Figure 5-57. Crankshaft and main bearings.

inch. At installation use undersize main and

connecting rod bearings.

(3) After grinding, clean the crankshaft

thoroughly. Check for runout with a dial indicator.

If crankshaft runout exceeds 0.008 inch, replace

the crankshaft.

(4) Inspect the crankshaft gear for cracks,

broken teeth, burrs, scoring and wear. Remove

burrs and light scoring with a soft hone or crocus

cloth or replace the gear if necessary.

d. Reassembly.

(1) Position the key in the crankshaft. Using a

hydraulic pump, press the crankshaft gear onto the

crankshaft.

(2) Install the crankshaft in the block. Align

the crankshaft gear as instructed in paragraph 5-

29.

(3) Install the bearing liners and lubricate the

inside surfaces of the bearings. Rotate the upper

bearings into position in the reverse order of

removal. Ensure that bearings are installed in the

same positions they were removed from.

Figure 5-57. Crankshaft and main bearings.

(4) Install the lower bearing caps and secure

(8) Grasp the bearing cap at the recessed

with nuts. Tighten the nuts to a torque of 155 foot-

portion and pull outward. Tap the cap lightly with

pounds.

a soft hammer to aid in removal.

(5) Check the bearing clearance (subpara e)

and the crankshaft end clearance (subpara f).

NOTE

M a r k the upper and lower caps for location.

(6) Install the oil pump (para 5-24) and oil

pan and oil pan plate (para 5-25). Install the

(9) Place a main bearing removal tool in the

flywheel and housing (para 5-32) and timing gear

drilled oil hole of the crankshaft journal. Rotate the

cover (para 5-29). Install the water pump (para 5-

crankshaft and roll out the bearing upper half. Roll

6).

out the bearing tab end first. Remove the liners

(7) Install the engine in the tractor (para 2-8).

from the bearings.

e. Main Bearing Clearance Check.

(10) Cover the bearing cap studs with rubber

hose or cloth to protect the crankshaft when it is

NOTE

removed.

If bearing clearance is checked while the crankshaft is

(11) Lift the crankshaft from the engine.

installed and the engine is upright, hold the crankshaft

Lubricate and wrap the bearing surfaces.

against the upper halves of the bearings.

(12) Using a hydraulic puller, pull the

(1) Place a soft lead wire between the lower

crankshaft geat from the crankshaft. Remove the

bearing half and the crankshaft. Coat two 1-inch

key.

lengths of the wire with grease and place them

b. Cleaning. Clean the crankshaft and bearings

diagonally on the bearing. The grease will hold the

with cleaning solvent (Fed. Spec. P-D-680) and dry

wires in position.

with clean, lint-free cloths. Clean the oil holes in the

( 2 ) Turn the crankshaft one complete

block and ensure that the block is clean.

revolution.

c. Inspection and Repair.

(3) Remove the bearing cap and measure the

(1) Insect the bearing caps for burrs and

thickness of the compressed wire u s i n g a

high spots. Smoot surfaces with a soft hone or

micrometer. Clearance should be 0.0030 to 0.0059

crocus colth. Scratches on the bearig surfaces will

inch. Replace bearings if the proper clearance is not

not impair operation. Replace beaings if the

obtained.

surface is excessively rough and abrasive. If one

f. Crankshaft End Clearance Check.

bearing is replace, replace all bearings if possible.

(1) Push the crankshaft as far as it will go to

(2) Check the main bearing journals with a

one end of the cylinder block.

micrometer for out-of-round condition or excessive

( 2 ) Using a thickness gage, measure the

wear. If crankshaft journals are worn more than

c l e a r a n c e between the machined face of the

0.008 inch, g r i d the journals with precision

crankshaft flange and the flange of the lower half of

equipment, checking diameter frequently with a

micrometer. Grind the journals undersize 0.030

5-78