Clutch release bearing and Guide sleeve clearance?

[Katz Tsubai]

I have a question for those who have replaced the clutch release bearing (aka throwout bearing) on E30s.  I have searched this site and a couple others with no luck.

I'm in the process of replacing mine, and I noticed that the new bearing is very loose on the input shaft guide on tranny.  The radial clearance is about 1/8".  Is this normal for these cars?  All other cars I've worked on had smooth clearance fit, but certainly not 1/8".

I thought I received the wrong part, but as far as I can tell, it is the correct part for the car.  It's a common replacement part for E30, E36, etc. manufactured by Sachs.  The part# is 3151 231 031.  Inside Diameter measures 1.515", which is 0.010" larger than worn-out OE piece.

Judging from the wear pattern, I don't think the input sleeve isn't worn much.  Besides, I don't think it's possible to wear 1/8" off of hardened steel.

Has there been some update on the input sleeve, and that I'm supposed to replace it along with the bearing?  Porsche has done that on some model.

I would like to know how your bearing fit when you replaced it.  If yours were indeed as loose-fit as mine is, have you experienced any subsequent problem?  The clutch pedal on my car had been very stiff compared to my other E30, and I'm guessing this could have been a part of the problem.  

Thanks much in advance!!

[Katz Tsubai]

Actually, never mind.  I know this isn't right, even if this was normal to these cars.  

There's a great possibility that the release bearing comes in contact to the pressure plate fingers eccentrically.  It will probably makes itself concentric after a few revolutions, but that few revolusions, each time I step on the clutch pedal, will probably beat up the bearing.  And I don't need another release bearing fail on me 150 miles from home.

I have to fix the car today, so I'll just make a sleeve that takes up the excessive clearance.

Thanks for looking.

[bmwman91]

That is a little odd.  Could they have shipped the wrong part?  Although I am running an E21 323i TOB for my M20 flywheel setup, it sat tighter on the input shaft than you said your replacement was.  I suppose if you are able to turn out a sleeve to eat the slack then the problem is probably solved.

BTW...you don't happen to work at Cisco Systems do you?

[FL318is]

I will be watching this thread.  Sometimes mine has a cyclic noise when engaging 1st gear.

[Katz Tsubai]

Sorry, I have to make a correction.  The release bearing I used was indeed a different part.

What happened was, I bought a replacement through IMC (or something like that) when the bearing went south.  I pulled the transmission out, and found out that it took out a couple of diaghram fingers with it.

Since I needed to replace a pressure plate and I really didn't have an inclination to take the tranny out twice, I decided to get a light flywheel/clutch kit from Metric Mechanic.

At this point, I did try the replacement bearing.  It felt loose (about 0.025" radial clearance), but I didn't measure it.

The flywheel/clutch kit arrived, with another release bearing.  Although they looked identical, I decided to use the one included in the kit, thinking that there may be some difference that is not apparent.

Turned out, they were different indeed.  This one had larger bore size.  It had about 0.100" clearance, so my estimate of 1/8" was pretty close.

So that's what happened.  I apologize for the confusion.


Anyway, 0.025" clearance on the replacement bearing was still a bit more than I liked, especially with the new pressure plate that has larger center "hole" that is defined by the tips of diaghram fingers.  There isn't much contact area between the bearing and the fingers (though the area does increase as the clutch pedal is depressed).
 
So I ended up using the big-bore bearing, and made a sleeve from 1.625" x 0.134" HREW round tube I had laying around.  Clearance now is 0.006", which I feel much more comfortable.

Car is running now, and I can honestly say that I recommend light flywheel for these cars.  People at Metric Mechanic was very pleasant to deal with.  I will send them an e-mail to thank them for their superior service, as well as to raise my concern about the bearing clearance.

P.S.  I don't work for Cisco.

[nickmpower]

yeah my 323 bearing seems loose on my shaft also, though my stock one isnt that loose. I may get a stock bearing then weld on some extentions to it to increase the height were it contacts the tob arm