JPP928

Hi, I recently bought an early 1983 928S 4.7L manual which is primarily going to be used as a track day car. When I got the car it had been standing for over 10 years and the clutch pushrod from the pedal to the master cylinder was missing - I later found it whilst stripping out the interior. Several months and lots of hard graft later I'm re-assembling everything but when I reassembled the clutch pedal with the pushrod it appears to be well and truly jammed (up). There seem to be several postings about clutch pedals being stuck down but this is the opposite! The pedal won't shift at all, indeed the bulkhead starts to flex first!

To try and establish where the problem lies I'm going to release the slave cylinders bleed nipple and see if the clutch pedal then moves - this should establish if the problem's with the master cylinder or somewhere down the (hydraulic) line. I was wondering if there's anyone that's experienced this problem themselves before I start the painful process of stripping things down!

Dave928S

You have no choice but to go down the path of elimination. What you're proposing is a good start ... I'm thinking seized master, slave, or release bearing assembly on the guide tube.

If it's the release bearing frozen on the guide tube you'll need to take of the lower bell housing cover (back two bolts are a PITA and you need to drop the exhaust to get them out). With the cover off you can jemmy the release arm which might free it up. If you don't want to take the cover off, you could try taking the slave out and putting a piece of timber dowel in place of the push rod, and tap it to attempt to break the corrosion.

If it is seizing of the release arm, I think you'd be better off taking the cover off, because it's also likely that discs will be frozen to the flywheel/inter/pressure plates (which could also give you the solid no release) ... and you'll need to see how bad the corrosion is and what else might be affected.

SteveG

I haven't been under an '82, but I'm pretty sure the problem is the same. The bolts referred to are simply too long and back out against the pipe, so the exhaust has to drop. If you go this route, cut them down so next time you don't have to drop the exhaust. I think they are actually not needed, some just leave them out.

Mrmerlin

since the car has been sitting for ten years remove the clutch MC and flex hose, the blue hose and slave cylinder .

Replace the complete system with new parts use ATE Blue fluid .

NOTE check the new MC piston to see if it matches in size the old part you may have to trim off 4.5 mm of the tip and cut down the spring.

Replace the clutch release arm bushing as well. This is at the top back of the engine you can see the end of the arm its under the aircleaner base
You may need a new throwout bearing and pilot bearing

Also replace the brake master cylinder and 4 flex brake lines

Don Carter

Don't use Valvoline Synthetic Brake Fluid! (See my other recent threads about swollen seals)

Hilton

My guess is no fluid in there, and subsequent corrosion in the master has jammed the piston.

JPP928

Blimey, looks like I've got a busy weekend ahead of me. Thanks to all of you for your suggestions... I particularly like Hilton's idea, mainly as I hadn't considered that as a possibility! I'll keep everyone posted on the results!

Mrmerlin

you will drive many more miles without having to work on your clutch if you follow post 4

JPP928

Right then, the rain held off long enough for me to grovell under the car and loosen off the bleed nipple. Yep, the master cylinder is well and truly siezed - new one ordered. Looking closely at the rest of the system it appears that the slave's been changed already but whoever did the job thought that it was a good idea to replace the piping with a single piece of solis copper tube - no flex fatigue issues there then! Will update later...