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throw-out bearing noise

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MadRiver

MadRiver

Jedi Knight
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Howdy all. I've started to notice that before my 250 warms up, the throw-out bearing is making the typical nasty whining sound they make when they're wearing out. If I put the smallest bit of pressure on the clutch, it stops. It also seems to stop once the old boy is warmed up. Now, I'd say that it's time to change the bearing, but I had a new clutch and bearing put in when the 250 got a new tranny less than 1000 miles ago. Thoughts from the collective?

Thanks!
 
This is, unfortunately, a common problem. What is happening is that the slight pressure kept against the TOB by the spring inside the clutch slave cylinder, is not enough to keep the bearing turning when your foot is not on the clutch. It doesn't necessarily mean the bearing is failing (although it might).

In a nutshell, the original bearings were a special "easy turning" design. But some replacements, both those sold as "upgrades" and some sold as exact replacements, don't turn as easily.

My suggestion is to first check that the spring inside the slave cylinder is in good shape (they do sometimes break). If so, you can try adding another external spring to supply a bit more force. If that doesn't work, then you likely do have a bearing that is going bad.

Don't just ignore it, since that noise you hear is the TOB ruining the pressure plate. Eventually the PP will fail as well.
 
Bugger! I mean thanks guys! :eek:)

Another project for the winter.
 
just curious,what type/brand of T/O bearing have you got in there?
 
I am curious is the whining noise cause by the Throw out bearing comming in contact with the clutch fingers but the bearing is not spinning so its basically gringing away at the metal??
 
I believe so, yes. Here's a photo Nelson Riedel took of the damage, plus a photo of Joachim Gunst's solution installed (which I should have posted before instead of the drawings).
 
And here is the results of Mr. Gunst's setup (actually the second installation since the first was worse) after one year or 1,300 miles. Unbelievable squeal and lousy feel to the clutch on not one, but two different bearings and B&B clutch packages.

These were installed in a "textbook" manner to his instructions with the guides, the return spring and all new cross shafts parts.

They MAY only work on the Luk or Sachs PP, but NEVER with the Borg & Beck, which was and possibly may still be advertised in TRF's catalog.

https://www.74tr6.com/clutchreplacement.htm
 
I don't think Bill said that he had the Gunst. At any rate the clutch system is a big weakness for some reason on these cars. Mostly I think because of the quality of replacement parts (and supporting hydraulic systems).

I've heard many horror stories about the B&B clutch and wouldn't touch one with a 29-1/2 foot pole. If I were building an "OEMish" clutch system today, I'd opt for the Sachs and Koyo T/O (aka TRF Magic clutch). If I were going the Gunst route, I'd only go with the LUK clutch, since that's the brand that Gunst recommends.

If you do end up replacing anything, just make sure all the bushings in the gearbox are good for the clutch lever, along acceptable play in the clutch pedal itself, and not to mention good hydraulics. All these things can result in some strange clutch behavior if they're worn.

Or you can do what I did; trash all of it and go 100% Hydraulic throwout bearing. Good stuff.
 
LastDeadLast said:
Or you can do what I did; trash all of it and go 100% Hydraulic throwout bearing. Good stuff.
Click to expand...

Shannon:

You have probably detailed your TOB conversion elsewhere, but could you say a little more about it here? Was it a kit or something you fabricated? Thanks.

Matt
 
OK now I am really concerned about replacing a clutch with a new one, especially after reading that 17 page report listed in one of the posts, I dont see that any one of these after market pressure plates is really the correct unit. is there any other alternative, I definately dont want the B and B unit, the one used for a saab looks questionable. Is any one using one of the coaxial clutch slave cylinders and T.O. Bearing that bolts inside the bell housing, which does away with the cross shaft assembly and where did you get it? I dont recall having any of these problems replacing clutches in my old volvos
 
HVDA sells the hydraulic TOB separately (as well as part of the 5 speed conversion).

HVDA
Herman van den Akker
P.O. Box 6812
Pine Mountain Club, CA 93222-6812
Phone: (661) 242-1253
E-Mail: handhvan@msn.com

Not my cup o'tea (IMO the original setup wasn't broken), but everyone I know that has one just loves it.

Shannon, I realize Bill didn't say he had the Gunst bearing. But as I said, the particular problem is common to a lot of bearings (including some that were mistakenly sold as OEM replacements) and I feel Joachim's solution to that particular problem is a valid one.

Certainly there are other valid solutions, including tearing it all back apart and using Herman's (expensive) co-axial slave unit.

But after driving literally hundreds of thousands of miles with a B&B clutch, much of it in stop-n-go Los Angeles area traffic; I simply don't believe there is anything substantially wrong with B&B clutches as a group. IMO Brent Kiser's explanation of the <u>wrong</u> clutch being sold for the TR6 (which I've heard from other sources as well) makes far more sense to me.

Edit : After all, if you can't believe a Mechanical Engineer from Purdue, who can you believe ?
/bcforum/images/%%GRAEMLIN_URL%%/grin.gif

Randall - Purdue Alumni
 
Howdy all -- Can't say that I recall the clutch and bearing used by the shop that did the tranny swap last year. However, I've never really torn town the clutch hydraulics since owning the car, and it's probably the only system I haven't personally inspected. So, I'll probably start with examining the slave cylinder spring, and then go from there.

I appreciate everyone's advice!
 
Randall,

Don't get me wrong, I think if properly setup, the original clutch configuration is a nice piece that can provide hours of fun for the entire family! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

In my case, I already had the gearbox out to replace the clutch, plus I was overhauling all the supporting systems (hydraulics, linkages, shafts, etc). Once the replacement cost for all that stuff is brought into the picture, the HVDA starts to make a little more sense. Plus, I'm a sucker for these types of upgrades; Hidden high-tech I suppose.

All this from a Computer Science/Finance guy from Virginia Tech.
 
Howdy gang:

Well, I got the new slave cylinder in this weekend. Painless operation. The spring on the old slave cylinder was indeed very weak. When I had it out, I did a test by pushing the cylinder into the bore, and seeing how well the spring pushed it back. It kept getting stuck in the bore, in sharp contrast to the new one. Easily installed the new one, and bled the system quickly.

Now for the bad part. I'm still getting the nasty sound of the throw-out bearing spinning on the pressure plate. It's certainly not as bad, but still there, and I still get a loud chirp when changing gears.

I can't recall the TOB in the car -- my garage was under construction, and in a moment of bad judgment, I had a local garage that purportedly specializes in English cars do the work.

Should my next step be the set-up described by Randall? Has anyone had any issues or problems with that setup? Seems easy enough to fabricate.

Thanks as always!
 
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