Kerry Chadderton

Guys... I'm at wits end with bleeding this clutch. This is a stockish '84 model. The pedal was on the floor when I bought it. I flushed and bled it. It worked fine for a while. Then it would occasionally stay in the floor. I would pull it up with my toe and it would work for a while. I rebuilt the slave cylinder, which did have some pitting but not enough to cause me alarm. It worked for a while and then the same behavior.

Now I'm reassembling everything during the clutch replacement. I've also replaced the clutch fork, bearings and shaft. I got to the slave cylinder. Installed and bled it. Same behavior! There is no leaking fluid anywhere. Not even on the inside of the firewall!

I have pressure-bled it, vacuum bled it and two-person pump bled it. I've bled it level and with the car standing on it's nose. There is no leaking fluid and no loss of fluid. What the hell is going on? Do you suppose either the slave or master is leaking down internally without leaking? Is that possible?

Also, what's up with this spring assist thing that Porsche put on the clutch pedal? From the beginning this thing has overpowered the master so that when two-person bleeding, you need a string to pull the pedal back up during the process.

Sorry for the long post. I just needed to vent. And I need help!

Merry f-ing Christmas!

kingston944

I think the master. I did both at same time both mine leaked and if not more then likely will fail soon after just replacing one. I had a friend pump the pedal while I did slave bleeding and all seams fine now . Good luck.
I hear you on the Merry Merry Xmass lol

944Ross

The spring gives an "over-center" feel to the clutch, usually missing on hydraulics, and helps reduce the pressure needed to hold it all the way down.

You must have an air leak into the system, likely at the M/C

Kerry Chadderton

That's two for the M/C ! I guess I might like the intended purpose of the spring if the system worked right

When "pump" bleeding, have either of you had to use a piece of rope/string to pull the pedal back up, or am I doing something wrong?

944Ross

It could be the hose going into the M/C, or the pipe out of it. If it isn't leaking visibly, I'd at least check them out first.

83 944

Check under the carpet under the dash for leaks . Also when you bleed the clutch jack the rear as high as you can get it then bleed it . Once you get a half pedal pump it 3 times fast and let the pedal slap up. Like put you foot at the bottom of the pedal and once you hit the bottom slide your foot off. That should give you a full pedal. It works everytime for me.

+1 on checking the blue hose( if stock) from the master clutch cylinder to the brake fluid resivoir. Those usually get really brittle.

It sounds to me you are getting air in the lines from somewhere. Like someone already said also check the little black piece that is connected to the mast clutch cylinder to the blue hose. Make sure that bad boy is in there nice and tight . Push down on it. Watch it when you push in the pedal to see if bubbles comes up around the rubber bushing holding it in there.

If you have down all of this then check the back of the clutch pedal and adjust the rod that screws in the back of the pedal to make sure it's nice in there and not just In the hole not threaded because it makes sense to menthat it falls out and somehow when you pull the pedal up it puts itself into the hold again then pops back out over times.

All of these things has happened to me . So I hope it helps. Keep your head up and youll get through it!!

mazdaverx7

if you do find that the clutch master cylinder is at fault its best to replace the clutch master and slave cylinders at the same time. one new and one old component in the hyrdaulic system can cause failure of the older part. you issue does sound like a faulty hydraulic component. you will find that if you look under the dash and find the clutch pedal, you will see a pushrod extending from the pedal bar itself and it will set into the clutch master cylinder's piston. if you see any leakage or seepage from the piston area then the seal on the piston has failed and requires rebuild or replacement of the clutch master cylinder. the slave cylinder is uses the same principal, but you will see seepage around or from the flexible boot.

Mark944na86

I would think the only thing you are doing wrong is trying to "pump" bleed, rather than pressure bleed.

Well, pump bleeding is not wrong, so much as making life much more difficult for yourself than you need to. I've done it both ways -- pressure bleeding is the only way to go. Seriously.

JohnKoaWood

Dude, replace the master and line, pressure bleed the system and be done with it.

TheEdge posted a DIY to swap to AN fittings and Braided hose, I did this on my 951 and it is BEAUTIFUL.. not to mention it lets you bleed the slave with it ABOVE the master...

http://reutterwerk.com/forums/showthread.php?t=12834

some folks have had problems getting the right parts from the supplier, I guess I got lucky, as I ordered, and the install went smooth as... you get the idea..

Kerry Chadderton

I agree. I just ordered everything this morning to replace the whole system, top to bottom. I've spent so much money on DME, Clutch, Timing Belt, Wheel bearings, Brakes, etc, etc ,etc. $160 ain't gonna make a difference now!

What really confused me on this was that there is zero, I mean ZERO leakage on any part...externally. And ZERO loss of fluid over time. I've had slaves and masters fail before, but they always showed some sort of leak. Usually into the bellhousing or behind the carpet on the firewall.

Oh well, on to the next adventure!!!

Thanks again for chiming in everyone!

fittrjoe

+1 on the line to slave swap.
did as prescribed , bleed from above. fish it back down, done.
thats why they call them " high point vents " in piping systems, air rises.
motive power bleeder for sure , any way you go.

Kerry Chadderton

It was the little check valve at the spring end of the M/C piston! Rusted like nobody's business! I put a new piston in and everything is merry again!

Thanks for the help!

944Ross

Fluid must have been "wet", flush well! Congrats!

yellowline

Bavarian Autosport sells this little tool for $25. Bench bleeder for clutch cylinders, works with a pressure bleeder. Haven't looked into how effective it is.