Iwanna928

I have a 79 us spec. I have noticed lately that when the clutch pedal isn't depressed there is a slight noise. It disappears when pressed . The noise is consistant and not very loud. It sounds like it is coming from under the shifter,TT area. Sounds like something might be grabbing.

I am going to put in a short throw shifter and have the clutch fluid changed and bleed this weekend.

Any idea on the noise?

Thanks

Stephen

mark kibort

I had one of those noises, never figured it out where it came from but it went away with even the slightest clutch pedal pressure. probably throw out bearing.

Iwanna928

Thanks Mark.

Stephen

jpNcos

I rebuilt my clutch 2 years ago and have this same issue. I pulled the clutch out 3 times thinking I screwed something up but it necer went away and I never found anything. I think the issues is less worry some if you don't have an auto box.
my .02

Roy928tt

Yeh probably just the thrust bearing, will likely get a whole lot noisier before it fails entirely, Kodak it, ie:let it develop.

Short shifter, Hmm, is that a wise idea on a '79 box with its weak synchro rings?

tveltman

Could be torque tube bearings, right?

Iwanna928

I don't know, I quess I will find out. She shifts fine at WOT, just don't try to downshift with the rev's up!

I think I am going to take her down to Bradenton to she what she does in the 1/4 mile. Should be interesting. Get a baseline.

Stephen

Mrmerlin

drag racing an early car is a good way to tear up the transmission better to go to a dyno to get a HP read
Note the 928 isnt a drag racer and the slow er you shift it the longer the transaxle will last

mark kibort

I think its the righter you shift, the longer the transaxle...........

no, cant be torque tube bearings. just a slight pressure of the clutch, doesnt stop or change the torque tube drive shaft from spinning.

A slight pressure on the pedal, and the noise goes away? its something on the throwout bearing I would bet, and it probably isnt anything serious.

Fabio421

Shifting "trick"

shift with your fingertips not your whole hand. Your transmission will shift alot easier and without all the grinding. Try it.

SharkSkin

Sounds just like the way my throwout bearing behaved before it gave up. I heard the full gamut of noises starting from a close match to your description all the way to a godawful shriek when I pressed the clutch.

My take on it is, the bearing lube dries out and the bearing runs stiff; the small spring in the clutch slave no longer exerts enough force to hold the thrust washer against the PP hard enough to keep the bearing turning. You won't see anything on casual inspection because the thrust washer is inside the clutch pack. At this point you can probably save the pressure plate. Once the TO bearing seizes, the thrust washer will wear a groove in the fingers of the pressure plate and it will need to be replaced.

It's probably a good idea to replace a PP of unknown vintage anyway, but it's so easy to drop a 928 clutch you might as well get it out and count on replacing the TO bearing, short shaft, pilot bearing and guide tube. If the RMS is leaking now is a good time to go after that. Just get the right tool for the flywheel bolts and count on replacing them so you won't get stuck in the event they are buggered up or you bugger them up. I have posted details on getting it apart buried deep in this page and detailed assembly and adjustment info on this page.

jmrjames

I have the same kind of noise in my 91 GT. It is an annoying bird chirp to screeching depending on it's mood. If I depress the clutch pedal a small amount the noise ceases.

After investigation, it was discovered that the bushing (2) on the release lever (1) was not installed when someone did some work on the clutch.

Rather than disassemble the entire clutch some silicon was inserted between the ball stud (3) and the release lever (1). This worked for a short time and it was very nice to not screech down the road. Not the kind of attention getting worthy of the car.

However, the noise has returned and I would love to find a solution short of a complete disassemble to silent the demon.

AO

The bushing doe shave a reputation for wearing out over time. You can easily replace it without pulling the clutch.

You need to remove the clutch slave and the air filter housing, then from the top you should be able to slide the clutch arm off the ball stud. This will allow you to slip on a new bushing. Replace the arm and re-install the slave cyclinder and air filter. Should be able to complete the entire job in less than one hour including a beer.

Tampa 928s

I would go to the Dyno, Mark Kunn has a place in Sarasota that does it cheap!
Plus one on the ball cup my 82/Gts did the same thing it rattled and once replaced was quite! Easy quick fix

jmrjames

Sorry I am a little slow but "Dyno" ?