GMC 1976 ZEO 6083 Maintenance Manual page 308

2. Remove the oil pump to rear main bearing cap
attaching bolts, then remove rear oil deflector, then
remove pump and drive shaft extension .
DISASSEMBLY (FIGURE 38)
1 . Remove the oil pump drive shaft extension .
NOTE :
Do not attempt to remove the washers
from the drive shaft extension. The drive shaft
extension and washers must be serviced as an
assembly. See Figure 39 .
2 . Remove the cotter pin, spring and the pressure
regulator valve.
NOTE:
Position thumb over pressure regulator
bore before removing cotter pin, as the spring is
under pressure .
3. Remove the oil pump cover attaching screws
and remove the oil pump cover and gasket .
4. Remove the drive gear and idler gear from the
pump body .
INSPECTION
Check the gears for scoring or other damage . If
they are damaged, new gears should be installed.
During assembly, the gear end clearance should be
gauged. Proper end clearance is .0025" to .0065" .
Also check the pressure regulator valve, valve spring
and bore for damage . Proper valve to bore clearance
is .0025" to .0050" .
ASSEMBLY
1 . Install the drive gear into the pump with the
hex ID of the drive shaft toward the oil pump mount-
ing pad, then install the idler gear .
Figure 38-Oil Pump Exploded View
INSTALLATION
Figure 40-Oil Pump Installation
ENGINE 6A- 4 3
Figure 39-Oil Pump Shaft Extension
2. Position a new gasket on the pump body and
install the oil pump cover. Tighten the cover screws
to 8 ft . lbs.
3 . Position the pressure regulator valve into the
pump cover, closed end first, then install the spring
and retaining pin.
NOTE :
When assembling the drive shaft exten-
sion to the drive shaft, the END OF THE EX-
TENSION
NEAREST THE
WASHERS
MUST BE INSERTED INTO THE DRIVE
SHAFT.
1 . Insert the drive shaft extension through the
opening in the main bearing cap and block until the
shaft mates into the distributor drive gear .
2. Position pump onto the rear main bearing cap
replace rear oil deflector and install attaching bolts.
Torque bolts to 35 ft . lbs. See Figure 40 .
3 . Install the oil pan. Refer to "Oil Pan" installa-
tion earlier in this section.