Tractor Repair: thrust bearing, thrust bearing, metal shavings

Question
I am restoring a Farmall 560.  I have rebuilt the engine and after it ran for 5-10 minutes the thrust bearing had extensive wear.  It looks like the crankshaft is being pushed forward toward the radiator end of the tractor.  The engine locked up the first time.  The second time the engine got really tight and there was metal shavings in the oil pan.  What do you think the problem is?  Thanks for any help you give.

Answer
Hello,

  It's kind of hard to say without knowing what was done and what parts were installed.  I have seen bearing kits that had the wrong parts in them, bearings that had the wrong size marked on them, and crankshafts that were ground incorrectly.  Recheck that all the parts are correct and are correctly installed.  If the engine was removed for the overhaul, something may have gone wrong when the engine was installed again.  The clutch puts forward pressure on the crankshaft when the pedal is pushed, but excessive pressure could be forcing the crankshaft forward with more force than the thrust bearing can take.  The clutch disk must be perfectly aligned with a pilot tool so that the input shaft goes in OK.  The halves of the tractor should go together without having to pull them together with the bolts.  If no problems are found with the bearings or crankshaft, then I would suggest splitting the tractor to recheck the clutch.