MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
140
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
Fig. 4-2-8 Removing the vacuum pump
assembly
Fig. 4-2-9 Removing the camshaft bearing
cap
Disassembling the vacuum pump assembly
⑧
(1) Pull out the vacuum connecting hose from the
vacuum pump.
(2) Remove the 3 hexagon flange bolts (M6×20)
connecting the vacuum pump and cylinder head flange.
See Fig. 4-2-8.
(3) Remove the vacuum pump assembly from the rear
end of the cylinder head exhaust camshaft.
Disassembling the camshaft bearing cap
⑨
(1) Remove the 22 hexagon flange bolts (M6×35 and
M6×20) for fastening the camshaft bearing cap in the
order from the two sides of camshaft bearing cap
symmetrically to the center. See Fig. 4-2-9.
(2) Remove the camshaft bearing cap from the cylinder
head.
Fig. 4-2-10 Removing the intake/exhaust
camshaft
Disassembling
the
Intake/exhaust
camshaft
assembly
⑩
(1) Take out the intake/exhaust camshaft assembly
respectively from the cylinder head, as shown in Fig.
4-2-10.
(2) Remove the plug cover and the front oil seal of
camshaft.
(3) Check the front oil seal of camshaft and replace it if it
is damaged.
Inspection and repair
The parts should be adjusted, repaired or replaced if
any excessive worn or damage is detected during
inspection.
1. Checking the outer diameter of the
camshaft
journal
Use a micrometer screw to measure the outer diameter
of each camshaft journal from two sides
（①
and
②）
.
See Fig. 4-2-11.
Replace the camshaft if the measured value is below
Cylinder head
Vacuum pump
assembly
Cylinder head
Camshaft
bearing cap
Cylinder head
Camshaft
