Broken Clutch

wilke3169 · 02-07-2005, 08:53 AM

My clutch seemed to start losing adjustment a week ago. On Friday it went away all together meaning it will not disengage. I adjusted per spec and the lever travel underneath seems to be fine but there is no disengagement whatsoever. If I fully depress the clutch pedal with the engine cranked there is a high pitched squeal. I am quite sure an engine drop is required to further diagnose but does anyone have suggestions before I go looking further?
Thanks
Kevin

sammyg2 · 02-07-2005, 09:46 AM

Could be several things, the one that jumps out is the problem with OEM 911SC clutch discs.
They came with rubber centers which work very well, for a while.
Eventually the rubber starts to break and chunks get caust in the works, preventing the clutch from disengaging. If it's the original clutch this may be a possibility.
Other things to check are throwout bearing, clutch fork, clutch cable, roll pin in the pedal assembly, in other words, all the things that transmit the force from your foot to the pressure plate.

How does it feel when you depress the pedal, the same as before?

wilke3169 · 02-07-2005, 10:54 AM

The clutch was replaced per PO documents. The effort to depress the clutch is much less than before. I did have this done while I was under the car and the lever there is actuated by the cable so I am pretty confident the cable is not the issue. From reading posts found via search it appears the clutch fork or other internal devices are likely suspects. Just didn't want to miss something obvious.
Thanks
Kevin

sammyg2 · 02-07-2005, 11:49 AM

I agree, prolly the clutch throwout mechanism. There's an inspection window in the tranny belhousing to look through but I've never been able to see anything through it with a mirror and flashlight, I pull the starter and look through there to align everything when bolting in the engine.
Pulling the start is a PITA but easier than dropping the engine, if you did pull the starter at least you could see what's happening inside there.
Youll prolly still end up pulling the engine so chances are you won't save any work. Your call.

wilke3169 · 02-16-2005, 05:58 PM

I do believe this is the problem. I pulled the engine tonight and it was pretty obvious.

Groesbeck Hurricane · 02-17-2005, 04:27 AM

Well, I was going to tell you that the clutch cable could have been stretched, but looks like you found a a different source. Been there! Easy fix! Now, while your in there...

Rick Lee · Rick Lee's Garage

Just be sure you align the new fork into the t/o bearing on reinstall, or you'll have the exact same feeling first time you push the pedal in.

wilke3169 · 02-17-2005, 05:49 AM

David, I do have a long while I'm in there list. This just forced my hand which is a good thing. My car now has 170.000 miles so it has all of the normal issues. I am sure I will be here with questions and comments as I go as well as photos asking the many experts here for opinions and comments.

Kevin

rching · 02-17-2005, 06:08 AM

I had the same problem in my carrera, except the throwout arm was just cracked. It would work fine sometimes, chatter sometimes, wouldn't dis-engage sometimes, get stuck in gear sometimes,....kept checking everything. Sometimes when it just breaks, it's easier to fix. Intermittent sometimes it works, sometimes it doesn't, drives me crazy!

kqw · 07:25 AM

Now that you are in there:

You mentioned that the clutch was replaced by the PO but it may be that only the certain parts were replaced. Check the records you have from the PO and look to see what was done.

When I replaced my clutch I had the following done:

Pressure plate
Disc
Throwout bearing
Release bearing fork !!!!
Pilot bearing
Guide tube
Main shaft seal
Rear main seal
9 pressure plate bolts
9 Flywheel bolts
Clutch cable
Clevis fork and pin
re-surface flywheel.

Before you button up your car check these items or you may be back in there for something else.

Thanks

john walker's workshop · 02-17-2005, 07:23 AM

make sure you lube the mainshaft splines and around the guide tube. inspect the guide tube for wear also. they're dry as a bone, not good.

wilke3169 · 02-17-2005, 07:33 AM

The guide tube and throw out bearing seemed to take some abuse, I assume in the time the arm was going away. I plan to at the very least replace these items, rebuild the fork assembly and closely inspect the clutch, pressure plate, and flywheel. The clutch was performing normally it seemed until this occured. John, the smaller helper spring on the small clutch lever is missing. Any chance this could have caused the damage. Doesn't matter just trying to put a finger on why things happen. I do appreciate all of the advise and will certainly check anything you guys can think of.
Thanks Again,
Kevin

kqw · 02-17-2005, 07:42 AM

Just a note: if you remove the pressure plate and flywheel bolts remember these are stretch bolts and should not be re-used....

yelcab1 · 02-17-2005, 07:45 AM

Quote:

Originally posted by kqw
Just a note: if you remove the pressure plate and flywheel bolts remember these are stretch bolts and should not be re-used....

I don't think this is true anymore for these "newer" SC models. Please do a search.

I have a used fork, if you need one.

kqw · 02-17-2005, 08:21 AM

Quote:

Originally posted by Wayne at Pelican Parts
I know plenty of engine builders who reuse them, and have never had a problem. That said, I always use new ones - it's cheap insurance...

-Wayne

randywebb · 02-17-2005, 09:55 AM

right - someone did a search and found PAGs TSB on this - the bolts were changed at some point in the late 1970's - no change needed on an SC.

Superman · 02-17-2005, 10:30 AM

I know of no one who reuses flywheel bolts. I won't. Pressure plate bolts, yes. Flywheel bolts, no.

Be sure you replace your oil thermostat o-ring while the engine is out.

yelcab1 · 02-17-2005, 10:40 AM

I have re-used fly wheel bolts on my SC and Carrera (with a little red locite) and never a problem. I put 125K miles on the Carrera, it never came loose.