BruceWard

I was out doing some spirited driving in the 968 with a friend and his Boxster this evening. Unfortunately when we turned around after a few fast runs my tranny didnt want to shift. Thought I was doing it wrong so I tried again and it went in first. When I released the clutch the car was moving forward but was jumpy (bumpy), not right. I stopped and backed up which also felt wrong.

I thought it might be a broken balance belt since that had been changed but I got out and took the cover off and the belts looked fine. The engine revs freely and without vibration so that is unlikely to be the issue. Oil pressure and temperature were normal.


So my first guess had been the clutch, but the overwhelming fear of belt breakage had me checking it first. I let the car cool down to see if it improved. It did a little and I thought perhaps enough to get home. Although as I drove it got worse. It seemed like the clutch was not disengaging and at times was not fully engaging. Although there was some clutch smell it was never overwhelming and could not be smelled in the car.


At the first stop sign I found that the cluch was not disengaging and had to turn the car off to downshift. I was hoping to get home and the car felt normal as long as I didnt try to use the clutch so I kept going. The next issue was that after about 5 miles of driving when I pressed the clutch it stuck to the floor. I pulled it back up with my foot, and I could hear the clutch spinning. The clutch got very hard and stuck half way up and would not move. I pulled over into a parking lot, turned the car off and called a flatbed truck.


Now the 968 is back in my garage, safely at home but broken.


So far two mechanics who heard the story have thought it might be low on fluid, or have a slave cylinder failure. A third mechanic who verified the fluid was full and tried to mash on the clutch pedal thinks it seems like a throwout bearing.


So I hope you will offer your suggestions, speculation and any methods to diagnose this failure.


Thanks

sayporsha

What you describe could be caused by a broken spring in the clutch disc or pressure plate, where a piece of it falls between the friction surfaces and prevents the clutch from fully disengaging or engaging. It could also be caused by the throw out bearing or a neighboring part. In any case, it sounds like you need to remove the trans, torque tube & bellhousing to get at the problem. Before you do, assume the position, look under the dash and make sure your clutch pedal linkage all looks in place.

Jay Wellwood

Uh oh....btdt on the 928 (tranny & TT removal). Just curious if you have to remove all of that stuff to access the clutch on a 968 - you don't on a 928.

RajDatta

Good call Jay, to get to your clutch in a 968, all one has to do is remove the side window on the bell housing and you have full access to it. You can disconnect the torque tube shaft by opening the round hole on the torque tube and removing the cheesehead bolt. This will allow the shaft to be free and you can slide it back to free up the clutch mechanism from the shaft.
At this point you can go thru the window to remove the pressure plate and other hardware and inspect to see what went wrong.
As stated, it can be a bunch of things but whats throwing me off is the fact that your pedal stayed down. When you depress the pedal, it forces hydraulic fluid down the clutch line into the slave cylinder which pushes on to the fork. This action on the fork pulls on the release bearing and thus disengages the pressure plate disk from the clutch disk. You need to remove all the pieces to see what happened.
You will need a set of triple square sockets. Bob knows how to find them. There are 9 bolts holding the pressure plate. You will need to turn your engine to get to all of them. Always turn the engine clockwise. Also, remove the needle which is held by 10mm bolts on the outside of the housing.
If I remember correctly, didn't you just recently do a flywheel?
Raj

BruceWard

Raj, recently did the timing belt which involved locking the flywheel. The 968 has 57K miles on it.

Are the triple squares the same as the ones on the balance belt rail under the crank only larger or a different shape?

RajDatta

Bruce, no thera re more like torx, only they have 12 sides to them. Usually if you try to use a torx wrench, it will strip the head so make sure you get the proper sockets.
Something mechanical has failued in the system. Open the bell housing window by the slave cylinder and depress the clutch, see if you see the rod and the fork move. That should eliminate the slave cylinder.
Let me know how you progress.
The triple squares are available thru autozone if I remember.
Raj

sayporsha

Didn't know you could R&R a 968 clutch like that. Assumed it was like the 951.

BruceWard

I picked up a set of triple squares today. Ill let you know how it goes. Thanks for the advice.

BruceWard

Havent taken it apart yet, but here are some pics, would appreciate your comments. The clutch is stuck in the up position and I cannot press it down.

View port


Starter hole


General area

BruceWard

Ok I took it apart and have additional photos. Now that its apart Im not sure what to replace. How can I tell if the clutch is ok?

I could easily push the lever that the slave cylinder pushes on with my finger, it had no resistance and no desire to move to either side. Is this normal?

First the slave cylinder, it looks dead to me



and




Now what I can see of the clutch












And finally the stuff that scares me, rough edges and the small pieces that may have fallen off

RajDatta

Your clutch is completely toast. You need a complete clutch job. Hopefully the damage is minimal to your flywheel. All these pieces in there are part of the disk and it seems like its shredded.
Not to worry, you should be able to perform this. A few things to consider.
Rear main seal.
Complete clutch kit including needle bearing, shaft guide, clutch plate, pressure plate and throw out bearing.
You might need to remove your flywheel in case you have greeves and have it machined.
Also check your DMF to make sure its in good health.
Let me know if you need help. I have some decent spares that I no longer need in case you are tight.
Raj

BruceWard

Would the 20 piece clutch package from pelican parts cover what I need?

http://www.pelicanparts.com/catalog/...clutch_pg1.htm

Here is their blurb

The complete 944 clutch package contains every little piece that you will need to perform the complete clutch replacement on your 944 or 968. Specifically, the package contains:
New 944 Pressure Plate
New 944 Clutch Disc
New 944 Throw-out Bearing
9 Flywheel Bolts
Pilot Bearing
2 Release Lever Shaft Bearings
Slave Clutch Cylinder
Flywheel Seal
Throw-Out Bearing Guide Tube
Clutch Alignment Tool
Clutch Master Cylinder

Our clutch kits come only with the improved 944 spring centered clutch disc, and are manufactured by Sachs, the Porsche OEM (Original Equipment Manufacturer) supplier of clutch components.


With this package, you will have everything you will possibly need to do a complete clutch job, and also have the security of knowing that you didn't forget something. You can eliminate the fear that you may need to tear open your clutch again because a small part has failed. The complete package is great insurance against having to perform more clutch work.
NOTE: Sometimes the clutch fork wears out and needs replacing along with the clutch fork bearings listed below.

RajDatta

It covers everything except not sure if I would go ahead and swap the Clutch master cylinder and Slave Clucth cylinder.
Also, 968s don't come with a spring centered disk, so make sure they send you the correct parts.
Pray that your flywheel is good. You will only be doing the rear main seal and pilot bearing if you remove the flywheel.
Let me know if you need any further assistance.
Raj

BruceWard

Raj, does the slave cylinder look healthy to you? I was thinking that it looked bad, but if you think its ok then I guess there is no need to change it. I thought the master or slave cylinder was probably what had stopped the pedal from moving.

RajDatta

The slave cylinder is not expensive at all at around $30 or so. I would change that the most.
The reason nothing seems to be working is that you have your disk material is stuck somewhere which is stopping normal movement.
Raj