Throw Out Bearing going bad?
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,113
Likes: 35
From: LaUgH, mOrE!
Throw Out Bearing going bad?
How do you know when your throw out bearing is going bad? When I press the clutch ('79, L82 4 speed) slightly you can hear the bearing engage with a whirring noise. The noise stays with the pedal all the way down to the floor. You can feel a light vibration in your foot and hear the whirring with your foot to the floor. It's not a whine sound, though.
... or is this normal?
I'm sure the bearing is original. The car has 11,500 miles on it. However, the clutch is solid every time it engages.
Any thoughts? Thanks.
... or is this normal?
I'm sure the bearing is original. The car has 11,500 miles on it. However, the clutch is solid every time it engages.
Any thoughts? Thanks.
Pro
Joined: Oct 2006
Posts: 675
Likes: 0
From: Stafford, VA
sounds like you are going to need to replace that sooner instead of later
when they make noise and vibrate they will last a little while
beware of damage to other things it may cause if you dont replace
k
when they make noise and vibrate they will last a little while
beware of damage to other things it may cause if you dont replace
k
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Don't worry about it till it blowed up real good, not to say don't take care of it before it blow, if it's a throwout bearing going south it will get worse and worse but still not a major repair 
Last edited by MotorHead; Aug 15, 2010 at 09:53 PM.
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,113
Likes: 35
From: LaUgH, mOrE!
Thanks, all.
That's what I was thinking... replace it sooner rather than later. I guess that means an entire clutch kit since it is a pain to pull out the tranny & clutch anyway? (while I'm in there)
That's what I was thinking... replace it sooner rather than later. I guess that means an entire clutch kit since it is a pain to pull out the tranny & clutch anyway? (while I'm in there)
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Can you vouch for the 11k miles and how the car was driven?
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Racer
Joined: May 2001
Posts: 401
Likes: 0
From: Carlsbad CA
Not to hijack the thread (okay maybe a little) but if I undertstand this correctly, clutch noise that picks up when you depress the clutch is caused by the throwout bearing? What causes clutch noise when the clutch is out and the car is in neutral? Thanks.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
How do you know when your throw out bearing is going bad? When I press the clutch ('79, L82 4 speed) slightly you can hear the bearing engage with a whirring noise. The noise stays with the pedal all the way down to the floor. You can feel a light vibration in your foot and hear the whirring with your foot to the floor. It's not a whine sound, though.
... or is this normal?
I'm sure the bearing is original. The car has 11,500 miles on it. However, the clutch is solid every time it engages.
Any thoughts? Thanks.
... or is this normal?
I'm sure the bearing is original. The car has 11,500 miles on it. However, the clutch is solid every time it engages.
Any thoughts? Thanks.
The typical problem of a bad TO bearing is that if it is spinning and loses lubricant, the lube will contaminate the clutch disk and make it grabby and judder during start up.
If your clutch still operates normally, just ensure that the proper freeplay exists and check it every 10k miles or so because as the disk wears, the freeplay will become smaller until there isn't any - and that's bad for clutch life.
Last edited by larrywalk; Aug 17, 2010 at 02:18 PM.
Racer
Joined: Nov 2000
Posts: 290
Likes: 0
From: Omaha, NE
My 79 L-82, M21 T.O. bearing-not original- started to make a howl under those operational procedures in cold weather at around 70K miles. It would stop after a short warm up. I waited it out and it quit on it's own. Hasn't made a sound for at least 10 years. I vote to monitor and replace if it gets really bad-it is a lot of work and at 11k is barely broken in. Good luck.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If the bearing wore out that quickly, (1) it could have been a defective bearing; (2) the clutch pedal could have been adjusted improperly (not enough 'slack' in the pedal when not applied; or (3) you have a habit of "riding" the clutch pedal when driving, instead of fully releasing it.
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,113
Likes: 35
From: LaUgH, mOrE!
The throwout bearing should not be spinning or whirring when the clutch pedal is out; in fact, there should be approximately 1 1/4" of pedal travel before the TO bearing contacts the clutch pressure plate fingers which will cause it to start spinning when the engine is running.
The typical problem of a bad TO bearing is that if it is spinning and loses lubricant, the lube will contaminate the clutch disk and make it grabby and judder during start up.
If your clutch still operates normally, just ensure that the proper freeplay exists and check it every 10k miles or so because as the disk wears, the freeplay will become smaller until there isn't any - and that's bad for clutch life.
The typical problem of a bad TO bearing is that if it is spinning and loses lubricant, the lube will contaminate the clutch disk and make it grabby and judder during start up.
If your clutch still operates normally, just ensure that the proper freeplay exists and check it every 10k miles or so because as the disk wears, the freeplay will become smaller until there isn't any - and that's bad for clutch life.
I was thinking the TO bearing had lost its lube or dried out just sitting there most of its 31 year life (not being used). But maybe not?
larrywalk: There is no noise when the clutch pedal is out (clutch fully engaged). The clutch grabs solidly, consistently. The whirring (like a dry bearing sound) starts when you put your foot on the clutch pedal slightly and begin to depress it. I don't think it has a 1 1/4" of slack before the TO bearing begins to spin (and the whirring noise begins). More like 1/4".
7T1vette: Is that also what you mean by "not enough slack in the pedal when not applied?"
Does something need adjustment? If so, what/how do you adjust it?
Thank you.
Le Mans Master
Joined: Oct 2007
Posts: 7,455
Likes: 977
From: RI, Now Franklin/Nashville TN
My 78 L-82 4 speed has done that on and off for 27 years! Leave it alone or try the Wilcox adjustment above. I have never touched mine and have 65,000 miles on the clutch and engagement is perfect, just the whirring noise occassionally when hot. I had a couple of friends 20 years ago both with a 74 L-82 4 speed and another with a 79 L-82 4 speed bought new-both made the whirring noise when the clutch was engaged. Just monitor it and drive the car. Hope that helps!
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,113
Likes: 35
From: LaUgH, mOrE!
larrywalk: Very nice pic with the instructions. A couple of questions (I'm trying to understand how this works):
1. How do you apply the "5 pounds" of pressure?
2. Is the distance "X" what you are measuring to give you the 1 1/2 inch "free pedal travel"?
jb78L-82: Yes, those examples are very helpful! Thanks!
1. How do you apply the "5 pounds" of pressure?
2. Is the distance "X" what you are measuring to give you the 1 1/2 inch "free pedal travel"?
jb78L-82: Yes, those examples are very helpful! Thanks!
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Just push with your hand. You know about how much 5 pounds is (weight of a sack of sugar...oops! That dates me...they are 4 pounds now). Or, if you think in 'metric', a little more than 2 kilos. You just want to take the 'slack' out of the linkage and make contact with the T/O bearing.
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,113
Likes: 35
From: LaUgH, mOrE!
I finally got around to adjusting it. The X distance of .4 (.4"?) seemed like it put too much free pedal travel in the pedal and the clutch engaged right off the floor. So I reduced X to about 1/4" (before it was zero). This seems perfect.
No whirring noise when the pedal is pressed slightly (unlike before) in the free play range (about 1"). Clutch engages nicely at appropriate distance from the floor. I'll run with it.
This was a piece of cake to do from the area right below the brake fluid reservoir with a 9/16" long socket and 9/16" wrench. Thanks, everyone, for the fantastic inputs!
No whirring noise when the pedal is pressed slightly (unlike before) in the free play range (about 1"). Clutch engages nicely at appropriate distance from the floor. I'll run with it.
This was a piece of cake to do from the area right below the brake fluid reservoir with a 9/16" long socket and 9/16" wrench. Thanks, everyone, for the fantastic inputs!
