Throw-out Bearing Problem?
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 849
Likes: 8
From: MANCHESTER IOWA
Throw-out Bearing Problem?
The throw-out bearing in my 64 was making noise when clutch was depressed. i was told that it was probably dry and just replace it. so, i replaced it with a new one. no noise for about a week and then it started doing it again. does something need ajusted? whats my problem?
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 849
Likes: 8
From: MANCHESTER IOWA
Originally Posted by C64BOB
Did your throw-out bearing feel rough as you turned it? Are you sure the noise isn't coming from the pilot bearing?
Burning Brakes
Joined: Aug 2005
Posts: 1,133
Likes: 2
From: Corona CA
Originally Posted by 64tux
don't know want pilot bearing is??? are they the same thing?? inch and a quarter bearing on transmission shaft?
They are not the same thing...the thowout bearing rides on the transmission snout..it is engaged by the clutch fork and presses against the clutch cover to release the clutch.
The pilot bearing is actually usually a bushing but some cars use a true roller bearing. It is located inside the back of the Crank Shaft. It is pressed in. Basically it centers the transmission input shaft in the crank shaft.
Did you inspect your clutch cover while you had things apart? How about the disk itself...I would guess if the noise was not the throwout bearing then maybe a spring in the clutch disk or cover is loose or something....
Darren
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 849
Likes: 8
From: MANCHESTER IOWA
Originally Posted by macdarren
They are not the same thing...the thowout bearing rides on the transmission snout..it is engaged by the clutch fork and presses against the clutch cover to release the clutch.
The pilot bearing is actually usually a bushing but some cars use a true roller bearing. It is located inside the back of the Crank Shaft. It is pressed in. Basically it centers the transmission input shaft in the crank shaft.
Did you inspect your clutch cover while you had things apart? How about the disk itself...I would guess if the noise was not the throwout bearing then maybe a spring in the clutch disk or cover is loose or something....
Darren
The pilot bearing is actually usually a bushing but some cars use a true roller bearing. It is located inside the back of the Crank Shaft. It is pressed in. Basically it centers the transmission input shaft in the crank shaft.
Did you inspect your clutch cover while you had things apart? How about the disk itself...I would guess if the noise was not the throwout bearing then maybe a spring in the clutch disk or cover is loose or something....
Darren
Burning Brakes
Joined: Aug 2005
Posts: 1,133
Likes: 2
From: Corona CA
That really sounds like something in the pressure plate or the clutch disk itself. I had a similar problem when I broke a spring on the clutch disk. When you press the pedal in you release the disk and it starts to rattle around, you let the pedal out just a bit and you allow the pressure plate to contact the disk that bit of friction tightens things up and the noise stops.
I would also be sure to check all the external linkage springs too, sometimes one of them stretchs and can make similar noises...they should all have some tension in them no matter the position of the pedal.
I suppose it is possible you have a worn pilot bushing that is allowing the trans input shaft to wobble a bit causing some noise somewhere and that again letting up a bit on the clutch pulls everthing together enough to stop it.
Either way unless it is one of the external springs you maybe be looking at pulling it apart again....
Darren
I would also be sure to check all the external linkage springs too, sometimes one of them stretchs and can make similar noises...they should all have some tension in them no matter the position of the pedal.
I suppose it is possible you have a worn pilot bushing that is allowing the trans input shaft to wobble a bit causing some noise somewhere and that again letting up a bit on the clutch pulls everthing together enough to stop it.
Either way unless it is one of the external springs you maybe be looking at pulling it apart again....
Darren
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 849
Likes: 8
From: MANCHESTER IOWA
Originally Posted by macdarren
That really sounds like something in the pressure plate or the clutch disk itself. I had a similar problem when I broke a spring on the clutch disk. When you press the pedal in you release the disk and it starts to rattle around, you let the pedal out just a bit and you allow the pressure plate to contact the disk that bit of friction tightens things up and the noise stops.
I would also be sure to check all the external linkage springs too, sometimes one of them stretchs and can make similar noises...they should all have some tension in them no matter the position of the pedal.
I suppose it is possible you have a worn pilot bushing that is allowing the trans input shaft to wobble a bit causing some noise somewhere and that again letting up a bit on the clutch pulls everthing together enough to stop it.
Either way unless it is one of the external springs you maybe be looking at pulling it apart again....
Darren
I would also be sure to check all the external linkage springs too, sometimes one of them stretchs and can make similar noises...they should all have some tension in them no matter the position of the pedal.
I suppose it is possible you have a worn pilot bushing that is allowing the trans input shaft to wobble a bit causing some noise somewhere and that again letting up a bit on the clutch pulls everthing together enough to stop it.
Either way unless it is one of the external springs you maybe be looking at pulling it apart again....
Darren
Burning Brakes
Joined: Aug 2005
Posts: 1,133
Likes: 2
From: Corona CA
Be sure to check the Clutch fork and it's adjustment...the throwout bearing should be disengaged from the clutch cover fingers when the clutch pedal up. If it lightly touchs the clutch fingers it might rattle.
