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6A4-24
1977 PONTIAC SERVICE MANUAL
FLATTENED
GAUGING PLASTIC
4645
Fig.
6A4-62
Checking Bearing Clearances
AND PART NUMBER'
STAMPED IN THE
BEARING SHELL
3670
Fig.
6A4-63
Main Bearing Identification
2. Remove bearing cap and remove lower shell.
3. Insert a flattened cotter pin or roll out pin in the oil
passage hole in the crankshaft, then rotate the crankshaft in
the direction opposite to cranking rotation. The pin will
contact the upper shell and roll it out.
- -
4. The main bearing journals should be checked for
roughness and wear. Slight roughness may be removed with
a fine grit polishing cloth saturated with engine oil. Burrs may
be removed with a fine oil stone. If the journals are scored
or ridged, the crankshaft must be replaced.
NOTE: The journals can be measured for out-of-round
with the crankshaft installed by using a crankshaft
caliper and inside micrometer or a main bearing
micrometer. The upper bearing shell must be removed
when measuring the crankshaft journals. Maximum out-
of-round of the crankshaft journals must not exceed
.0015".
5. Clean crankshaft journals
and bearing caps
thoroughly before installing new main bearings.
6. Apply Special Lubricant, No. 1050169 or equivalent
to the thrust flanges of bearing shells on No. 3 bearing.
7. Place new upper shell on crankshaft journal with
locating tang in correct position and rotate shaft to turn it
into place using cotter pin or roll out pin as during removal.
8. Place new bearing shell in bearing cap.
9. No. 5 bearing
-
Install new asbestos oil seal in the rear
main bearing cap. (REAR MAIN BEARING OIL SEAL)
(Fig. 6A4-64) Install 1050805 or equivalent sealer on cap as
shown.
Fig.
6A4-64
Installing Rear Main Oil Seal
10. Install bearing caps, lubricate bolt threads with
-
.
engine oil, then install.
Torque Nos. 1 through 4 to 80 ft. Ibs. and No. 5 to 120
ft. lbs.
REAR M A I N BEARING UPPER OIL SEAL
Repair
Tools have been released to provide a means of
correcting engine rear main bearing upper seal leaks without
the necessity of removing the crankshaft. The procedure for
seal leak correction is listed below.
1. Drain oil and remove oil pan and rear main bearing
cap.
2. Insert Packing Tool BT-6433 against one end seal in
cylinder block and drive the old seal gently into the groove
until it is packed tight. This vaires from 1/4" to 3/4"
depending on the amount of pack required. (Fig. 6A4-65)
3. Repeat this on the other end of the seal in the cylinder
block.
4. Measure the amount the seal was driven up on one
side; add 1/16", then cut this length from the old seal
removed from the main bearing cap with a single edge razor
blade.
5. Place a drop of 1050805 Sealer or equivalent, on each
end of seal and cap as indicated.
6. Work these two pieces of seal into the cylinder block
(one piece on each side) with two small screwdrivers. Using
Packing Tool, pack these short pieces up into the block. Use
Seal Trimming Tool BT-6436 to trim seal flush with block
as shown in Fig. 6A4-66.
NOTE: Place a piece of shim stock between seal and
crankshaft to protect bearing surface before trimming.
7. Form a new rope seal in the rear main bearing cap
as outlined.
8. Assemble the cap to the block and torque to
specifications.
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