Premature Release (Throwout) Bearing Failure

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dtrumbo
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Premature Release (Throwout) Bearing Failure

Post by dtrumbo » Mon May 09, 2011 6:51 am

Hi all,

Almost three years ago I had the transmission in my wife's '70 transporter rebuilt. At the time, because I was in there and it seemed the right thing to do, I replaced the release bearing with a brand new German-made bearing I bought from Wolfsburg West. Fast-forward to 2011 and earlier this year I noticed a lovely growling noise when the clutch pedal is pushed in. I also noticed it was getting progressively difficult to shift the bus into first gear while sitting at a stop. I realized that the clutch needed adjusting and performed the required maintenance (shame on me not having done it sooner). Now the transaxle shifts as it should, but the growling noise is still present and I'm certain not going to go away on its own.

My question. Can a mis-adjusted clutch cause a premature failure of the release bearing or is the German-made, premium-priced bearing going on the list of "belatedly discovered junk"?
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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sped372
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Re: Premature Release (Throwout) Bearing Failure

Post by sped372 » Mon May 09, 2011 7:00 am

dtrumbo wrote:is the German-made, premium-priced bearing going on the list of "belatedly discovered junk"?
God I hope not, I just put one of those in last year.
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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Amskeptic
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Re: Premature Release (Throwout) Bearing Failure

Post by Amskeptic » Mon May 09, 2011 5:43 pm

dtrumbo wrote:Hi all,

Almost three years ago I had the transmission in my wife's '70 transporter rebuilt. At the time, because I was in there and it seemed the right thing to do, I replaced the release bearing with a brand new German-made bearing I bought from Wolfsburg West. Fast-forward to 2011 and earlier this year I noticed a lovely growling noise when the clutch pedal is pushed in. I also noticed it was getting progressively difficult to shift the bus into first gear while sitting at a stop. I realized that the clutch needed adjusting and performed the required maintenance (shame on me not having done it sooner). Now the transaxle shifts as it should, but the growling noise is still present and I'm certain not going to go away on its own.

My question. Can a mis-adjusted clutch cause a premature failure of the release bearing or is the German-made, premium-priced bearing going on the list of "belatedly discovered junk"?
If this release bearing rides on a collar on the input shaft, then bad bearing may be the answer. But if you have the earlier bell housing where the release bearing floats and has to hit the collar on the pressure plate, you may have a non-concentricity issue. It will be apparent when you remove the engine, because there will be unusual shine on both the pressure plate collar and the release bearing contact surface. Many late style finger/diaphragm pressure plates used on early style transaxles (that originally had the old three arm pressure plates) come with these collars slapped on to the fingers and they do not run true. Perhaps the only distinguishing symptom between a bad bearing and a non-concentricity is that the bad bearing needs a little pressure on the pedal to get noisy while the non-concentricity will make its noise with very little contact pressure. If you suddenly had hard shifting one fine day, and your adjustment tamed it, perhaps you have a partial failure of the cross shaft/clutch fork arms that could definitely ruin concentricity, make the clutch not release until you compensated with an adjustment . . . mebbee.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,155 miles
Chloe - 1970 bus . . . . . . . . . . . 206,820 miles
Naranja - 1977 Westfalia . . . . . 98,380 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 78,885 miles

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dtrumbo
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Re: Premature Release (Throwout) Bearing Failure

Post by dtrumbo » Tue May 10, 2011 6:34 am

I follow ya... the noise is there only with full pedal pressure.

These pictures from the engine/transaxle pull when the release bearing was replaced as a precaution three years ago.
Image
Image

If I think I know what I'm seeing, this is the three-arm clutch with no collar and thusly the release bearing floats.

I do get the possibility of a cross-shaft failure which could cause the issue. Now all I need is time to pull the motor and take a look-see.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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Re: Premature Release (Throwout) Bearing Failure

Post by Amskeptic » Wed May 11, 2011 4:57 am

dtrumbo wrote:I follow ya... the noise is there only with full pedal pressure.
Now all I need is time to pull the motor and take a look-see.
We await with bated breath.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,155 miles
Chloe - 1970 bus . . . . . . . . . . . 206,820 miles
Naranja - 1977 Westfalia . . . . . 98,380 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 78,885 miles

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dtrumbo
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Re: Premature Release (Throwout) Bearing Failure

Post by dtrumbo » Sun May 06, 2012 7:34 am

Amskeptic wrote:We await with bated breath.
Colin
You shall await no longer...

So Colin, when exactly did you visit my my garage bespectacaled with your x-ray goggles? Absolutely everything you said turned out to be the case.

I submit for your approval a mini photo essay.

Image
Ewww!

Image
Again, ewww!

Image
See the uneven wear on the throwout bearing? Even harder to see is the spiral engravings on the face of the bearing. It looks sorta like the VW/Audi logo or like something you made with your Spirograph as a kid (If you're not old enough to know what a Spirograph is, go screw yourself! Just kidding.).

Image
More irregular wear patterns on the pressure plate.

Image
Yes, the flywheel had been subjected to some slipping/heat probably due to the leaky seal which was replaced during this little odd-yssey.

Now to the root cause of all of this. As the evidence presented has shown, the throwout bearing and the pressure plate weren't pushing against each other evenly. This means the bearing and the plate weren't in the same 'astral plane' with each other. Well, here's the reason.

Image
This is the cross shaft/clutch fork Colin mentioned. Notice the difference in dimension of the half-moon cutout to the little hole for the bearing retaining clip. The side closest to you in the picture has worn nearly to the point of complete failure while the other side still has some meat to it. Given this, the right (passenger) side of the bearing was farther away from the pressure plate than the left (driver) side creating our uneven wear problem.

