Pilot bearing fit

Russ/40

Russ/40

Well-known member
I'm putting together a 39 transmission for my model A. I'm using a new input shaft, never fitted, and the pilot bearings i have (3 different ones ) will not slip on the pilot shaft. I have always made it a habit to use bushings instead of bearings and never had a problem. I anticipate a problem getting the shaft to fit the bearing when I try to put it all together. I cannot push the bearings on the pilot. Is this press fit correct?
 
Press fit is WRONG! The input shaft must be free to turn inside the pilot bushing when the clutch pedal is depressed. Something is definitely not right with either the finish on the input's snout, or the bushings are improperly sized. DD
 
If you have another input laying around check the figment of the pilot bearing on it. Whether it be a bearing or a bushing the I. D. Should be the same. Should slide on , not press fit. These days you must check everything.
 
New, or so called nos parts, do not always equate to being a good part. In some cases they were rejected parts that were never used in service, and left on a dealership's shelf, only to be found years later and assumed to be nos. Bottom line is....check your parts carefully before using.

Also, in the never ending debate on bushing vs. ball bearing for a pilot bearing, I favor the ball bearing...IF... it is a known good manufacturer's brand name bearing, not made in China, seals on both sides (not to be confussed with shields), and filled with a good known high temperature lube. I did a post on this here some years ago with pictures. Unfortunately, the ball bearing pilots Ford used in some of their early vehicles were shielded or open face ball bearings which failed early due to contamination getting into the ball and race area.

Just a couple of the many posts here on bearing vs. bushing. The second thread has pictures of bushings vs ball bearings, including some failed bushings that some say could not happen :D

https://www.fordbarn.com/forum/showthread.php?t=165420&highlight=pilot+bearing+bushing

https://www.fordbarn.com/forum/showthread.php?t=46288&highlight=pilot+bearing+bushing
 
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that bearing must slide on by hand or you will have a heck of time putting the ****** on the motor. your new input shaft must be too big! measure some others in your stash and see what the difference is
 
To restate, my concern is with a ball bearing, of which I have 3. The pilot OD is identical to the bearing I'D. Perhaps the problem is with the finish of the pilot.
 
What are the brgs & their #s. I believe the ID of the brg should be 17mm.I'm not sure about the OD on your A flywheel.
 
Size on Size is a press fit, that won't work, as you know. You should be able to polish down the pilot about .0015 with some emory cloth.
 
I use a Consolidated #361202-2rs. Double sealed. A bit pricey. 10 years ago it was $36.
I got it at IBT. A lot of miles later it is still going strong.
 
The pilot bearing is a standard metric bearing with a 17mm bore. The bearings will be sized to a very tight tolerance. If the input shaft does not slip in, as the input is new I would suspect it is not sized correctly. Do you have another shaft you could try the bearing on? Or do you have a means of measuring the shaft accurately?

I would agree with the suggestion above that the input could be polished. If you have access to a lathe the task would be much simplified.

Mart.
 
Kube said:
I always use bearings vs. a bushing.
Click to expand...

X2 I just installed one from Speedway. I removed the seals and used corn head grease on the bearings and put the seals back on. Careful not to use too much grease, it WILL get flung out!
 
B-O-B said:
What are the brgs & their #s. I believe the ID of the brg should be 17mm.I'm not sure about the OD on your A flywheel.
Click to expand...

Bearing numbers are as such:
6203 vvc3
6203 2rsj
6203 2rsc3

I'll put the shaft in my lathe and polish it a bit.
 
The consolidated bearing is a 15mm bore. What is the diameter of the shaft? Bearings are available with inch bore and metric OD and Width (thickness). Motion Industries https://www.motionindustries.com has tons of sizes listed.

I have replaced hundreds of bearings in machines over the years, and have discovered that the bearing needs to be a press fit to the shaft or the housing, but not both. Generally, press fit to housing, then hand press to shaft. The bearing has to be tighter than a slip fit on the shaft or the shaft will spin in the bearing under load.

I heat the housing with a heat gun or light bulb and chill the bearing in the freezer-bearing will drop right into the housing with minimal persuasion. The bearing will warm up from the heated housing-I chill the shaft, and it will drop in place with no persuasion if the fit is correct. Once everything cools and stabilizes, the bearing should be difficult to hand remove from the shaft and impossible to hand remove from the housing. That's the best description I can give as to how a properly fitted bearing "feels".

I assume that the same rules apply here.

John
 
i have a v8 trans in one of my A's, its a nice upgrade after you get your leg trained to stop trying to double clutch!
 
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