Clutch problems -79 4,5
#1
Instructor
Thread Starter
Clutch problems -79 4,5
Hi,
The car has been standing still the 10 last years, so I guess that something needs replacement. When I first got the car, it had very long clutch travel, before the clutch disengaged(also noticed by the workshop doing the last service ten years go), and the other day when I was going to school, the clutch pedal stuck to the floor. After bleeding it, it worked fine(actually better than when I got it) but today, the brake reservoir was empty of fluid once more.(and ofc the pedal was stuck to the floor)
I suppose this means I have to change the blue hose, but perhaps I should rebuild the master and slave when I'm at it? Any great tips?(as I understand this is probably one of the worst jobs on a 928)
Thanks
The car has been standing still the 10 last years, so I guess that something needs replacement. When I first got the car, it had very long clutch travel, before the clutch disengaged(also noticed by the workshop doing the last service ten years go), and the other day when I was going to school, the clutch pedal stuck to the floor. After bleeding it, it worked fine(actually better than when I got it) but today, the brake reservoir was empty of fluid once more.(and ofc the pedal was stuck to the floor)
I suppose this means I have to change the blue hose, but perhaps I should rebuild the master and slave when I'm at it? Any great tips?(as I understand this is probably one of the worst jobs on a 928)
Thanks
#2
Rennlist Member
Where is the fluid going?!?!?! It just doesn't disappear, this is a closed loop system. You obviously have a leak. Bleeding the system removes air bubbles. However, your leak is bringing more air bubbles back hence a circular problem. IMHO, the only way to to successfully bleed the system is with a prostyle brake bleeder, otherwise lots of time is wasted, two people with some tired limbs.
- Identify leak
- Check blue hose running from master
- Check the black hose going to the slave cylinder
- Check the slave cyclinder iteself for leakage
- Check the clutch pedal area inside the car and check for leakage / puddle
- Check ALL BRAKE LINES!!!
- Remember the Clutch/Brakes share the same master cylinder - I would not drive the CAR for safety reasons until this is identified and fixed. There are lots of articles on the how to when you run the search.. Good luck!
- Identify leak
- Check blue hose running from master
- Check the black hose going to the slave cylinder
- Check the slave cyclinder iteself for leakage
- Check the clutch pedal area inside the car and check for leakage / puddle
- Check ALL BRAKE LINES!!!
- Remember the Clutch/Brakes share the same master cylinder - I would not drive the CAR for safety reasons until this is identified and fixed. There are lots of articles on the how to when you run the search.. Good luck!
#3
Instructor
Thread Starter
... and for all others that may have the same problem; it was the slave that was the sinner. Plenty of rust inside, torn o-ring. The brake fluid litterary flushed right trough, and out in the bellhousing. Took the master out as well, and I'm honing them up, and replacing seals tomorrow The blue hose was fine, except for a small blockage that may be small bits of sealings, old brake fluid, and water. Flushed it three times, now it seems fine.
The brakes are fine. Rebuilt them just a couple of months ago. Luckily for me, the PO also had changed the flexible clutch line.
The brakes are fine. Rebuilt them just a couple of months ago. Luckily for me, the PO also had changed the flexible clutch line.
#4
Instructor
Thread Starter
OK. Honed and rebuilt the cylinders, now it's working, but nothing better than before. Pedal seams weak about 1/2 way, then it begins to harden, but don't disengage the clutch before all the way in. Now, does this mean I still got air, or is it something else that's wrong? Some of the seals had an extremely tight fit, but hey, it works so I suppose they are correct.
#5
Rennlist Member
Rennlist Site Sponsor
Sounds like air in the system.
There was a post on here the other day on a clever dodge for bleeding the clutch.
Get a clean piece of rubber or plastic tubing that is a snug fit on the front brake bleeder valve and the clutch slave bleeder valve. Clean both bleeder valves.
Slip the hose onto the brake bleeder valve and open it enough to fill the hose with fluid. Slip the filled hose onto the slave bleeder valve, and open it. Slowly pump the brake pedal several times. This should force fluid thru the clutch slave and master, carrying the air along with it. The fluid and air should end up in the master reservoir, and hopefully this will remove all of the air from the clutch system.
Let us know how this works...
There was a post on here the other day on a clever dodge for bleeding the clutch.
Get a clean piece of rubber or plastic tubing that is a snug fit on the front brake bleeder valve and the clutch slave bleeder valve. Clean both bleeder valves.
Slip the hose onto the brake bleeder valve and open it enough to fill the hose with fluid. Slip the filled hose onto the slave bleeder valve, and open it. Slowly pump the brake pedal several times. This should force fluid thru the clutch slave and master, carrying the air along with it. The fluid and air should end up in the master reservoir, and hopefully this will remove all of the air from the clutch system.
Let us know how this works...
#6
Rennlist Member
It is super hard to get all the air out. I would sometimes spend many 10s of hours trying to bleed the air out until I learned (here) how to burp it. Search for burp.
Trending Topics
#8
Instructor
Thread Starter
Well, fun fact: It's been sitting still the last few weeks(due to the clutch pedal ofc), and now that I've used it two days... Suddenly the clutch pedal works perfect! Either it's been lacking some fluids in the cylinders, or the air has escaped in some mysterios way. But it works for me!!