gasket 2 V Stud
W Tube connector

35 - Turbocharger
00 - General
18 - 68 9813/4450-2 18 - 68
Install
1. Make sure that all the parts are clean and free
from contamination.
2. Check the turbocharger for wear or damage. If
the turbocharger is worn, replace the complete
turbocharger.
3. Check the actuator for correct operation. Refer to
(PIL 18-35).
4. If the actuator is damaged or does not operate
within the specified limits, replace the complete
turbocharger.
5. Clean the mating surfaces of the exhaust
manifold.
6. If removed, install the studs to the exhaust
manifold.
7. Tighten the studs to the correct torque value.
8. Install the new gasket 2 on the studs.
9. Keep the turbocharger on the exhaust manifold
at its correct position.
10. Install the nuts and tighten to the correct torque
value.
11. Make sure that the tube assembly 1 and tube
assembly 2 are clean and free from damage. If
necessary, replace the tube assemblies.
12. If removed, keep the new joint 2 at its correct
position on the crankcase with the tube assembly
2.
13. Install the bolt 3 and tighten to the correct torque
value.
14. Keep the new joint 1 at its correct position on the
tube assembly 2. Align the tube assembly 2 with
the bottom of the turbocharger.
value.
16. Lubricate the bearings of the turbocharger with
the clean engine oil through the oil inlet port.
17. Rotate the shaft of the turbocharger to distribute
the oil.
18. Install the new O-ring on the tube assembly 1.
19. Keep the tube assembly 1 at its correct position
on the crankcase.
value.
21. Install the new washer and banjo bolt to the tube
assembly 1.
22. Keep the tube assembly 1 at its correct position
on the turbocharger.
23. Install the tube clips with the fasteners and
spacers.
24. Tighten the banjo bolt to the correct torque value.
25. Make sure that the tube assemblies do not touch
any other components.
26. Clean the mating surfaces of the exhaust elbow.
27. Keep the new gasket 1 and exhaust elbow at its
correct position on the turbocharger.
28. Install the screw and tighten to the correct torque
value.
29. Make sure that the inlet hoses are clean and free
from the defects or restrictions.
30. Loosely install the hose clamps on the air inlet
hose.
31. Install the inlet hose and then tighten the hose
clamps.
Item Description Nm
C Screw 32
G Banjo bolt 18
K Bolt 1 10
N Bolt 2 10
S Bolt 3 10
T Nut 25
V Stud 18

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35 - Turbocharger
00 - General
18 - 69 9813/4450-2 18 - 69
Store and Recommission
What to do
• Before assembling the turbocharger, make sure
that the protection caps are installed on all
openings of the turbocharger.
• Make sure that the packaging is correct before
storing the turbocharger to be assembled.
• Make sure the turbocharger is pre-lubricated.
• Periodically check that the joints are sealed
against oil and air.
• Use only the specified lubricating oil.
• Check the engine oil level.
• Before switching the engine off after use, let it
run at idle speed for around 1 minute.
• Check the condition of the air and oil filter
regularly as per the maintenance schedules.
• Make sure that the engine maintenance
intervals are observed.
• Make sure that the engine and equipment are
used in a way that is not harmful to the life of
the turbocharger.
What not to do
• Do not store the turbochargers in stacks.
• Do not store the turbochargers in damp or wet
conditions.
• Do not expose the turbochargers to dust and
dirt.
• Do not lift the turbocharger by holding the
actuator rod.
• Do not increase the engine speed immediately
after start-up.
• Do not run the engine at idle speed for more
than 20-30 minutes at a time.
• Do not change the actuator settings.
Practical operating rules
1. Start-up: Start the engine and keep it at idle
speed for about a minute. The oil operating
pressure is reached within a few seconds, but
it is useful to allow the moving parts to warm
up in good lubrication conditions. Immediately
increasing the engine speed after start up will
result in the turbocharger running at high RPM
(Revolutions Per Minute) with less than optimal
lubrication. This may lead to premature failure of
the turbocharger.
2. After maintenance: When carrying out
maintenance on the engine or on the
turbocharger, pre-lubricate the oil inlet of the
turbocharger by adding clean lubricant until it
is completely full. After pre-lubrication, let the
engine run via the starter motor without firing,
to allow the oil to circulate through the complete
system under pressure. Upon engine start-up,
make it run at idle speed for a few minutes,
allowing the oil and bearings system to work
satisfactorily.
3. Low temperature air or engine inactivity: If the
engine has been inactive for a certain period of
time or the air temperature is very low, start the
engine and then let it run at idle speed. This
enables the oil to go into the lubrication system
before applying high loads and speeds to the
engine and turbocharger.
4. Engine shutdown: Before switching off the
engine after intense use allow the turbocharger
to cool down. Therefore run the engine at idle
speed for at least 2 minutes that allow the
turbocharger to cool down.
5. Engine at idle speed: Do not run the engine at
idle speed for more than 20-30 minutes at a time.
It may cause oil leaks from the seals at the end of
the engine shaft or it can cause blue smoke from
the exhaust when the engine speed and load are
increasing.

