A

[EDIT] Oops, it's a 1987 4+3 Coupe.


PROBLEM
Clutch pedal is spongy through most of its travel. When the engine is running, you cannot put it in reverse because it GRINDS badly, you cannot put the car into any forward gear, it just won't go in (I'm guessing this is because the forward gears are synchronized).

THE ATTEMPT AT REPAIR
New clutch, new master cylinder, new slave cylinder. We bled and bled and bled and bled some more. NO bubbles.

THE RESULT
The clutch pedal is still spongy through over 50% of its travel and then becomes firm the rest of the travel (I'd say the "firm zone" is only maybe slightly more than the last 25% of the pedal's travel). Reverse still grinds and won't go in and you still cannot shift into forward gears (while the engine is running). Just as before, if you put the car into gear (we'll say first gear), press the clutch pedal to the floor, and start the engine, the car will go forward. If you start it when it's already in reverse the car moves backwards.
INTERESTING THINGS TO NOTE:
***The old master cylinder had a spacer between it and the firewall which I re-used for the new master cylinder
***I have to depress the clutch pedal some to connect the link at the top of the pedal to the rod from the master cylinder.
***The plastic bushing between the link at the top of the clutch pedal and the rod from the master cylinder was all chewed up, but this item was replaced less than 7000 miles ago.
***When the pedal is being pressed through the "spongy zone", the slave cylinder IS pressing the clutch fork.
***When the pedal is ON THE FLOOR, the clutch fork still has about an inch (maybe a little less) that it could travel before hitting the bellhousing.
***My car HATES me!


It seems like the clutch MUST not be fully disengaging. It also feels like there must still be air in the system somewhere because the pedal is so weak; when my car was drivable, the pedal was always very firm. But I've BLED the system over and over and got no air bubbles.

That's all the detail I can think of right now. HELP!!!! :cry :cry :cry


[Modified by A, 8:51 PM 8/17/2003]

bogus

hm... Bent clutch fork?

bad linkage?

the best way to bleed the clutch is to use a Phoenix Tool. It will allow you to pump fluid up from the bottom, pushing all fluids up with it.

A

A Phoenix tool?

bogus

yea. it is a hand pump thing that will push fluid up from the bottom. whilst pushing, all air goes out the top.

frank moran

are you bleeding it with the slave removed from the bell housing and at a 45 deg angle?? you cant bleed this unit with the slave on place. frank

ericcer

This is what I do for bleeding. If you are replacing the master or slave, bench bleed it first. Then I remove the master cylinder lid and rubber insert and reverse bleed the system via the slave. You remove the slave keeping the lines connected and bleed valve closed by pumping the slave using the slave push rod. Do this about 10+ times. Next bolt back in the slave and pump the master 50+ times. Then fill master to proper level with rubber insert and screw on the lid.

This does fairly well. As stated from ZF Doc website, the system self bleeds so I find that after a few days driving the pedal gets little firmer.

A

Hmm, my master cylinder does not have a rubber piece under the cap. Does this matter? I have a friend with a reverse bleeding tool and I'm going to try that next.

CentralCoaster

Your slave cylinder should be moving ~3/4 of an inch.

Crawl under the car and remove the clutch fork rubber boot partially, compress the slave cylinder piston into the bore, and remove the pushrod and boot.

Now, move the clutch fork freely to see at what point it moves the throwout bearing into contact with the pressure plate diaphragm spring. If all your clutch movement is used up in the free-play, you won't feel much feedback.. and it'll feel spongy.

The spongyness goes away when the pressure plate spring applies force on the linkage... it seems like you either need a longer slave pushrod, or to move that master cylinder closer to the dash, by taking the spacer out.

The fact that you had to move the pedal down to connect it means that you're already losing that much movement.


Anyways, long story short, the slave push rod movement of 3/4" will tell you whether or not its a fluid problem or a linkage problem.

A

I'll try that. IT's at least something I haven't done yet...

Is there supposed to be a spacer between the firewall and the master cylinder?? It seems like it's supposed to be there...