Decision on Replacing M Transm. Driving Shaft Bearings

Tom in OR · Apr 15, 2021

Everything is apart, clean and ready to put back together. Replaced transmission front main shaft and counter shaft seals, throw out bearing, clutch disk, etc. on '50 M. Noticed that there is some slop in the transmission driving shaft ball bearings. After studying parts book exploded views, it appears to be easy to replace the two ball bearings on the short driving shaft.

Question is, however, with a pilot bearing on the nose of the main shaft that inserts into the rear of the driving shaft, can this pilot bearing be re-inserted into the rear of the driving shaft, blind and by feel, without removal of transmission top cover? It seems that if the main shaft would move out of alignment, even slightly, it might be pretty much impossible to reinsert that pilot bearing into the rear of the driving shaft.

Has anyone accomplished this maneuver or had any 'positive' experience doing this? Project is on temporary hold!

Thanks for any advice you may have!!

shaun wallace · Apr 15, 2021

I replaced them bearing on a H thru bottom. did not remove top. Was couple years ago so dont remember how did it.

TedinNE · Apr 15, 2021

Put a rubber band around the bearing rollers it will go in ok. Would replace the old bearing. You can take off the belt pully cover and see it go in. Not really necessary.

CenTex Farmall · Apr 15, 2021

It will go back on without much trouble. There will still be wiggle room from play in the main shaft rear bearing. If you have an assistant available it won't hurt to pull the belt pulley (or sheet metal cover) and be able to work the main shaft a little while the input shaft is re-installed.

On the ones of mine that I've worked on, every one of them had plenty of wear in the input shaft assembly bearings. Those, the pilot bearing and the rear main shaft bearing all work together. Usually the one at the back is not nearly as loose. Good idea to consider replacing the pilot bearing as well. With the front two wiggling around it will get worn faster too. All are standard metric bearings. For the pilot bearing I've seen them both with the rollers captured in the outer race and caged on the inner race.

On one M that I use a lot, when I was in there I replaced the pilot bearing with a self aligning bearing with barrel shaped rollers from SKF. It will tolerate several degrees of misalignment. I wanted to experiment with and see if it would hold up and stay quiet. So far so good.

Decision on Replacing M Transm. Driving Shaft Bearings

Tom in OR

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shaun wallace

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TedinNE

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CenTex Farmall

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