Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 12-24-2019, 01:07 PM   #1
gw
Junior Member
 
Join Date: Oct 2018
Posts: 6
Default Pilot Bearing Question

The pilot bearing does not fit snugly on the trans input shaft. Measuring shows that the shaft is .002 smaller than the pilot bearing. Is this a problem? If so, could a brass shim ring be used?
gw is offline   Reply With Quote
Old 12-24-2019, 01:31 PM   #2
Werner
Senior Member
 
Werner's Avatar
 
Join Date: Jan 2019
Location: Germany, near Aachen
Posts: 784
Default Re: Pilot Bearing Question

Hallo gw,

if the shaft can move inside the bearing seats, this is not a good thing because the main bearing wears out faster. A brass sleeve is difficult to manufacture because the wall thickness is too small.

I minimized the movement by glue a steel strip (0.1 mm) round the pilot stump (Locktite).
Attached Images
File Type: jpg P1010727.jpg (46.7 KB, 50 views)
File Type: jpg P1010724.jpg (63.0 KB, 43 views)
__________________
Beste Gruesse aus Deutschland,
Werner


Ford Model A Roadster, 1928
Citroen 11 CV, 1947
Hercules NSU-Wankel Rotary Engine, 1976 (Canadian version)
Werner is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 12-24-2019, 02:51 PM   #3
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Upstate NY and western Florida
Posts: 5,532
Default Re: Pilot Bearing Question

I wouldn't worry about .002"
Patrick L. is offline   Reply With Quote
Old 12-24-2019, 02:58 PM   #4
Tom Endy
Senior Member
 
Tom Endy's Avatar
 
Join Date: May 2010
Location: Southern California
Posts: 2,605
Default Re: Pilot Bearing Question

During a transmission overhaul it is common to find most input shafts with the nose end worn. I take them to a local repair shop where they machine the nose down and press on a drill bushing of the proper size.

Tom Endy
Tom Endy is offline   Reply With Quote
Old 12-24-2019, 03:08 PM   #5
Russ/40
Senior Member
 
Russ/40's Avatar
 
Join Date: May 2010
Location: Santee, California
Posts: 3,192
Default Re: Pilot Bearing Question

Tom, your fortunate to be able to get those kind of services done for you. I suspect the volume of your work makes that more worthwhile for a machinist. Always enjoy seeing your posts.
Russ/40 is offline   Reply With Quote
Old 12-24-2019, 03:19 PM   #6
Joe K
Senior Member
 
Joe K's Avatar
 
Join Date: Jul 2010
Location: Cow Hampshire
Posts: 3,563
Default Re: Pilot Bearing Question

I would say 0.002 IS worth worrying about. One of the reasons for "jerky" engagement and walking the 3rd gear internal gear "off" the input shaft. (i.e. slipping out of 3rd back to neutral)

Best would be to turn it down, bush it back a tad oversize, and with emery cloth go for a "tight" fit.

Cheap insurance.

Joe K
__________________
Shudda kept the horse.
Joe K is offline   Reply With Quote
Old 12-24-2019, 04:18 PM   #7
Werner
Senior Member
 
Werner's Avatar
 
Join Date: Jan 2019
Location: Germany, near Aachen
Posts: 784
Default Re: Pilot Bearing Question

Quote:
Originally Posted by Tom Endy View Post
... I take them to a local repair shop where they machine the nose down and press on a drill bushing of the proper size.

Tom Endy
I was advised against that. Due to the thinner turning, the nose loses strength and can break due to torsional stress.
__________________
Beste Gruesse aus Deutschland,
Werner


Ford Model A Roadster, 1928
Citroen 11 CV, 1947
Hercules NSU-Wankel Rotary Engine, 1976 (Canadian version)
Werner is offline   Reply With Quote
Old 12-24-2019, 09:49 PM   #8
1928Mustang
Junior Member
 
Join Date: Mar 2019
Posts: 8
Default Re: Pilot Bearing Question

Any good machine shop can fix it. One way is to tig weld it up and turn it to size so bearing just slides on. I have done many this way.
1928Mustang is offline   Reply With Quote
Old 12-24-2019, 10:45 PM   #9
Mulletwagon
Senior Member
 
Mulletwagon's Avatar
 
Join Date: Jan 2019
Location: Florida Panhandle
Posts: 318
Default Re: Pilot Bearing Question

Quote:
Originally Posted by Patrick L. View Post
I wouldn't worry about .002"
I'm with Pat. Clearance of .002 is little more than a sliding fit. Not sure the mods described are warranted. For serious slop a new input shaft/pilot bearing would be more cost effective IMHO.
Mulletwagon is offline   Reply With Quote
Old 12-24-2019, 11:04 PM   #10
Chuck Sea/Tac
Senior Member
 
Chuck Sea/Tac's Avatar
 
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 1,882
Default Re: Pilot Bearing Question

They make a smaller inner diameter 6203. Metric I think. Turn the nose down and use that bearing. I’m rebuilding my transmission after 40,000 miles of this bearing. It’s worn a little more now, so were I to reuse the otherwise good input shaft, I would turn and sleeve back to standard, as Tom mentioned.
Chuck Sea/Tac is offline   Reply With Quote
Old 12-24-2019, 11:11 PM   #11
1ton
Senior Member
 
