indefactorX

I think my master cylinder has had it's last shift earlier today

The problem just started today, My clutch pedal is getting stuck when it is depressed all the way, and some times even just half the way in,

I checked around the clucth cylinder and i noticed that alot of fluid has leaked out around the rubber seal and into the carpet

Another problem i noticed and i'm not sure if this relates to the clutch, but just above the clutch pedal to the left is a tank that looks like 3 transparent sphere's fused together, This tank is empty and i'm not sure if this is the clutch fluid or the power stearing fluid

Please if anyone can help or recomend a solution or point me to a rebuild kit,

I called 928intl and spoke with tom and he told me the replacement part would be 75$ but if there is a way around this i would be willing to take it

G Man

Not sure but the three spheres sounds like some type of vacume resivour. That's my two cents worth.

Andrew Schauer

I am fairly certain the 1979 master cylinder is the same as the 1980, and there is a rebuild kit available:

Clutch Master Rebuild Kit
Raybestos CMK1899

It can be a pain to crawl under the dash, but it is possible without removing the cylinder. If the bore is still smooth, and it's only the rubber seals which are the problem, it's definitely worth a shot. ~$25.00 if i recall correctly.
Bleeding the clutch is a whole different ballgame...

GlenL

Search for instructions on re-building the master from inside the car.

The unit itself bolts up from the engine side of the firewall. I replaced the whole thing and it was a PITA...with the engine out!

User 4221

You WILL want to rebuild with the cylinder installed for two reasons:

1) It's a PITA. I had to R&R mine 3 times. (See #2)
2) The cylinder I bought (Genuine Porsche) was not compatible with the slave. Translated: The fluid volume displaced by the new master was less than then old master. Thus, the slave could not move through its travel range.

Finally I rebuilt the original, re-installed it, and all was well.

Good luck.
Scott

indefactorX

where do i get the fluid that drained out?? Because i'm preaty sure the cylinder is running dry


And does anyone have any ideas of what that tank is for, the transparent tank that looks like three fuzed spheres....


also i think i'm out of power steering fluid but i have no idea which cap is for the power stearing, everyhthing is in German

indefactorX

bump

Gretch

On later models the fused spheres you mention are located in the driver side wheel well and are vacuum reservoir.............as previously mentioned.

The fluid leak on the inside of the firewall would come from the master cylinder, where the plunger is sealed to the inside wall of the cylinder. The seal is leaking.

hupp

The tank under the dash is the vacuum reservoir for the door locks. The clutch master fluid is supplied by the brake master reservoir via the "blue hose." In other words, clutch master reservoir and the brake master reservoir are one and the same.

The power steering fluid reservoir is mounted on the drinver's side of the engine bay near the radiator. It's metallic somewhat resembles a small coffee can. Remove the thumb screw and the entire top lifts off. The fill line is stamped into the housing. Automatic transmission fluid is used for power steering. Do not fill with "power steering" fluid, fill with Mercon ATF.

WallyP

In the engine compartment, directly in front of the driver's seat, is a large round device, mounted vertically, and partially under the front fender. This is the vacuum brake booster. The brake master cylinder is attached to the front of this booster. On top of the brake master cylinder is a translucent plastic reservoir with a black plastic cap. This is the brake fluid reservoir. The hydraulic clutch shares the fluid reservoir with the brakes. Fill the reservoir close to the bottom of the filler neck using new, high-quality DOT 3 or DOT 4 brake fluid, such as Castrol LMA or Valvoline Synthetic Brake Fluid. Do not use silicone fluid.

The power steering fluid reservoir is at the left front corner of the engine compartment. Use Dexron ATF, not power steering fluid in this reservoir.

You might find this
http://members.rennlist.com/v1uhoh/underthe.htm
interesting. It is an S4, so some things will look different.

Nichols has many, many useful tips on the 928, and some clutch tips are here
http://www.nichols.nu/cat10.htm

I would suggest that you contact Jim Morehouse and buy the 928 tech info CD set that he has prepared. The set includes a HUGE amount of tech info. Jim's email address is
jim928@ptd.net

indefactorX

alright guys, i got the new master cylinder from 928 intl and pulled out the old internals from the existing master cylinder and slid in the new ones, i have a problem though, I can't get the thing to bleed, is it a good idea to pull the plunger in the master cylinder out a little bit to get fluid into the cylinder???

Any other help or ideas are apreciated

MikeN

Unmount the slave cylinder and push its rod in a few times.......this is the only way I have ever gotten the dang things to bleed properly.......good luck.....

indefactorX

sounds like a good idea, wish i could do it right now but it's raining

do i do this with the nipple off of the slave cylinder?

User 4221

Do a search on clutch bleeding. WallyP has a great writeup on this.

Or, go to www.nichols.nu/tips.htm and search there.

HTH,
Scott

MikeN

You do this with all the fluid connections made/tight/closed. Just unmount the slave and carefully move it back till you can freely move the rod back. Do it a few times and you can almost feel the diff as the air gets pushed out of the system. Make sure you mount it back securely with the rod in the release arm
indent before trying the clutch pedal again.