hacker-pschorr

Where did they get the release bearing?

The pedal in both my 79 and 81 are not heavy at all.

aebs

I'm not sure where they got it. Likely Anaheim as it is the closest.

aebs

After getting the master cylinder changed for the brakes, the clutch no longer needs to warm up to avoid grinding.

Next problem is to figure out why the pedal is so heavy to operate, when others like it are much easier to press.

hacker-pschorr

I'm going to take a wild guess the clutch was bled following the master cylinder chagne and your problem with the clutch all along was a bleeding issue.

These clutches can be a real PIA to bleed properly.

I suggest some leg lifts or squats....

aebs

I hike often, so pressing the clutch in is not an ability issue, but an issue of is it supposed to be *that* heavy?

aebs

Actually, the car was hard to shift again this morning. Less hard than before, but not as it should be. So it seems fixing the brakes helped but did not fix it completely.

AO

Bringing this thread back up. My Euro 5-speed has this cold start issue. Most times I have to start the car in gear with the clutch pedal depressed. After a minute or two, it will shift fine. I replaced the soft-line, and thoroughly bled the clutch (damn near a liter for the clutch). I even raised the front of the car with the lift so it was over a foot off the ground, so I highly doubt there is any air in the system. THe only thing I have not done is a reverse bleed.

Clutch engagement is just off the floor. Not sure if that's normal on a double disk clutch or not. On my GT it's very high.

Just curious if anyone has ever figured out the root cause for this dragging issue when cold?

Mrmerlin

Andrew from your info I would suggest to remove the clutch MC piston,
post a picture of it,
NOTE it may not have been modded so your getting shifting issues. this may also include shortening the spring by 2 winds.

Also this may require lubricating the stub shaft so the discs move smoothly,
use the Porsche hi temp grease

GregBBRD

And make sure the gear oil is 75/90 and very fresh. (Mobil 1 works great.)

Porsche had the dealers put ATF into some of these transmissions to solve the cold shifting "problems", however if reverse grinds when you try to engage the transmission (when cold), the issue is clutch release related.

AO

Never touched it myself, but I noticed a nice little access panel has been cut in the fender either by DR or someone else. I'll get a look at it.

But I'm curious how shortening it would help? That seems counter intuitive to me. I would think I would want a longer stroke to actuate the clutch a bit further, no?

All the clutch internals seemed pretty clean and smooth, and I lubed what needed to be lubed with the hi-temp grease. I heard there is some dry-lube you're supposed to use on the adjusters?

I'm pretty sure its a release issue, but I have not changed the gear lube, so I will probably tackle that this weekend too.

GregBBRD

With the "early" transmissions, the thinner the gear oil, the better....especially in cold weather.

That being said, listen carefully to Stan. He's telling you where to start looking.

The only "other" thing that you might want to look at is the routing of the "blue" hose to the clutch master. Seems simple and seems like that should not cause any problems. However, very common to screw this up and induce all kinds of problems. Very common to replace the hose and make it just a "little bit" longer than it was originally.

The blue hose must run gradually and continuously "downhill" all the way to the master cylinder. To accomplish this, it needs to run around the outside of the power brake booster at the 3:00 o'clock position (if you were looking at the front of the booster).

If the hose is too long, it will "droop" down and go around the booster at the 4:00 o'clock to 6:00 o'clock position. This allows the hose to "droop" below the master, which will trap air in the hose, making bleeding virtually impossible.

AO

Thanks Greg. I'll have a peek at the hose as well.

James Bailey

Merlin is talking about the problem with some replacement master cylinders where the plunger which moves inside the cylinder has a nub on the end which is too long and it reduces the available stroke. The solution ( much used and accepted) is to shorten that protrusion and shorten the spring to allow a longer stroke...that added stroke often solves the low release/ incomplete declutching....

worf928

+57,000,000 what JB wrote.

Replacing a clutch MC on DD-clutched 928 is a recipe for poor clutch operation unless you shorten the piston as has been discussed in several threads. The replacement MCs are not identical to the OE MCs. The 'new' ones don't have as much 'throw' so you will get just barely enough clutch arm movement to disengage a perfectly adjusted DD clutch with no worn bits.

AO

Thanks much boys! I'm guessing that's the issue, since the MC has clearly been replaced (by whom, I do not know). I recall seeing those threads but never paid attention to them since my GT was not part of that affected camp. I'll do a search, fix the problem, and report back.