Just another thing to look at. As I recall (and you should check this) but the fork needs to be pointing forward about 5 degrees just as the bearing meets the fingers. You should then also have some distance behind the bearing to allow it to slide back and be free of the fingers. There are specs for all this. If the problem just started and it has been find for a while I would again suspect those clutch spring if it started suddenly. If it started slowly suspect wear on the trans shaft, front carrier bearing, and/or the Pilot bushing.
Good luck, let us know what you find.
Darren
Just another thing to look at. As I recall (and you should check this) but the fork needs to be pointing forward about 5 degrees just as the bearing meets the fingers. You should then also have some distance behind the bearing to allow it to slide back and be free of the fingers. There are specs for all this. If the problem just started and it has been find for a while I would again suspect those clutch spring if it started suddenly. If it started slowly suspect wear on the trans shaft, front carrier bearing, and/or the Pilot bushing.
Good luck, let us know what you find.
Darren
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: Jan 2006
Posts: 1,096
Likes: 0
From: Horsetown USA (Norco) Kaleeforkneeah
Originally Posted by 64tux
how hard is it to get pilot bearing out?? pull engine? or just trany and bell housing?
You have to have the trans out. What I do is pack the backside of the bearing/bushing with grease, and get a piece of round bar, the same diameter as the hole (an old trans input shaft works well), and drive the bar in. It will cause the bearing/bushing to hydraulic out from the pressure build up behind it.
I think some other members here have had great (and less messy) success, tapping out the hole, and then using a long bolt, to drive it out. The bolt bottoms out against the back of the crank, and acts as a puller.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Originally Posted by Johns_65Vette
I think some other members here have had great (and less messy) success, tapping out the hole, and then using a long bolt, to drive it out. The bolt bottoms out against the back of the crank, and acts as a puller.
When you adjust the clutch, make sure you do it so you get the required 1" or so of pedal free play at the top of pedal travel, and the return spring is pulling the pedal all the way up against the rubber bumper. Inadequate pedal free play will cause the throwout bearing to be in contact with the clutch fingers, and it will fry in short order.
Also, make sure the throwout bearing is correctly installed on the clutch fork - both the fork AND the anti-rattle spring must be inside the groove in the bearing.
Burning Brakes
Joined: Aug 2005
Posts: 1,133
Likes: 2
From: Corona CA
you can also remove the pilot bearing with a 'slide hammer'...I'm not sure but I think that is the 'recommended' tool....In theory you could get it out without messing it up so you can inspect it to know if it was a problem, but they are so cheap, I'd never resuse one and in practice you probably won't get it out with no damage. However if you have a real bearing (not the stock style bushing) you kinda have to use the slide hammer as it is pretty hard to thread a bearing ... never tried John's hydraulic approach....
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 849
Likes: 8
From: MANCHESTER IOWA
After looking thing over and talking to some car guys my son runs with, i don't think it is the pilot bearing. they thought that i had to much travel from where the clutch disengaged to the floor. so i ajusted the engagement piont and know more clatter. they thought that the throwout bearing was going to far. does this make sense to you guys?
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
The ONLY important part of clutch adjustment is to set it for proper pedal free play with the pedal up against the rubber bumper - you should have 1" to 1-1/4" of free play when depressing the pedal before you feel resistance (throwout bearing contacting the clutch fingers). Ignore anyone who tells you to adjust it for some distance off the floor for the engagement point - those are the people who regularly replace their throwout bearing and wonder why.
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Originally Posted by 64tux
After looking thing over and talking to some car guys my son runs with, i don't think it is the pilot bearing. they thought that i had to much travel from where the clutch disengaged to the floor. so i ajusted the engagement piont and know more clatter. they thought that the throwout bearing was going to far. does this make sense to you guys?
It makes sense to me that the noise could have gone away because you have overtraveled the pressure plate and now that you're not callapsing as far, the noise is gone. The reason it makes sense to me is because I've been there. But.............................!
I didn't have the pedal stop under the dash to limit upward travel ('56 Chevy) so the clutch was coming up too high. I had the right free play but the free play was set at a higher pedal stroke and this was what overtraveled the pressure plate.
I mention this because you could have similar conditions. Check your pedal for the correct height off the floor. It should be close to the same as the brake pedal if you have manual brakes. If you've adjusted the clutch and have some free play and the noise is gone, I'd drive on and not worry about it.
Le Mans Master
Joined: Jan 2002
Posts: 8,913
Likes: 283
I can lightly feel the vibration of the clutch/PP contacting the bearing when I push the pedal down with my hand. Like JohnZ said, you need the 1'-1.25" top end free play. I use a tape measure, and push the pedal down with my hand and when I feel the slight vibration, I know the bearing is contacting the PP fingers.
Mark
Mark
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 849
Likes: 8
From: MANCHESTER IOWA
Originally Posted by JohnZ
The ONLY important part of clutch adjustment is to set it for proper pedal free play with the pedal up against the rubber bumper - you should have 1" to 1-1/4" of free play when depressing the pedal before you feel resistance (throwout bearing contacting the clutch fingers). Ignore anyone who tells you to adjust it for some distance off the floor for the engagement point - those are the people who regularly replace their throwout bearing and wonder why.
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Originally Posted by 64tux
so if i have 2 inches of free play, thats to much???
That's too much if your clutch isn't releasing. It must be picking up right on the floor. Can you get it into reverse without it grinding?