Image
This didn't help. As you can see the polyurethane bushing is cracked and in all other ways shot.

I could go off on a completely separate rant about aftermarket parts, but in the interest of time I'll restrain myself. I purchased a new cross shaft and bushing kit. The new bushing would not fit on the new cross shaft. I assumed by looking at the shoddy construction of the new cross shaft that it was likely the part not manufactured correctly. I then bought a good used genuine VW cross shaft from my good friend Ken Madson at The Bus Company (http://www.thebusco.com) only to find that my brand new aftermarket bushing won't fit on this shaft either. I then borrow a bushing reamer from my co-worker and ream the new bushing so it fits ever so nicely on both of my new cross shafts. If you were curious, the previous owner ground down the cross shaft to fit in the POS polyurethane bushing. There are always a couple of ways to fry the fish.

Now it's time for reassembly.

Image
Mmmm! Shiny!

Image
New-style pressure plate.

Image
This is how poorly made/out of balance Brazilian Sachs pressure plates are made today. Again... must... show... restraint.

Image
Image

With all these new and shiny parts, it shifts like butter!
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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ruckman101
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Re: Premature Release (Throwout) Bearing Failure

Post by ruckman101 » Sun May 06, 2012 9:45 am

Glad I took back the polyurethane bushing. Good call Colin! I couldn't get the better one into the transmission case. It fit the arm just fine. Had to sand down the outside of the bushing.


neal
The slipper has no teeth.

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Gypsie
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Re: Premature Release (Throwout) Bearing Failure

Post by Gypsie » Mon May 07, 2012 12:33 pm

dtrumbo wrote:With all these new and shiny parts, it shifts like butter!
I prefer vaseline. But you knew that.

Oh crap Tech forum....

uh, what about torque spec?.....

whew, that was close.


Nice follow through. I can now unbate my breath....
So it all started when I wanted to get better gas mileage....

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dtrumbo
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Re: Premature Release (Throwout) Bearing Failure

Post by dtrumbo » Mon May 07, 2012 1:26 pm

Gypsie wrote:uh, what about torque spec?.....
To help you keep yourself out of trouble... For removing the old and installing the new gland nut I bought this (not so) little beauty at (where else) Harbor Freight Tools.

Image

At a little over 33" in length it made getting the old nut off a breeze and allowed me to properly torque (+-4% which is the same spec for a Snap-On capable of 253 foot/pounds) the new nut. It even comes in its own nice blow-molded case and cost only $79.00 plus I had a 20% off coupon. Snap-On's website sells theirs for $750.00. I couldn't quite justify the difference.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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ruckman101
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Re: Premature Release (Throwout) Bearing Failure

Post by ruckman101 » Mon May 07, 2012 1:43 pm

I have one of those for the back axle nuts. I use a torq converter on the gland nut.

Image


neal
The slipper has no teeth.

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Amskeptic
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Re: Premature Release (Throwout) Bearing Failure

Post by Amskeptic » Mon May 07, 2012 4:07 pm

dtrumbo wrote:
Amskeptic wrote:We await with bated breath.
Colin
You shall await no longer...

So Colin, when exactly did you visit my my garage bespectacaled with your x-ray goggles?
Well Dick, you have reached poptoptom's exalted state of time warp, I see.

I just apply for a premonitory tele-optical transmission permit and check out the offset on on your clutch lever from my own trance station here at the drawing board. Was there any evidence of grease on the cross fork/release bearing contact surface? It looks like you had a newish cross fork made out of Chinese metal-substitute.
Colin :colors:
BobD - 1978 Bus . . . . . . . . . . .111,155 miles
Chloe - 1970 bus . . . . . . . . . . . 206,820 miles
Naranja - 1977 Westfalia . . . . . 98,380 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 78,885 miles

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dtrumbo
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Re: Premature Release (Throwout) Bearing Failure

Post by dtrumbo » Mon May 07, 2012 5:34 pm

Amskeptic wrote:Was there any evidence of grease on the cross fork/release bearing contact surface? It looks like you had a newish cross fork made out of Chinese metal-substitute.
Colin :colors:
Of course there was no grease because I wasn't smart enough to put any on there when I replaced the bearing a few years back. Lesson learned, now there is a little dab of grease. Not enough to get flung off and contaminate the clutch disk. The worn out cross shaft was the yellowish Chinese synthetic metal as was the aftermarket replacement that I bought. That's why I ended up installing the Jenn-you-whine VW shaft I got from Ken.

Yes, I complained to AutohausAZ about the qwality of the aftermarket part. I even explained that it wasn't economically worth returning to them as the postage and hassle more than equaled the original purchase price. I asked for a simple credit to my credit card or even "store credit" on my account. The representative told me to submit the online RMA request and to explain my concern about return shipping, etc. I received the boilerplate reply granting my RMA but not offering any consideration for return shipping or the above mentioned request for credit. Needless to say, I still have it and will hang on to it in case my Jenn-you-whine VW shaft breaks. You may now all start holding your collective breaths!
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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dtrumbo
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Re: Premature Release (Throwout) Bearing Failure

Post by dtrumbo » Mon May 07, 2012 5:36 pm

ruckman101 wrote:Image
I tried to buy one of those, but I could not find one locally... and I was in a hurry.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

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ruckman101
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Re: Premature Release (Throwout) Bearing Failure

Post by ruckman101 » Mon May 07, 2012 6:05 pm

I may have found the only one in town. It's sure nice to torque that gland nut to spec with my normal little ol' 3/8 inch socket handle.


neal
The slipper has no teeth.

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