Mike_964

After 20 minutes on the track there where traces of oil on my rear wheel, see picture below.
The oil came out of the small hole in the middle of the drive shaft.
I assume that there is a worn seal at the CV joint that couldn't handle the high temperature when driving on the track and I wan't to change it, but I'm not sure how to change the seal.
I can't really see the seal either in PET or the repair manual.
I'm also not sure how to remove the drive axle, is it nesessary to remove the axle from the transmission.
Any advice will be welcome.

chancecasey

WOW!

I just replaced both of my shafts a few weeks ago - Don't remember anything on the outboard C.V. joint that could leak like that unless you've torn the boot - I'm sure someone else can chime in who has better knowledge of what to do next. Maybe something wrong with the hub. Get the shaft out for further inspection.

What I do know:

The shafts are about $300 each new. If the outboard C.V. joint (as in bearings/races, not seals) is bad, you have to replace the whole shaft. You have to take an impact wrench or really long breaker bar, and soak the crap out of that nut on the outside, to pop it off. Then you have to remove the 6 hex bolts where the shaft connects to tranny, then the whole thing slides inward from the wheel hub.

Good luck!

tafkai

looks like you thoroughly warmed the cv grease !!!

i'd re-pack the wheel bearing , then check the cv boot for splits\cracks .
if its ok , refill with a little cv greasde , then renew the metal cable ties that seal the boot .

if you gotta replace the full boot , dont bother with the "split and glue" cv boot kits .
imho , theyre a temporary fix until you can get the car to someone who can do the job properly !!

Mike_964

Thanks for your advice.
I managede to remove the drive shaft, yes the nut on the outside, was tightened as it was never supposed to be removed....
The boot has no cracks and the leak is not because of the boot.
The hole in the drive shaft goes all the way up to the joint itself, and has as far as I can tell no seal.
The joint itself looks and feels allright, so to be honest I think, I made a big deal out of nothing.
The grease has a consistency like oil and not grease, perhaps thats the problem.
I spun the car around a couple of times on the track, perhaps that pushed some of the oil out into the hole and then the high temperature got it to flow all the way out.
Anyone got a better idea of what went wrong?

Red rooster

Just checked my rear drive shaft ends. No hole going all the way through !! Looks like you may have lost a seal ?

All the best

Geoff

NineMeister

The 964RS, 993RS, GT2 and Cup cars have a hollow stub axle on the outer joint to allow air movement due to the heat build up in the brake/hub assembly that warms the joint through the wheelbearing, without it the pressure would/could blow the rubber boot in half. Looks like your car is either an RS or has had RS shafts fitted.

I usually get a trace of grease on the inside of my rear wheel after a track session, never the ammount that you have on your wheel but as you say this was probably due to your spin(s), so my advice is to simply refit everything with fresh grease and carry on regardless!

tonytaylor

Mine used to do that. Eventual diagnosis was the driveshafts were worn because when they were dismantled they were er... worn. Replaced one and had one refurnbished and it hasn't happened since.

Whether the driveshafts became worn because all the grease kept leaking out or the grease was leaking because the driveshaft was worn I've no idea.

Mike_964

Thanks a lot for your input.
I just tried inserting a 35 cm strip on the other drive shaft and it also got a small amount of grease on it.
My car is not an RS just a C2. But it was delivered with the M30 sport option, maybe that also means that the drive shafts are different. It had only done 56 000 miles (90 000 km) when I got it, so I doubt that they have been replaced.
It doesn't feel worn a all, so I think I will refit it an see what happens.

But at least it was a pain to remove the drive shaft out on the public parking lot

kurquhart

I had the exact same problem this past weekend with my 90 C2 (w/o M030) at the track (also w/ two spins). I haven't yet had time to tear into it, so I will be curious as to the final outcome.

Mike_964

I have decided to assemble it again, and see if it happens again.
The CV joint looks and feels like new so I think it just all the spinning around while the temperature is high. The fact that it also happened to Kris just make me more sure that it was just a coincidence.
I ordere a new locknut, some clips for the boot and some Optimoly HT, but since Porshce wanted $50 for 100g of CV grease I choose to find that another place
What brand of high temperature CV grease do you other guys use?

NineMeister

You should fit a new self-locking nut to the axle once you refit it, but my recommendation is to fit the twin nuts from a 993RS, the second nut being a locknut to ensure that the shaft does not come loose on track. Interestingly when I bought my car it did not have the locknuts and the driveshafts did come loose without them, which is how I found out the hard way.

chris walrod

I would venture to say this grease was from your wheel bearing rather than the outboard CV joint. May want to have a close look at it before reassembly.

NineMeister

If the grease was escaping from the wheelbearing it would come out behind the hub, not in front of it. In this case it is definitely coming though the axle centre vent hole.

Mike_964

There is no doubt that the grease comes from the axle centre vent hole.
At first when I saw the wheel I feared that it was from the wheel bearing, but after having looked closer it's definitely comming from the axle centre hole, I stuck in a screwdriver and it was smeared in the grease, which is not the case on the axle on the other side.
Hasn't anybody got some advice on which brand of grease to use?

kurquhart

My car was at the body shop for a while getting a FG hood fitted; just got it to the mechanic this week. They completely disassembled the RR axle and everything checked out just fine: CV, axles, bearings, locknut, etc. The concensus seems to be "wipe it off and keep driving".