Can a throwout bearing be serviced?

[gsxrken]

I had to perform a drop to replace my starter ring and go with a hi-torque mini starter.
My clutch still has 1/2 a life to it as measured with a caliper, so I'm not looking to add the $1200 or so for a turbo clutch replacement "just because". When my clutch does go, (hopefully not for another 20k or 5 years as I use the car sparingly) I'll just drop it again and go through it all at that time.
But as I looked at the throwout bearing, it appears that it looks dry and has a little play in it. I haven't held a new one in my hands so I don't know what to compare it to.
Should it have any noise or wiggle room at all? Are they serviceable with the right lube?

[chiplynch]

Hey, there is no way to service the bearing. It should be dry though. Unlike other cars, the Porsche 930 and most 911s use a "pulling bearing mechanism".. thus it does not push on the bearing but rather pulls on it. If you hear no noise when it spins in your hand, it should be good until your next clutch change. MOst folks would say, while you have it out to change out the whole clutch. Remember, it's not just the miles on the clutch parts, but the age itself.

Phillip

[hcoles]

do it all while you are in there unless you are fine with the time and effort to pull the engine/trans (you say you are fine with that) and having to do it when it may not be convenient. If you have needle bearings on the fork shaft, get those out of there IMO. For sure replace the TO bearing, it spins all the time. Remember to put a small amount of lube on the tube.

[scottb]

Originally Posted by hcoles

do it all while you are in there unless you are fine with the time and effort to pull the engine/trans (you say you are fine with that) and having to do it when it may not be convenient.

+1.

You already have it apart. A new TO bearing is less than $200. Why go through the headache and hassle of having to replace it at an inopportune time? With everything taken apart, now is the time to do it.

[gsxrken]

Thank you for the replies. It's not a matter of being cheap. I am also blessed with the facility and tools to easily drop the engine when I need to. I spend serious coin on this and my other cars... when it makes sense. I just placed a $950 "while-I'm-in-there" order with Wayne, LOL. But this clutch setup only has 30k on it (something I didn't mention, as I was looking for service ideas) and after 30 years of wrenching, I don't view the TO bearing as a consumable in the sense that the clutch cable is, which I did order.

[andyt11]

Mine was noisey and dry when I spun it and we replaced it. It's not so expensive that its worth the hassle of dropping again to do it later. The same for the clutch fork needle bearings.

But I'm with you on the clutch. Too much money to do just because you already have it apart.Especially if you have the facilities to do this kind of thing whenever you feel like it. It will take years to wear it out.

[hcoles]

to answer the question, I haven't heard of anyone getting the TO bearing apart or cleaning in some manner and repacking with grease, I can't remember what they feel like new.

[Walt Fricke]

I took apart a regular (not your turbo type) 915 TOB once. It didn't feel nice and loose and free spinning, so I got a replacement (not as expensive as the turbo part), and then opened it up. Disassembly was tricky to do, is what I remember. The parts I cleaned looked OK, and it would have been possible to relubricate it. Looked like the lubricating grease had dried out. But it looked even trickier to reassemble it, so it sits in a box in my old parts dungeon.

It has a fairly hard life. The part which is attached to the pressure plate diaphragm spring spins at engine speed all the time. The other part ought not to spin at all, just move back and forth as the clutch pedal is depressed and the spring pulled forward to release the clutch disk.

Which is why I think that tightness is a bad sign, but free spinning ought not to be.

[RoninLB]

I'm easy on the clutch but always change the TO bearing when engine/tranny has to come down

I keep the pilot bearing in good shape by starting the car with the clutch engaged so I don't change it without the whole clutch/flywheel package

[gsxrken]

So it turns out it can be done. Simple, actually. There is a snap ring and then two tin covers need to be gently pried off. Then there is a plastic ball separator that gets lifted up, make sure the balls and track are not scored, and then lightly lube with hi temp wheel bearing grease. Reassemble in reverse order.
I wouldn't claim that this should take the place of replacing the TO bearing as part of a clutch job, but in my case, I think it was a reasonable maintenance step to take.

[equality72521]

Just as gsxrken, I dismantled mine, cleaned, repacked with grease, and reassembled. That was several thousand miles ago with no problems.

[Walt Fricke]

Bravo

[hcoles]

excellent, do you take the balls out or just clean with brake cleaner and repack?
At this point the only question might be what lube is the very best, if too much lube is used will it get on the clutch or fling out somewhere else?

[equality72521]

I just cleaned and used a light fill of moly

[Walt Fricke]

I don't think lube escaping from a TOB is likely to cause a clutch problem. As is the case with a leak at the rear main seal (on pre-water cooled 911s, anyway), the lubricant travels radially, and there is little which will tend to move it rearward toward the far side of the pressure plate where it could do some mischief.

And it would be hard to overlube it, as the space is very small, unlike CVs or front wheel bearings, where you could pack in a lot more than is needed.

[gsxrken]

Mark- why moly if I can ask. I have some and could redo it if makes sense to do so. My thinking was it was essentially a ball bearing, and bearing grease in my mind was always the usual stuff.
Curious b/c the lube was blackish in color and I didn't guess that it maybe was moly.

[hcoles]

Originally Posted by gsxrken

Mark- why moly if I can ask. I have some and could redo it if makes sense to do so. My thinking was it was essentially a ball bearing, and bearing grease in my mind was always the usual stuff.
Curious b/c the lube was blackish in color and I didn't guess that it maybe was moly.

+1 on technical discussion re. lubes to use for this application. I assume there is more to finding the best lube than a default of wheel bearing grease. Could be it is the best in this case, just curious. For example the lube used in fans is an involved science.

[tobluforu]

Originally Posted by RoninLB

I'm easy on the clutch but always change the TO bearing when engine/tranny has to come down

I keep the pilot bearing in good shape by starting the car with the clutch engaged so I don't change it without the whole clutch/flywheel package

Sorry for the knuckle-head question, but can you explain how starting the car with the clutch engaged keeps the Pilot in good shape? Thanks

[matt930s]

Originally Posted by tobluforu

Sorry for the knuckle-head question, but can you explain how starting the car with the clutch engaged keeps the Pilot in good shape? Thanks

I was thinking the same thing?

[hcoles]

Originally Posted by matt930s

I was thinking the same thing?

me too, I've heard of and done, disengage the clutch to assist with starting so the trans doesn't have to be turned, but not to be easy on the TO bearing.