Thrust
washers (Figure 11B-86), on
each side of the rear main bearings, ab-
The lower
sorb the crankshaft thrust.
h a l v e s of the two-piece washers are dow-
e l e d t o t h e b e a r i n g cap; t h e u p p e r
h a l v e s are not doweled.
Main bearing trouble is ordinarily indi-
cated by low or no oil pressure. All of
the main bearing load is carried on the
lower bearings; therefore, wear will oc-
cur on the lower bearing shell first.
The condition of the lower bearing shells
may be observed by removing the main
bearing caps.
F i g u r e 11B-87. Removing Main Bearing
If main bearing trouble is suspected, re-
move the oil pan, then remove the main
Cap
bearing caps, one at a time, as outlined
A. To remove all except the rear main
b e l o w and examine the bearing shells.
bearing shell, i n s e r t a 1 / 4 " x 1 " b o l t
with a 1/2" diameter and 1/16" thick
head (made from a standard bolt) into
Remove Main Bearing Shells (Crankshaft
the crankshaft journal oil hole. Then
i n Place)
revolve the shaft to the right (clock-
wise) and roll the bearing shell out of
The bearing caps are numbered 1, 2, 3,
position as shown in Figure 11B-88 on
etc., indicate their respective position
page 11B-58.
The head of the bolt
and when removed, must always be rein-
must not extend beyond the outside
stalled in their original position.
diameter of the bearing shell.
All crankshaft main bearing journals, ex-
cept the rear journal, are drilled for an
B. Remove the rear main bearing upper
Therefore, the procedure
oil passage.
shell by tapping on the edge of the
for removing the upper bearing shells
bearing with a small curved rod, re-
with the crankshaft in place is somewhat
volving the crankshaft at the same
different on the drilled journals than on
time to roll the bearing shell out as
in
Figure
11B-89
on
page
the rear journal.
shown
11B-58.
Remove
the main bearing shells as
follows:
C. T h e l o w e r h a l v e s o f t h e c r a n k s h a f t
thrust washers will be removed along
1. Drain and remove the oil pan to ex-
with the rear main bearing cap. The
p o s e the main bearing caps.
upper halves of the washers can be
removed for inspection by pushing on
2. Remove the oil pump and the oil inlet
the ends of the washers with a small
a n d outlet pipe assemblies.
rod, forcing them around and out of
the main bearing support.
NOTE
If shims are used between the oil
pump and the main bearing caps,
Inspection
s a v e the shims so that they may be
reinstalled in exactly the same lo-
Bearing failures may result from deteri-
cation.
oration (acid formation) or contamination
of the oil or loss of oil. An analysis of
the lubricating oil may be required to de-
termine if corrosive acid and sulphur are
3. Remove one main bearing cap at a time
present which cause acid etching, flak-
(Figure 11B-87) and inspect, the bearing
i n g a n d p i t t i n g . B e a r i n g seizure may be
"Inspection" .
shell as outlined under
d u e to low oil or no oil.
Reinstall each bearing shell and bearing
cap before removing another bearing
Check the oil filter elements and replace
cap:
them if necessary.
Also, check the oil
E n g i n e (Less Major Assemblies)