pewter82

I did a search and from that I'm thinking some sort of early bearing failure in the clutch. The rattle just occured to me tonight, car in nuetral at idle has a slight rattling noise when clutch is out and dissappears when engaged. I had just got through running the car fairly aggressive, and engine was at 175-180 degrees. From reading the prior posts I think I need to have this investigated sooner than later...as it seems it becomes much worse all at once, if not looked into.
Am i close on this thinking its clutch internals or is it the torque tube?...rattle seems to be coming from under me possibly or just in front. The car has 57k on original clutch.

Jason
91GT

fst951

Throwout bearing almost certainly. If it goes away at the slightest disengagment of the clutch, that is the tell tale sign.

Take care.

Jim_H

That's how mine was. Just the slightest pressure and it would disappear.

pewter82

Thanks for the input guys, I'll check it out.

pewter82

BTW what else should a person replace if they are replacing the throw out?

jason

91GT

ErnestSw

It MAY also be the piolt bearing. The Pilot bearing, throw out bearing and the clutch plate should be replaced. If you have the original release arm you'll have to replace that too since the new throw out bearing won't work with the old release arm.
It's not a hard job IF you get in there before something is completelt FUBARed.

mspiegle

i accidently ran mine too long, and the pilot bearing fried. No damage as I was pulling out of my garage... but the car wasn't happy.

When I did mine, i replaced the pilot bearing, throwout bearing, and the little cup that the arm fits into.

If yours breaks again (like mine) then you might have other issues with a bearing in your torque tube, or something isn't straight/aligned properly.

MAKE SURE you get a pilot bearing puller. The free rental from kragen works great. Also get a large socket so you can pound the new bearing back in.

Jim_H

No doubt you will find the release arm cup is fried. My theory is the defective cup starts the domino effect.
Also depending on what parts are in there you may need a new guide tube and/or release arm. I think the big diiference in the release arms is the new ones have the 'shoulders' ground off though you would want to confirm that with the big three.

You can also pull the pilot bearing by finding a nut that is just a tad too large to fit into the the pilot bearing. Grind it down a little so it will just barely fit in, thread it onto a long bolt, then insert the nut into the bearing, jamb a screwdriver along side the nut and then "tighten" the bolt until the bearing pops out.

Cameron

I had this problem as well a short time ago with about 90k miles. I had the rattling noise with the clutch out. I could also feel a significant vibration in the clutch pedal when I revved the engine with the clutch pedal depressed.

It turned out to be the pilot bearing. Upon inspection it was as if it had been bathed in sand. I had the GTS clutch put in. The pedal is noticably lighter now. I didn't consider pedal feel it to be a problem before, but I certainly prefer it now.

.....Cameron
'91 Euro GT

Jim bailey - 928 International

The clutch pressure plate is bolted to the fly wheel and spins all the time with the engine. The clutch release arm is attached to the ball stud on top and clutch slave cylinder bottom but the middle of the arm grabs the release bearing which is also attached to the spinning pressure plate on the spring fingers. When the release bearing starts to fail get more resistance to turning it can start to spin the race that grabs the spring fingers of the pressure plate and make noise . Some pressure on the pedal may stop the race from spinning and make the bearing act like a bearing as long as there is extra pressure pulling back on the release bearing . The pilot bearing in the end of the crankshaft locates the forward end of the short clutch drive shaft AND when the clutch pedal is fully depressed allows the clutch shaft and the clutch discs to stop turning while the engine is still turning so a pilot bearing when failing makes "bearing" noises only when the clutch pedal is down . If the pilot bearing has disintegrated and no longer centers the clutch shaft both the shaft and the clutch disc/discs may be out of balance off center and you get a vibration all the time depending on how far off center the parts happen to land. The upper plastic ball cup bushing which pops into the socket on the upper end of the clutch arm and also on the ball stud screwed in the bell housing keeps it from rattling (metal on metal) but also keeps the clutch arm located so the pull on the release bearing is nearly straight back and not at an angle. When the bushing wears out you can get a slight rattle clutch pedal up as well as a judder shudder when first releasing the clutch (especially if the clutch is slipped a bit much) since the pressure plate is coming in somewhat deformed and at an angle to the discs and flywheel and pressure is not even around the full diameter. The release bearing or throw out is working all the time letting the pressure plate turn which the clutch arm does not but the loads are far far greater when the clutch pedal is depressed . The pilot bearing is working only when the clutch pedal is depressed. The clutch disc / discs basically only wear during that (hopefully ) brief moment when they are slipping as the clutch is being released . The discs would last forever if you never had to slip the clutch . The minimum clutch service should probably be ...release bearing , pilot bearing , ball socket for arm , friction disc and as was mentioned the updated clutch release arm and new guide tube. If the pressure plate fingers are worn from a failing release bearing spinning the race then it needs the plate. The short clutch drive shaft if the splines which engage the discs are worn , replace. If the fly wheel is blued/ grooved , resurface. The early two disc clutch the intermediate plate (which floats between the two discs) also may be worn and need replacing.

figgen

In what year was the clutch release arm modified??

I'm about to dive in and hadn't considered a new arm

Bill Ball

Matt (edco) and I are looking at this old thread for help in diagnosing his rattle with the clutch out only. I have the same question as figgen. If we service the clutch in Matt's 88, do we need a new release arm?

We will follow Jim's advice, as stated above:
The minimum clutch service should probably be ...release bearing , pilot bearing , ball socket for arm , friction disc and as was mentioned the updated clutch release arm and new guide tube. If the pressure plate fingers are worn from a failing release bearing spinning the race then it needs the plate. The short clutch drive shaft if the splines which engage the discs are worn , replace. If the fly wheel is blued/ grooved , resurface.

Jim bailey - 928 International

Yes unless it was already updated which is unlikely.

cdbtx

My plastic bushing failed (I ignored the rattling), the release arm came off pushing the release bearing through the pressure plate - thus when I opened the inspection plate on the bell housing - all the pressure plate fingers fell out... well not all - there were two or three left intack..

Thus my neglect made the decision for me as to what parts I should replace..


Chuck

83 Kiln Red 928S