Crankshaft Main Bearing: Service and Repair

REMOVAL

1. Disconnect battery ground cable, then remove starter.
2. Remove oil pan and oil pump as previously described.
3. Remove main bearing cap attaching bolts. If bearing inserts are to be replaced with engine in vehicle, leave at least two main bearing caps tight while servicing others.
4. Remove main bearing caps and bearing inserts.
5. Using suitable tool, remove upper bearing inserts. Insert tool in crankshaft journal oil hole and turn crankshaft in normal direction of rotation to remove upper bearing half. Always turn crankshaft clockwise. Counterclockwise rotation may cause timing belts to jump time.
6. If bearing clearance is to be measured in vehicle using Plasti-gauge, support crankshaft with piece of wood and jack to avoid false reading.

Fig. 15 Main bearing cap installation:

INSTALLATION

1. After inspecting crankshaft for nicks, scoring and wear, measure crankshaft to select proper bearing to crankshaft clearance. Clearance should be .0008-.0026 inch (0.020-0.066 mm). Always keep two bearing caps tight while measuring others.
2. Install new bearings in caps and cylinder block, matching bearing tangs with notch in cap and block.
3. Using suitable tool, install upper bearing half.
4. Ensure that bearing caps are properly located, Fig. 15, torque cap bolts to 50-60 ft. lbs. After each cap is tightened, ensure that crankshaft can be rotated manually. If not, remove that bearing cap and identify source of interference.
5. Torque main bearing caps to 75-85 ft. lbs. and again check for crankshaft rotation.
6. Remove rear main bearing cap and apply a {1/8} inch bead of suitable sealant across main bearing cap to cylinder block surface. Do not apply sealant onto bearing or rear seal surface of crankshaft.
7. Install rear cap, torquing cap bolts to 75-85 ft. lbs. in two steps.
8. Install oil pump and oil pan.
9. Install starter, then connect battery ground cable.