CRANKSHAFT AND BEARINGS - TM-10-3930-607-150049

ENGINE

CRANKSHAFT AND BEARINGS

1. Using a puller, remove pulley from crankshaft.

Take out screws and remove gear cover. Drop the oil

pump by removing nut or capscrews holding pump to

center main bearing cap, (Fig. 34)

Figure 35.

Figure 34.

2. Remove each main bearing cap, one at a time,

and inspect the bearing and crankshaft Journal.

Figure 36.

a. If there is any indication of flaking out,

scoring or actual wear, the bearing must be replaced.

NOTE:

However, tri-metal bearings, when new, are smooth and

highly polished. A few hours of operation will change

Bearing thickness wear must not

their appearance completely. The bearing surface

exceed more than ,0005 inch.

becomes a leaden gray in color and develops minute

craters, almost cellular in appearance as indicated in

a. To remove the upper half of the main

Figure 35. This appearance is a natural characteristic of

bearing shell, use a special tool which is a pin with an

this type bearing and in no way indicates failure.

angular head.

b. Insert the pin in the oil hole of the

3. If the visual inspection appears satisfactory, the

crankshaft. (Fig. 37) As the crankshaft is turned in a

bearings should be removed and checked for thickness

clockwise direction, the head of the pin will pick up the

using a ball micrometer. (Fig. 36)

bearing shell and force it out of the bore in the block.

The bearing can be replaced by reversing this removal

procedure. (Fig. 38)

4. If visual inspection of the crankshaft shows no

indication of excessive wear or scoring, the clearance of

the bearing should

B-12