GMC 4000 Series Service Manual page 282

Figure 2 2 — Rem oving Oil Seal Upper Half (Typical)
INSTALLATION
1. Align oil pump drive shaft to match with
distributor tang, then install oil pump to block,
positioning flange over distributor lower bushing.
Use no gasket. Attach suction pipe support with
bolt.
NOTE: Oil pump should slide easily into place,
if it does not, remove and reposition shaft slot to
align with distributor tang.
2. Install oil pan as instructed previously.
CRANKSHAFT REAR OIL SEAL
REPLACEMENT
REMOVAL
The rear main bearing oil seal can be replac­
ed (both halves) without removal of the crankshaft.
NOTE: Always replace the upper and lower
seal as a unit. Install with the lip facing toward
the front of the engine.
1. With the oil pan and oil pump removed, re­
move the rear main bearing cap.
2. Remove oil seal from the groove by prying
from the bottom with a small screwdriver (fig. 21).
3. Use light hammer and sm all brass pin
punch in manner shown in figure 22 to start seal
upper half out of block. When end of seal protrudes
far enough to be grasped with pliers, pull upper
half out of block.
INSTALLATION
1. Wipe crankshaft surface with clean cloth.
Apply engine oil on seal lip, but keep oil off part­
ing line surface as this surface is treated with
glue. P ress seal into place in bearing cap with
fingers.
2. Position seal upper half on crankshaft so it
can be installed in block by holding seal firmly
G M C S E R V I C E M A N U A L
Figure 2 3 — Sealer on Bearing Cap Area on Cylinder Block
with hammer handle while crankshaft is turned,
sim ilar to method used to install bearing.
brush-on type oil sealing compound to block and
mating surface on bearing cap. Do not apply sealer
on treated ends of oil seals.
with 10 to 12 foot-pounds initial torque, then use
lead hammer to tap crankshaft first rearward, then
forward. This will line up rear main bearing thrust
faces. Finally, tighten bearing cap bolts to 115
foot-pounds torque.
REMOVAL
hoses at radiator.
IATOR AND SURGE TANK (SEC. 13) of this manual.
ory drive pulley and belt. If so equipped, remove
retaining bolt.
puller screw to remove damper (fig. 24). Remove
tool from damper.
INSTALLATION
GASOLINE ENGINES
3. Referring to figure 23, apply light coat of
4. Install bearing cap and install cap bolts
5. Install oil pump and oil pan.
CRANKSHAFT DAMPER
REPLACEMENT
1. Drain radiator and disconnect radiator
2. Remove radiator core, as outlined in RAD­
3. Remove fan belt and (if so equipped) a cc ess­
4. Install Tool (J -6978-04) on damper and turn
CAUTION: The inertia weight section
of the damper is assembled to the hub
with a rubber-type material. The install­
ation procedures (with proper tool) must
be followed or movement of the inertia
weight section on the hub will destroy the
tuning of the damper.
Sec. 6A
Page 271
APPLY
SEALANT
TO SHADED
AREAS ONLY