Clutch Pedal Height and adjustment 964

[shaker71]

Vehicle 1991 C4

I replaced my clutch master cylinder today and noticed that the clutch pedal has about 50mm freeplay before it engages the master cylinder.

History: My original problem was that the clutch release was near the floor and got worse when the car warmed up. I decided to replace the clutch master cylinder and the slave cylinder then power bleed the clutch. Prior to starting the job I noticed that I could pull up on the pedal and increse the travel by 50mm. Pulling up on the pedal did not change the master cylinder travel it was "slack".

What has me worried is that when I measure for pedal travel to make the adjustmnet I come up short of the travel spec. I have about 115-125mm of total travel instead of 145 +/- 10.

Through observation it appears that the "slack" is in the part that attaches the master to the pedal cluster. (The part the master clips on to) Please advise as to whether I need to replace a pedal cluster, just a part, or I'm missing something.

Thank you,

Bill

Note: Later that night

I went into PET and found an illustration of the pedal cluster (702-00). It appears that there is a dowel pin #8 that runs through the lever #9 and clutch pedal shaft #2. I have seen dowel pins fail before and still have enough detent to operate a lever, but the amount of pressure needed to exercise this clutch seems excessive and unlikely that the system would not have totally failed already. If you have ever seen such a failure please respond. Also, if you have ever replaced this pin I'm wondering if I can perform this operation with the pedal cluster in the car?

[JonSeigel]

I'm not sure exactly what the problem is. If you push up the underside of the clutch pedal with the top of your foot, does the pedal sort of snap into place at the top? If so, it's probably the infamous "hanging clutch" that is a problem on many 964s and 993s. There are several alternative solutions, but no consensus on which one actually works in the long run.

Search the main 911 board and/or the Rennlist 964 and 993 boards under "hanging clutch" for ideas.

Good luck.

Jon
'93 C2

[shaker71]

I've read the hanging clutch info on Renn and have the updated part info. It seems that the part on the 993 is "notched" where the 964 part is held in place by a roll pin. I appreciate the input, but think that while the area of failure is the same as the 993 the causal part is of different design.

Thanks,

Bill

[tshih]

Hi Shaker,
How are you bleeding the clutch hydraulics? There may just be air in the lines from improper bleeding of the system. I always open the slave bleed nipple on the gearbox and attach a clear tubing to a bottle. Then manually slowly move the clutch pedal back and forth the full distance while someone else always keep adding the brake fluid to the chamber to the top level. After no air bubbles are seen in the tubing then close up the slave nipple and the pedal is all the way up.

I normally do not try to adjust the factory setting of the master cylinder piston attached to the cluster.

[shaker71]

I haven't bled the clutch yet still waiting for the new slave from the dealer. But, the old slave is off the car and the mechanical pedal traval available is under spec. So I know that won't get any better by bleeding the clutch system.

Something is wrong with the pedal cluster or the new clutch master cylinder. I'm wondering if the clutch pedal shaft my have torsionally twisted and thats where the 20mm is lost. seems like a clutch part would be tougher than that.

I'm planning to install the new slave Monday and power bleed the clutch. I'll forget about it if everything feels O.K. Otherwise I'm pulling the pedal cluster.

Bill