TM-9-2815-202-34 Technical Manual for 8V71T Engines for M109 Howitzer Download
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TM 9-2815-202-34 (5) Inspect rear end of crankshaft at area of oil seal contact surface for evidence of rough or grooved condition. Slight ridges on crankshaft oil seal contact surface may be cleaned up with crocus cloth. If crankshaft cannot be cleaned up satisfactorily, reposition oil seal in flywheel housing. (6) Check crankshaft thrust surfaces for excessive wear or grooving. If only slightly worn, surfaces may be dressed with an oil stone. NOTE ● ● (7) (8) Minute cracks can be detected by using Magnetic Particle Inspection Method. Crankshaft failures are rare and when one cracks or breaks completely, it is very important to make a thorough inspection for contributory factors. Inspect crankshaft for fatigue cracks which start at an oil hole and follow journal surface at an angle of 45 degrees to axis. Reject crankshaft with cracks. Inspect main bearing shells for bright spots on backs indicating movement in bearing caps or supports. Discard shells if this condition is present. CAUTION Install all upper and lower bearing shells as a set. Do not replace one main bearing shell alone. When new crankshaft is used, install all new bearing shells. 4-155