35 - Turbocharger
06 - Wastegate Valve
18 - 71 9813/4450-2 18 - 71
Operation
The wastegate controls the amount of exhaust gas
that is allowed to bypass the turbine side of the
turbocharger. This valve then controls the RPM
(Revolutions Per Minute) of the turbocharger.
When the engine operates in conditions of low boost,
a spring presses against a diaphragm in the canister.
The actuating rod will move and the wastegate
will close. Then, the turbocharger can operate at
maximum performance.
When the boost pressure increases against the
diaphragm in the canister, the wastegate will open.
The RPM of the turbocharger becomes limited. The
RPM is limited because a portion of the exhaust
gases bypass the turbine wheel of the turbocharger.
Check (Condition)
WARNING Hot oil and engine components can
burn you. Make sure the engine is cool before
doing this job.
Used engine crankcase lubricants contain
harmful contaminants. In laboratory tests it was
shown that used engine oils can cause skin
cancer.
Important: The turbocharger is a non-serviceable
item. The pressure for the wastegate can be checked
but not adjusted. For a pressure check of the
wastegate, refer to (PIL 18-35).
Before you check the condition of the wastegate,
make sure that the inlet air and exhaust system
restrictions are within the specified limits.
1. The following levels of boost pressure indicate a
problem with the wastegate:
1.1. Too high in full load conditions.
1.2. Too low in all low boost conditions.
2. The boost pressure controls the maximum RPM
(Revolutions Per Minute) of the turbocharger,
because the boost pressure controls the position
of the wastegate. The following factors also affect
the maximum RPM of the turbocharger:
2.1. The engine rating.
2.2. The horsepower demand on the engine.
2.3. The high idle RPM
2.4. Inlet air restriction.
2.5. Exhaust system restriction.

35 - Turbocharger
06 - Wastegate Valve
18 - 72 9813/4450-2 18 - 72
Check (Pressure)
1. Make sure you obey the special instructions
on handling, operation and installation of the
turbocharger. Refer to (PIL 18-35).
3. Make sure that the engine is safe to work on. If
the engine has been running, let it cool before
you start the service work.
4. Get access to the turbocharger. Refer to (PIL
06-06).
5. Remove the heatshield from the turbocharger.
6. Remove the guard for the wastegate.
7. Remove the boost line from the wastegate.
8. Connect an air supply to the wastegate that can
be adjusted accurately.
9. Install a DTI (Dial Test Indicator) to the
turbocharger so that the end of the actuator rod
is in contact with the plunger of the DTI. This will
measure the axial movement of the actuator rod.
10. Slowly apply air pressure to the wastegate so that
the actuator rod moves to the specified distance.
Distance: 1mm
10.1. Make sure that the air pressure applied is
within the specified limit.
Pressure: 0.52bar (7.5psi)
11. Make sure that the DTI returns to zero when the
air pressure is released.
12. Repeat the test several times to make sure that
you get an accurate reading.
13. If the wastegate does not operate correctly,
contact your JCB dealer.

Jcb 155 hd skid steer loader service repair manual (sn 2431601 and up)

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Jcb 155 hd skid steer loader service repair manual (sn 2431601 and up)