Join Date: Jun 2012
Location: North Aurora,Il.
Posts: 116
Default Re: Pilot Bearing Question

.002 clearance is fine but the pilot on your input shaft looks to be worn. How can you get a good measurement on that?
1ton is offline   Reply With Quote
Old 12-25-2019, 12:37 PM   #12
goodcar
Senior Member
 
Join Date: Apr 2013
Posts: 134
Default Re: Pilot Bearing Question

Quote:
Originally Posted by Patrick L. View Post
I wouldn't worry about .002"
As long as you have the transmission removed, fix it. .002 problem or not, shaft will continue to wear. Find a good machinist to weld and turn down or use a sleeve. Pulling and installing the transmission is no fun.
goodcar is offline   Reply With Quote
Old 12-25-2019, 12:52 PM   #13
Jim Brierley
Senior Member
 
Join Date: Jun 2010
Location: Temecula, CA
Posts: 3,254
Default Re: Pilot Bearing Question

I agree with Pat L and mulletwagon. .002" is miniscule, and the only time that brg. is turning is when the clutch is pushed down and the car isn't moving. Don't worry about it!
Jim Brierley is offline   Reply With Quote
Old 12-25-2019, 02:10 PM   #14
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Upstate NY and western Florida
Posts: 5,532
Default Re: Pilot Bearing Question

.002" is half thickness of a human hair and that of an engine crank bearing clearance.
Patrick L. is offline   Reply With Quote
Old 12-26-2019, 10:26 AM   #15
Ranchero50
Senior Member
 
Join Date: Aug 2019
Location: Hagerstown MD
Posts: 134
Default Re: Pilot Bearing Question

Gotta have some clearance or the input to bushing fit will seize while sitting at a stop light with the trans in gear and the clutch held.
__________________
Building a '29 Speedster, the hard way...
Ranchero50 is offline   Reply With Quote
Old 12-26-2019, 10:59 AM   #16
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Upstate NY and western Florida
Posts: 5,532
Default Re: Pilot Bearing Question

While most vehicles use a bushing for a pilot 'bearing', most Model As use a ball bearing. I have seen a couple old Fords with a bushing though. A properly oiled oil-lite bushing would work just fine. As you mention, some extra clearance would be necessary.
Patrick L. is offline   Reply With Quote
Old 12-26-2019, 11:41 AM   #17
Werner
Senior Member
 
Werner's Avatar
 
Join Date: Jan 2019
Location: Germany, near Aachen
Posts: 784
Default Re: Pilot Bearing Question

Quote:
Originally Posted by Ranchero50 View Post
Gotta have some clearance or the input to bushing fit will seize while sitting at a stop light with the trans in gear and the clutch held.
For sure? I think the rolling movement when pedaling the clutch is taken over by the roller bearing?
Attached Images
File Type: jpg P1010850.jpg (62.5 KB, 20 views)
__________________
Beste Gruesse aus Deutschland,
Werner


Ford Model A Roadster, 1928
Citroen 11 CV, 1947
Hercules NSU-Wankel Rotary Engine, 1976 (Canadian version)
Werner is offline   Reply With Quote
Old 12-27-2019, 09:55 AM   #18
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 11,514
Default Re: Pilot Bearing Question

Push fit is anywhere from .001" to .0015". .002" is good for a rotational clearance that doesn't need to be a push fit. I've seen the V8 flywheels with the old phosphor bronze bushing worn egg shaped and they were still working albeit not as well as they should. Now if it was more than .002", then I'd start to get concerned. The input shaft bearing has clearance too or the bearings would last very long.

Rotating bearing fits have to have some clearance or there can be galling from excessive temperature built up. The only time the pilot really turns is when the clutch is released. Folks that stand on the clutch too long will experience more wear. Put the transmission in neutral and release the clutch.
rotorwrench is offline   Reply With Quote
Old 12-27-2019, 04:02 PM   #19
Werner
Senior Member
 
Werner's Avatar
 
Join Date: Jan 2019
Location: Germany, near Aachen
Posts: 784
Default Re: Pilot Bearing Question

That's true, if rolling bearings run under tension, they are quickly destroyed.

In my case, the worn undersize is 0.007"! This is extreme and the new main ball bearing would wear out quickly again.
__________________
Beste Gruesse aus Deutschland,
Werner


Ford Model A Roadster, 1928
Citroen 11 CV, 1947
Hercules NSU-Wankel Rotary Engine, 1976 (Canadian version)
Werner is offline   Reply With Quote
Old 12-28-2019, 04:09 PM   #20
Roger V
Senior Member
 
Roger V's Avatar
 
Join Date: May 2010
Location: Michigan
Posts: 1,554
Default Re: Pilot Bearing Question

I agree with Joe K (#6 post). Now is the time to correct the issue since it’s out. The shaft is going to turn in the pilot bearing as it has already so it’s going to wear smaller yet. As mentioned, getting it turned is easy for any machine shop. Also it seems most machinists have their own lathes at home and may do it for you. I’ve had them turned to 5/8” by a retired tool and die maker. The bearing originally was metric at 17 mm. That few thousandths will clean-up most shafts and has never been a problem strength-wise. You can buy bearings at most bearing shops. I get mine on Amazon Prime.
Roger V is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 11:32 AM.