Clutch...Burning Rubber smell

[jimrs2000]

Over the last week or so I have noticed that when "slipping" the clutch for a hill start etc. I have smelt burning rubber, also the biting point of the clutch has moved to the top of the clutch pedal travel.

Car is an 83 911SC, clutch was new about 3 years ago and has around 20,000 miles on it.

Today I checked the adjustment and found zero clearance on the pinch bolt between the two levers and even when the cable was slack I still couldn't get the required 1.2mm gap.

I am suspecting the dreaded rubber centre on the clutch plate....what do you guys think?

[wwest]

'83, shouldn't be, but independent party replacement.....maybe.

[jimrs2000]

Thanks for that wwest....done some more research and the car definitely does not have the rubber centre plate.....now I am struggling...what could be smelling of rubber?

[Jp-oh]

Go for a drive and find a nice long hill and do some pulls up it in higher gears. If you smell it there too you may indeed have clutch issues. I was getting concerned about my clutch as I could like you smell a bunting rubber smell under load in high gears etc. indeed when the input shaft seal finally gave up it turned out it was leaking for a bit and I was having clutch issues

[pors1968]

Was it a new pressure plate whith the clucth replacement.

[jimrs2000]

No just a driven plate.

[pors1968]

Probably not enought strend for that old pressure plate. you have 190hp.

[jimrs2000]

The interesting thing is that there is a good inch of pedal travel from when the clutch starts to bite to when its fully engaged.

[Bob Kontak]

Originally Posted by jimrs2000

I have smelt burning rubber, also the biting point of the clutch has moved to the top of the clutch pedal travel.

Man, I am stumped.

I could smell "clutch" when my 81 kit was tired. Not rubber.

Is it possible for something to get wedged between and you are now cooking it off the friction surfaces? There is not much clearance. Also, you would think, if possible, that the engagement point would be closer to the floor if something was interfering.

[Jp-oh]

Originally Posted by Bob Kontak

Man, I am stumped.

I could smell "clutch" when my 81 kit was tired. Not rubber.

Is it possible for something to get wedged between and you are now cooking it off the friction surfaces? There is not much clearance. Also, you would think, if possible, that the engagement point would be closer to the floor if something was interfering.

That's why I was a bit puzzled too; the rubber smell and no traditional clutch smell. In my case the issue was gear oil leaking in and on the clutch. The smell wasn't my only tell tale sign, the clutch shuddered a bit and I thought there was some slipping in high gears.

[wwest]

Originally Posted by jimrs2000

Thanks for that wwest....done some more research and the car definitely does not have the rubber centre plate.....now I am struggling...what could be smelling of rubber?

Pardon me...but how did you determine that.

Went through the rubber clutch episode in my '78 at ~50,000 miles, been awhile and my memory is foggy but I don't remember any way other than disassembly.

[jimrs2000]

I fitted the plate last time around so I know what it looks like.....I didn't know at that time what the rubber centre one looks like....I researched it and saw the difference is quite clear......unless I am missing some thing again?

[jimrs2000]

Bob, the clutch is juddering....it's not slipping once fully engaged but if I just drop the clutch it slips a tiny bit, that's when I get the burning rubber smell, I have never had the traditional clutch smell since I fitted this plate, could it just be the nature of the lining?


It's my last day at work today for the holidays, I readjusted it as good as could over the weekend....if it's still not good I will drop the engine tonight.

[javadog]

The failure mode for the rubber center clutch disc was disintegration of the rubber, usually followed by a piece of the rubber getting stuck between the friction surface of the clutch disc and the pressure plate or flywheel. Yours sounds like you have a worn out clutch disc. Either way, I'd probably pull it apart and have a look.

JR

[NoYouRelax]

Any chance your transmission seal failed and transmission fluid made it into the plate? I had a leak in that area and it creates slip and a smell.

[wwest]

Originally Posted by jimrs2000

I fitted the plate last time around so I know what it looks like.....I didn't know at that time what the rubber centre one looks like....I researched it and saw the difference is quite clear......unless I am missing some thing again?

Just to be sure...its the clutch DISC that has the rubber center/hub.....

[jimrs2000]

Started to slip in fifth this morning......engine coming out this afternoon.

[jimrs2000]

Ok got it apart and found that the friction material on the plate has largely "flaked" off lots of it in the bottom of the pressure plate and bellhousing, flakes not dust which is unusual, no signs of overheating....the plot thickens....

That's it for now, can't get a new one until Thursday so for now Merry Christmas everyone!!!

[Bob Kontak]

Originally Posted by jimrs2000

can't get a new one until Thursday so for now Merry Christmas everyone!!!

Nice job on getting it out in a day. Wow.

As Mr Creosote says......... “And Don’t Skimp On the Pâté”

Get yourself a proper kit and have the flywheel kissed.

However, pretty east for me to spend YOUR $1000.

Merry Christmas to all. You too, ww. :-)