Pilot bearing fit

LEM

LEM

Senior Member
Is the pilot bearing to the transmission input shaft Press fit? My brand new pilot bearing ID to Transmission input shaft seems to be a very tight press fit.
 
The pilot bearing is a press fit to the flywheel, but not a press fit to the input shaft of the transmission. If it was you would not be able to install the transmission.
 
Check the dimensions to see which part is wrong. Are you sure there are no burrs anywhere? it should be a slip fit on the transmission.
 
Does anyone have an idea what the transmission input shaft diameter should be?
My shaft is .696 diameter and my bearing is .667 ID.
 
Go find a bearing that fits. That was a very common one used on many makes and models of vehicles. My model A my tractor and a mustang I once owned had the same pilot bearing. How was the fit on the old bearing or did things get changed out? I went out and measured an A input shaft and see .6562. So what is your shaft out of? You apparently have the correct bearing for sure.
 
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I would take some emery cloth and sand the shaft. According to your measurements, you need about.029” I had a new nors shaft that wouldn’t go, and that’s what I did to get it to fit. Didn’t take much time to do.
 
IMHO, .029" is an awful lot of sanding. My choice would be to first side by side compare you have a compatible input shaft; which your problem suggests you dont.
Assuming it will work, go with the bronze bushing and size it as necessary.
 
LEM said:
Does anyone have an idea what the transmission input shaft diameter should be?
My shaft is .696 diameter and my bearing is .667 ID.
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Bratton's catalog description: TRANSMISSION MAIN DRIVE GEAR - U.S. made. The end of the shaft where the pilot bearing (11550) fits must be .668 diameter. If worn more then .002 (.666) then the shaft must be built up or replaced. A poor fit will cause the transmission to jump out of high gear. Will not fit Early 1928 transmission boxes.
 
goodcar said:
Bratton's catalog description: TRANSMISSION MAIN DRIVE GEAR - U.S. made. The end of the shaft where the pilot bearing (11550) fits must be .668 diameter. If worn more then .002 (.666) then the shaft must be built up or replaced. A poor fit will cause the transmission to jump out of high gear. Will not fit Early 1928 transmission boxes.
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Is your input shaft a new purchase from Brattons, since you reference them? If not and its an older used input shaft, someone must have repaired it to fit a bearing they had on hand. Either get the bronze bushing and ream to size or get a machine shop to turn it down to the proper size.
 
Russ/40 said:
Is your input shaft a new purchase from Brattons, since you reference them? If not and its an older used input shaft, someone must have repaired it to fit a bearing they had on hand. Either get the bronze bushing and ream to size or get a machine shop to turn it down to the proper size.
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I didn't purchase a new input shaft from Brattons. I merely posted the description exactly as it appears in their catalog.
 
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