Volvo Engine Brake VE D12, D12A, D12B. Manual - part 9

Group 25

Troubleshooting

T2007703

Check if the exhaust pressure gover-
nor shutter seals against the shutter
housing.

6
If the shutter does not seal against the
housing, replace or overhaul the ex-
haust pressure governor according to
the procedures found in:

Service
Manual

V776–250–600SM
Intake and Exhaust
Systems, VE D12

7
If the shutter seals against the hous-
ing, remove the exhaust pressure
governor and check the shutter and
shutter housing.

2533-06-02-02
Oil Pressure, Compression
Brake, Checking

Before working on a vehicle, set the parking brakes,
place the transmission in neutral, and block the
wheels. Failure to do so can result in unexpected ve-
hicle movement and can cause serious personal
injury or death.

Never disconnect an air system component unless all
system pressure has been depleted. Failure to de-
plete system pressure before disconnecting hoses or
components may result in their violent separation and
can cause serious bodily injury.

WARNING

HOT ENGINE! Keep yourself and your test equipment
clear of all moving or hot engine parts. A hot engine
can cause serious burns or can permanently damage
test equipment.

WARNING

Always wear appropriate eye protection to prevent the
risk of eye injury due to contact with engine debris or
fluids.

Group 25

Troubleshooting

(Measured at rocker shaft.)

Special tools: 9998338, 9998339, J–41203
(Kent Moore)

Installation

1
Set the parking brake.

T2006731

Remove the valve cover.

Note: With older engines avoid
damage to the valve cover and internal
injector cable harness by making sure
the mounting screws do not unscrew
from the cylinder head during removal.
Do not use impact tools to remove the
nuts securing the valve cover.

T2008279

Remove the bolts retaining the rocker
arm bridge between cylinders 4 and 5.
Remove the spring washer.

T2008278

Reinstall the front bolt without the
spring washer. Install bolt 9808001
with connector 9998338 into the rear
bolt hole and tighten both bolts.

Note: Bolt 9808001 must be used. It
has been modified and is shorter than
the previous version and does not use
a sleeve.

9998338

Remove the valve cover stud located
between no. 4 and 5 injector solenoids.

Note: Use Kent Moore tool J–41203 to
remove the stud on earlier D12 en-
gines.

J-41203

Group 25

Troubleshooting

W2002199

Route the oil pressure hose through
the hole in the valve cover where the
stud has been removed. Connect the
oil pressure hose to connector
9998338.

Note: Check that connector 9998338
and the oil pressure hose do not ob-
struct the rocker arms. If necessary,
use cable ties to prevent the oil pres-
sure hose from being damaged by the
rocker arms.

7
Install the valve cover and make sure
the oil pressure hose does not interfere
with any part of the valve mechanism.

T2007003

Tighten the valve cover nuts to
30 ± 3 Nm (22 ± 2 ft-lb). Follow the
tightening sequence shown.

30 ± 3 Nm
(22 ± 2 ft-lb)

W2002200

Install the seal for the oil pressure
hose into the hole in the valve cover.
Make sure the seal fits into the stud
hole in the valve cover.

W2002213

Route the oil pressure hose into the
cab as shown. Install pressure gauge
9998339

Note: Secure the oil hose with cable
ties to prevent kinks that would restrict
flow.

9998339

Group 25

Troubleshooting

Testing

1
Set the control switches to the OFF
position (VEB disabled). Start the en-
gine and measure the rocker arm shaft
oil pressure. The pressure should be
approximately 1 bar (14.5 psi).

2
If the pressure fluctuates or is under
0.5 bar (7.25 psi) or over 1.5 bar
(21.75 psi), the control valve is faulty.

Note: Low oil pressure in the rocker
arm shaft may also be due to exces-
sive wear in the rocker arm bushings
and/or the rocker arms which result in
excessive oil pressure loss. See
“Rocker Arm Roller, Checking” page
46.

3
Install the equipment for measuring
the exhaust gas temperature, including
the 36-pin breakout box. See “Exhaust
Temperature, Checking” page 40.

Removal

1
Set the parking brake. Remove the
pressure gauge and oil pressure hose
from the cab. Cut the oil hose free
from the cable ties and disconnect the
pressure gauge.

T2006731

Remove the valve cover.

CAUTION

With older engines avoid damage to the valve cover
and internal injector cable harness by making sure the
mounting screws do not unscrew from the cylinder
head during removal. Do not use impact tools to re-
move the nuts securing the valve cover.

3
Remove the oil pressure hose from
connector 9998338. Pull the oil pres-
sure hose through the valve cover and
remove the oil seal.

T2007708

Remove connector 9998338 and bolt
9808001 from the rocker arm shaft. In-
stall the spring washer and the two
rocker arm bridge bolts.

Content .. 7 8 9 10 ..