Pilot bearing fit
 

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?

Re: Pilot bearing fit
 

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

Re: Pilot bearing fit
 

Ok, I read the OP as using bearings not bushings. Is that correct?

Re: Pilot bearing fit
 

Use a bushing !!

Re: Pilot bearing fit
 

tag man has it right use a bushing.

Re: Pilot bearing fit
 

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.

Re: Pilot bearing fit
 

https://www.verntardel.com/collectio.../pilot-bushing

Tardel's site has them pretty reasonably priced.

Re: Pilot bearing fit
 

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/showt...earing+bushing

https://www.fordbarn.com/forum/showt...earing+bushing

Re: Pilot bearing fit
 

that bearing must slide on by hand or you will have a heck of time putting the tranny on the motor. your new input shaft must be too big! measure some others in your stash and see what the difference is

Re: Pilot bearing fit
 

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.

Re: Pilot bearing fit
 

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.

Re: Pilot bearing fit
 

Good catch, Seery! I blew that one bigly! DD

Re: Pilot bearing fit
 

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.

Re: Pilot bearing fit
 

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.

Re: Pilot bearing fit
 

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.

Re: Pilot bearing fit
 

I always use bearings vs. a bushing.

Re: Pilot bearing fit
 

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!

Re: Pilot bearing fit
 

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

I'll put the shaft in my lathe and polish it a bit.

Re: Pilot bearing fit
 

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

Re: Pilot bearing fit
 

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!

Re: Pilot bearing fit
 

a 6203 is 17mm Bore 40mm OD 12mm Width.

17mm bore =.66929"

What is the diameter of the shaft? A dial caliper will be accurate enough, unless you have a micrometer.

Re: Pilot bearing fit
 

I'm in the bearing business as a sales engineer for a major manufacturer.
You would think pilot bearings are more accurate and harder to align and
less tolerant of mis-alignment. Not always the case though.
Although not a flathead application, I recently battled reinstalling a
transmission using a pilot bushing (NOS and miked), where it previously
had been installed using a pilot bearing. It was a major PITA to slide that trans in place. I ended up making two studs for the bottom two transmission
mounting holes to guide the trans in place. Didn't need that kind of accuracy when I did the trans last time (when the pilot bearing was in the crank).

Re: Pilot bearing fit
 

Interestingly, 6203 is also a Delco (12si) alternator front bearing.
There's one sitting on my desk right now.

Re: Pilot bearing fit
 

That "203" bearing is one of the "MOST-USED" bearing sizes in thousands of applications across the planet! DD

Re: Pilot bearing fit
 

If I recall correctly, it is one and the same as the bearing used in the front of the generator on our old Fords as well.

Re: Pilot bearing fit
 

hulleywoodworking's comments make sense to me, as his points logicaly describe how a bearing functions. The OD of the bearing is a press fit in the flywheel, and the pilot shaft needs to be tight enough to allow the center of the bearing rotate. If the pilot turns in the center of the bearing, it will wear the nose of the pilot shaft. This quandary is why I have always used oilite bushings. I will polish the pilot shaft, and see how it feels. Henry must have had a good reason for using ball bearings there.

Re: Pilot bearing fit
 

Which brand of bearings are made in the USA? So far I have three different brands of(203) made off shore.

Re: Pilot bearing fit
 

I don't know what brands are USA made. I usually use Japanese made Nachi bearings; I've had good luck with them.

John

Re: Pilot bearing fit
 

At the place I work, we use pretty well exclusively SKF bearings. These are a quality world famous brand of bearings. Interesting that the packaging always states country of manufacture. I've seen and used SKF bearings from Sweden [obviously], and all sorts of countries including China and India! Doesn't seem right- Chinese made SKF bearings. But, never seen USA manufactured SKF's!
As coop stated; 6203 series is probably about the most commonly used bearing globally.

Re: Pilot bearing fit
 

To add to what John Hulley has written; as he says, engineering practice dictates that one surface is a press fit, whereas the other is a slip fit. The rule is; if the housing is fixed and the spindle rotates, the press fit will be on the spindle.
Conversely, if the spindle is fixed, and the housing rotates, the press fit is in the housing.
Think he front hubs on your Ford; the bearings are a press fit in the hub [which rotate], and a slip fit over the stub axle.
Whereas, in the transmission, the shafts turn, consequently the press fit of the bearings is on the shafts, and the bearings are a slip fit into the housing.

