'88 Carrera Clutch pedal does not return

[Rubatoguy]

Driving home the other day I went to depress the clutch and realized that it was halfway towards the floor. I found I could hook the pedal with my foot and pull it back up. Once the pedal is back up, the clutch works normally except that it only returns about 75% of the way each time, until it is back at the floor. No problems with clutch engagement or disengagement.

I'm thinking either a leak in the hydraulic system or a broken pedal return spring. What is the best way to determine which is the likely culprit?

Todd
'88 Carrera

[Quicksilver]

The "pedal return spring" is the pressure plate. There is a "helper spring" but that isn't your problem.

Sounds like it needs to be bled but the "why" it needs to be bled needs a look too. Could be bad master or slave. It is common practice to change both on an older car that has darkened fluid that looks like it might have metal in it. If one was worn then the other will be questionable.

- Also there is another low percentage possibility. It could be a partial failure of the roll pins in the pedal assembly. To check simply remove the floorboard and look to see that the pedal and the bellcrank to the master are moving in unison. (BTW - You can't use a normal split roll pin for the pedal shaft. It has to be the factory item.)

[boyt911sc]

Check and inspect the brake fluid level at the reservoir. Look and inspect the pedal cluster for any sign of sign of abnormalities like collapsed or broken pin. Pressure bleed the clutch slave and find out if the bleeding process restores back the clutch pedal up and high. BTW, the brake and clutch pedal have separate brake fluid supply reservoir.

Tony

[megerian]

I had the same issue, its not a return spring, but likely a leak in the clutch slave cylinder.

FYI - mine was noticeably worse in cool weather.

[spidklr]

Same here - in my case it wasn't actually stuck, but getting there/ slow return near the top. My car needed both a clutch master cylinder (visibly leaking) and pedal box rebuild with new bushings, but now it's all happy.

[yelcab1]

Change master and slave, change fluid, bleed.

[88911coupe]

what yelcab says....I had the EXACT same symptom. In my case I replaced the master first...didn't fix it, then did slave and that fixed it. About 6 years ago and the symptoms coming back.

[rpetty01]

Mine did the same thing. It was the pin in the pedal cluster.

[Big Mack]

Same symptoms - I replaced the master, leaking slave and flex hose before driving to Rennsport. Had the car on a lift for the first time (new garage) and was able to reach the slave bolts with an "S" curve Gearwrench - made it much easier. Worked the master out and up without removing the pedal cluster by moving wire bundles to make space. Pressure bleeding was a long and tedious process, but after about 1.5 quarts it blew out a big final burst of bubble diarrhea and the pedal firmed up.

Must have disturbed the driver's side heater valve control cable when reaching up to the slave, so I got to enjoy full heat all the way up and back - nice touch.

Good luck.

[Rubatoguy]

So, I took a closer look and there are no leaks at the master for the clutch - but the accordion boot is torn, and the rubber from the clutch stop is missing. I don't see any springs on the pedal cluster, and the pedals have some play in them in a lateral direction. (Photo attached.)

The interesting thing is if I push the pedal about 1/4 of the way by hand, the pedal will travel to the floor by itself. If I hold the pedal to the floor, in about a minute or so, the clutch will slowly engage. I have not checked the slave cylinder yet, but I am thinking that it is probably leaking.

[Rubatoguy]

Here is a video of me pushing the pedal by hand about 1/4 of the travel, and you can see the pedal traveling to the floor on its own.

https://youtu.be/hyAJCc2UDoY

[Dan J]

To the above I would add the rubber hose that connects to the slave
I've had several of these fail internally in the last several years
So replace master,slave and hose

[3literpwr]

Similar issues with my 87 and the master was not leaking. I changed it and no changes. Ended up being that slave on the trans. They don't always leak.

[ganun]

Originally Posted by Rubatoguy

........
The interesting thing is if I push the pedal about 1/4 of the way by hand, the pedal will travel to the floor by itself. ....... I have not checked the slave cylinder yet, but I am thinking that it is probably leaking.

There is a big spring to help push the pedal down but its assistance starts after the first 1/4" or so of travel. It uses a mechanism that's hard for me to describe with a small lever etc
The Bently manual shows the adjustment for assist by rotating a small boss .
Bottom line; it's normal.

[Rubatoguy]

How would you test to determine if the pin is broken?

[RedCoupe]

Originally Posted by Dan J

To the above I would add the rubber hose that connects to the slave
I've had several of these fail internally in the last several years
So replace master,slave and hose

+1 on replacing the rubber hose.

[shrtshck]

Same symptoms, mine was the slave cylinder.
Fluid rarely ever gets bled, eventually the moisture ruins the seals.

[billjam]

Originally Posted by Rubatoguy

How would you test to determine if the pin is broken?

I had similar symptoms not so long ago. The problem was a broken roll pin (arrowed).
To test for this, check that when the pedal is operated, the shaft moves with it. Looking at the end of the shaft, if there is any movement between shaft and pedal, the pin is broken.