924Board.org

Brando · Joined: 11 Aug 2004 Posts: 14 Location: Riverside, CA

Hi there, I'm new around here.

Currently i have a '78 924 with an Audi motor and Audi 4-speed transmission. When i first got this car it had electrical problems galore, which are solved. I was able to drive the car for about a month before something horrible happened. On my way back from Palm Springs, the pilot bearing and driveshaft died. So, not being sure what happened i had the car taken to a German Car specialist and they replaced the driveshaft and pilot bearing for about $1300. The day after i had to go back because my catalytic converter had come loose (bolts backed out) and almost disassembled on the freeway. They replaced the bolts and it was all dandy. About a week after i began to notice horrible shuddering when taking off in first, and a very very bad grinding noise when i'd press the clutch pedal in. I took the car back again, drove it for the mechanic, the mechanic drove the car and told me afterwards that my release/throwout bearing was bad.

I was very cautious in my driving until i could afford a clutch kit (have one now). I drove the car and on my way home from work about 2 weeks ago there was tremendous shuddering throughout the car in all RPM ranges. I was nearly home then stalled trying to move in 1st from a signal. Eventually i was able to start the car and it wouldn't get into gear without alot of effort. The grinding noise was now present while the car idled or revving in neutral, so i feared the driveshaft was damaged, again.

After i had the car towed home this past weekend i took things apart to inspect and replace the clutch assembly (just acquired a sachs clutch kit last friday) and my pilot bearing and driveshaft are toast again. Of course, examining all of the old clutch equipment... It's all in good shape! Release/throwout bearing is not damaged, friction plate is fine, clutch disc is a bit worn but also fine...

So now after you know my story... I'm starting to wonder, what would have caused the second driveshaft and pilot bearing to die? Everything was re-assembled to spec by the mechanic (as far as i know) and it functioned perfectly fine for a week then began to fail... Could it have been a misalignment between the transmission and engine? Heat? Water? I'm at a loss here, and unfortunately am currently parting the car out, but i'm still pressed to know whatt would cause driveshaft failure in a 924. As far as i know, this is a very, very rare occurrance. The only other driveshaft failure reference i know of is with early 928s and auto transmissions... too much forward and backwards play on the bearing... but would that apply to a 924?

Thanks in advance... I'm clueless...

Lizard · Posted: Sat Aug 14, 2004 6:41 am Post subject:

well the cause of your driveshaft failure I would suspect being a missing support bearing in the end of the crank, what should happen is in the end of the crank there should be a small bearing which the end of the TT shaft "clicks" into and this supports it and decreases the end wiggling around, also I would suspect that the first bearing was probably pushed too far into the shaft, what you could do is to remove the tranny (VERY EASY) and then remove the torque tube again very easy and once removed read the Tech section on rebuilding the torque tube, if you are worried about the bearings failing again then I would install 4 bearings into the shaft and space them out abit more and have onse closer to the end of the tube itself, this will strengthen it up and prevent failure further, at the same time I would recommend that you install the breaing into the end of the crank for the end of the shaft to "click" into

once more I ask for you NOT to part out the car, if you wish to get rid of it sell it as a whole, or ask for our assistance on the board and do the work yourself on the side.
_________________
3 928s,

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

Lizard, the pilot bearing is the same as what you describe as the bearing that the spline clicks into.

Brando- What made you determine the pilot bearing and torque tube were dead the first time? I had a TT chew up a pilot bearing once. The reason was that the TT support bearing that is closest to the engine worked its way backward allowing the shaft to not be secured well enough in the front. The wobbling eventually destroyed the pilot bearing.

Do you know the story on the TT that your shop originally replaced? They may have just replaced the pilot bearing. This would make sense why it happened again- the TT bearing is still in the wrong place. I would be surprised if they checked the spec for the TT bearing placement before they just slapped in a new pilot bearing.

-nick

Lizard · Posted: Sat Aug 14, 2004 7:15 am Post subject:

thanx nick I could remember the name of it.
_________________
3 928s,

Brando · Joined: 11 Aug 2004 Posts: 14 Location: Riverside, CA

Thanks guys i apprecieate the replies!

To clarify, the bearing i'm speaking of is the pilot bearing, which is seated into the flywheel on the backside of the engine.

-nick:
I found out the first time because i had lost all power when trying to ease the clutch in. I had thought that maybe my clutch cable had stretched but once i took the steps to adjust the clutch cable (manually moving the release bearing forward) a few of the pilot bearing rollers fell into my face. I did get to see the old driveshaft compared to the new one. I had it sent to the mechanic's shop and i saw the tip of my old driveshaft... large, large chunks missing out of the middle of the smooth part.

I see lizard insists i keep the car and fix it. the problem being i am poor and do not have the pocket change to continually invest into a 924 that needs a full restoration. It's better to pass this on as a project car and save for a reliable econo box. I very much hope that i can find someone who'll take it on and pay me more than $500 for it... but that's some pretty slim chances i'll get more than what i paid for it non-running back in February.

Lizard · Posted: Sat Aug 14, 2004 4:36 pm Post subject:

I am not really insisting that you keep it and fix it, I am more concerned that you not part out a decent car, sell it whole and let someone have an entire car that they dont have to scavange alot of parts for,

in regards to the parts and cost, as I said we will be able to give you all the info you need and I am sure that alot of people here on the board have good parts that they would let go fairly cheap (I know I have on a few occasions). and you could even put the car aside for a month or 2 unitl you have enough money and have it as a backup
_________________
3 928s,