Re: Pilot bearing fit
 

High quality 6203's are from Japan. Many of the rollers around those sizes
are as well. ABECs too. (NSK, Nachi, NTN, etc.)
I work for NTN (Osaka), our US headquarters is in Mount Prospect IL.
A number of years ago we purchased most of the old Federal Mogul manufacturing facilities back East (Elgin IL, Macomb IL, Hamilton AL, etc.)
when FM decided to cease US production and source EVERYTHING offshore.
We build our stuff in those old facilities, under the BCA & Bower trade-names, since we bought rights those too.
We are one of the only bearing manufacturers in the US. Most of our automotive hub line is produced in Elgin. (OE and aftermarket)
Timken, Schaeffler/INA, FAG also does some production here in the USA as
well. Much of their stuff is sourced globally however.

Re: Pilot bearing fit
 

End result, I took about .001 off the Pilot shaft for a good push fit. I'm happy with it.

Re: Pilot bearing fit
 

I know I'm not going to change any minds with this post but I look at this pilot bearing versus bushing from a different perspective. Some of the helicopters I've worked on over the years have a lot of rotating ball bearings. There are also oscillating ball bearings but that is another story. The shelf life on the synthetic grease the manufacturer calls out is 4-years. As a safety factor, we have to reservice and inspect these bearings every 24-months. Some bearings make there life and some don't and that mostly is affected by the environment the helicopter is operated and stored in. Bearings will corrode when the grease gets displaced and moisture gets in through condensation or even trips through the car wash by owner/operators that don't like grease all over the place. They even corrode between the inner race ID and the shaft sometimes and that would be affected by a loose fit on the shaft.

For a pilot bearing, the thing only spins when the clutch is disengaged or when there is clutch slippage. If a person drives on the highway a lot, the bearing won't rotate as much as when the car is driven short distances like when just cruising around town. The bushing was thrown into the mix when mechanics complained about the bearings getting stuck on the pilot stub and the motor won't come away from the transmission during maintenance. The bushing is more forgiving in this case and its phosphor bronze make up (somewhat porous) allows it to absorb some lubricant when heated in a pan with some lube. Most folks don't even lubricate the bushing

My own opinion is that the ball bearing should be serviced at some scheduled interval that will allow it to remain in serviceable condition but that schedule depends on how the car is operated. The bushing should also be lubricated at some interval and the same conditions apply to it as the bearing. Folks that don't drive a lot can run a bushing and not worry as much about service at 10-years like a ball bearing and that's why the bushings are out there. When you replace the clutch or throw out then the pilot (either type) should also be replaced and the new part well lubricated. Apple and an orange.

Re: Pilot bearing fit
 

Rotorwrench, I totally agree with your comments, and thank you for your input. I come to the conclusion that the bushing is the superior solution. Failure of either, to me anyway, would favor the bushing over the ball bearing. The failure of a ball bearing will have more troublesome consequences, IMHO.

Re: Pilot bearing fit
 

i have removed some terribly worn out bushings that still were working just fine

Re: Pilot bearing fit
 

Years ago I attended a seminar on bearings. The thing I took away from that class was that the quality control for common bearings is 10% failure. Bearings used in aircraft are subject to more stringent quality control and also higher price, much higher price. The 203 bearing in rotor wrench's chopper must meet greater tolerance standards than ford generators.
Bruce

Re: Pilot bearing fit
 

Pretty sure all the French military motors have bushings. That must mean something.

Mart.

Re: Pilot bearing fit
 

A Hughes tech rep once told me that the bearings we were using on the helicopters were rounder than the same bearing used in industry. I loved the guy (tech rep) to death God rest him but I found out later from the manufacturer that the statement by cmbrucew is pretty close on this. The bearings are mainly just inspected and tested more per unit for tolerance and machining accuracy than their industrial counterparts. The balls aren't any rounder than the industrial ones but they are checked more often during manufacture to insure a closer tolerance. Most of the bearing assemblies are serialized now for tracking in case of premature failure and most also have life limitations that range from 200-hours to 3000-hours depending on design and type of service intended. These are bearings that rotate the whole time that the helicopter is turning the blades so they get a good work out.

The pilot bearing (ball type) likely doesn't work near as hard as the average rotating bearing but they do tend to stay in service for a lot longer by date and obviously there is no easy way to service them to insure proper function.The clutch makes dust and the linings & friction surfaces generate heat so it's not the easiest environment for a small bearing to live in.