Eric_Oz_S2

I need some help diagnosing a problem.

I think it is the pilot bearing - but some advice would be great on others experience with pilot bearing failure.

At a recent track day I got this terrible vibration and sound like a very loud brzzzzzzz through the car and particularly through gear lever. It happened on a 3-2 downshift under brakes (revs not exactly matched as I haven't mastered heal and toe). I had also noticed a squealing sound immediately before, and when I left the pits earlier (for my 4th run) there was also a brief period of squealing. Furthermore, at this time there was a bit of a graunch when changing from 1st to 2nd.

When I got back to the pits I found the coolant elbow had popped out of the throttle body and I lost about a litre of coolant.

It didn't squeal again on the 200km trip back home, but I was taking it easy.

My theory is the coolant found its way into the clutch inspection opening and got to the pilot bearing. I went through the PO's service records and found when the clutch was replaced about 20,000 km ago the pilot bearing wasn;t replaced. Aghhh.

Can anyone confirm that the above symptoms would be the result of a pilot bearing failure?

944Ross

I can't imagine water could get past a flywheel and clutch spinning at 1,000's of RPM, and thru the seals on the pilot bearing, even if you stood there with a garden hose and squirted down the inspection hole. Your clutch would be slipping badly, if coolant was getting in there, and would likely be stuck together now.

Your pilot bearing could still be toast, tho.

KuHL 951

Usually when a pilot bearing fails it's from a leaky heater valve directly above the opening. Even then it takes awhile for the bearing to fail especially if the car sits too long. Yours sounds like the sealed bearing cage failed and flung all the lube out and the bearing failed. I doubt the coolant issue is related. Why anyone would not do a pilot bearing during a clutch job is beyond me...$7.90 worth of cheap insurance.

Mike C.

I agree with the above. One way you might get an idea if it is a bad PB is to put the car up on stands/ramps, gearbox in nuetral, use a piece of wood or have someone in there to hold down clutch pedal. Remove the driveshaft coupling access cover (a large, oddly shaped rubber plug) on the forward part of transaxle. Reach in there and grab the driveshaft coupling and rotate it (engine not running!). By disengaging the clutch and gearbox you can rotate the driveshaft this way and maybe get some feel for a rough or seized bearing on the other end.

944Ross

LOL! I would hope not!

Eric_Oz_S2

All good advice - thanks.

My other theory is that perhaps some degreaser found its way in there when I last cleaned the engine. I was careful not to spray near the openings, but who knows some may have found its way in.

Has anyone had this problem and confirmed the described as symptoms of a worn pilot bearing? I'm fairly confident this is the case, but it would be good to here others experience before I embark on this epic journey.

How long do pilot bearing normally last - my car has done 135000 km - about 80,000 miles.

Mike C.

I would expect a correctly installed pilot bearing to easily outlast a clutch disc. It doesn't have much load on it. My longest lasting clutch went 100,000 miles and the PB was fine. I replaced it anyway of course...

Eric_Oz_S2

Ok - did that. There is a slight noise from the last torque tube bearing when I spin the driveshaft by hand. It is a slight creaking sound, but there doesn't appear to be any resistance against it turning. Is this normal for a car of this age, and wouldn't they all do this?

With the engine on (idle), a can here a faint squeak from the clutch area - but that could just be the throw out bearing wobbling around.

I still think that it is the PB, coincidental or not with the coolant loss, as it is wort when the revs don't match (pilot bearing working its hardest).

Mike C.

It would seem the pilot is not that bad if you could rotate the driveshaft easily. A noisy torque tube bearing is also a possibility but it's hard for me to imagine an intermittent scenario for something like that. I re-read your original post and am thinking you may also want to check the gearbox lube for broken bits. I know it's frightening (to one's wallet) to think it could be the start of a ring & pinion disintegration or some other nasty tranny failure mode. What year car is it? The early series NA's are known for R&P failures although 80K miles would seem early for this (mine lasted 175K miles before grenading). I don't mean to wish you bad luck - even digging out a pilot bearing is better than digging into the tranny....

Eric_Oz_S2

I'll check the gearbox oil tonight. It is an 89 S2.

I have also noticed there is a bit of play in the left hand side driveshaft flange - both in and out (maybe 3mm) and side to side (maybe 1-2mm) - so would this be just the differential carrier bearing requiring replacement? It has been leaking oil for a while around the driveshafts, so I presume the bearing wobble contributes to failure of th oil seals. Would this be an easy job to replace considering the transaxle will be removed anyway?

Eric_Oz_S2

Ok - dropped the oil out of the trans - looks pretty clean, just some minute metallic specs in the oil.

Does anyone know what the maximum allowable float should be in the driveshaft flanges?

Mark944na86

Sorry to hear about your PB problems, Eric. Unfortunately, I've never worked on clutch/transmission on these cars before, so I can't offer anything in terms of advice or know-how. But if you need to borrow a tool, or need another pair of hands to help, just say!