Removal (Crankshaft in Place).

TM 10-393-242-34

halves are doweled to the bearing cap, the upper

h a l v e s are not doweled.

b. Removal (Crankshaft in Place).

(1) Remove the engine (para 2-5).

( 2 ) Remove the oil pan to expose the main

bearing caps (para 3-24).

( 3 ) Remove the oil pump inlet pipe and

s c r e e n assembly (para 3-25),

( 4 ) Remove all except the rear main bear-

ing, dress down the head of a 1/4" x 3/4" bolt to a

thickness of 1/16". (The thickness of the dressed

down bolt head, must be less than the thickness

o f the bearing shell). Insert the bolt into the

crankshaft journal oil hole and revolve the

c r a n k s h a f t so that the bolt head contacts the

b e a r i n g shell opposite the bearing locating tang

and roll the bearing out of the block.

NOTE

Remove one main bearing cap at a time, inspect as

outlined under INSPECTION in this section, and

complete replacement of shell and reinstallation of

cap before another cap is removed.

(5) Two-piece thrust washers are used on

e a c h side of the rear main bearing (fig. 359).

The lower half of these washers will be removed

when removing the rear main bearing cap;

upper half can be removed by pushing on end of

w a s h e r with a small rod, thus forcing washer

around and out on opposite side of bearing.

(6) Remove rear main bearing upper shell

Figure 3-60. Removing rear main bearing upper shell

(crankshaft in place).

by driving on the edge of the bearing shell with

a small curved rod (fig. 3-60) at the same time

revolving the crankshaft, thus rolling the shell

from its position.

c. Cleaning and Inspection.

(1) After removal, clean the bearing shells,

thoroughly, with P-D-680, or equal, and dry. In-

s p e c t them for scoring, pitting, flaking, chip-

ping, cracking, loss of babbitt, or signs of over-

heating. If any of these defects are present, the

b e a r i n g s must be discarded. However, the bab-

b i t t plated bearings may develop minute cracks

or small isolated cavities on the bearing surface

d u r i n g engine operation. These are characteris-

t i c s of and are not detrimental to this type of

bearing. The bearings should not be replaced for

t h e s e minor surface imperfections since func-

t i o n i n g of the bearings is in no way impaired

a n d they will give many additional hours of

trouble-free operation. The lower bearing shells,

w h i c h carry the load, will normally show signs

of distress before the upper shells do.

(2) Inspect the back of the bearing shells for

b r i g h t spots that indicate they have been mov-

Figure 3-59. upper and lower main bearing sheels, bearing

ing in the caps or cylinder block. If such spots

caps, and rear main bearing thrust washers.

a r e present, discard the bearing shells.

3-70