Yes, I'm doing a search, but there are a LOT of clutch hydraulic threads, and I'm wading through them. Thought it might be faster to post a new question.

The car is an 88 Formula 5-speed (Getrag) - all stock.
Everything works fine and no changes have been made to the car in over a year, but I've started getting air in my slave cylinder. I see no visible leaks and no discernible fluid loss. I can take 2 minutes and bleed the slave cylinder using Archie's method* and everything works great, until I get air in the system again. It used to be only every few months. Then every few weeks. It's getting worse and worse.

I saw the recent thread about early style clutch master cylinders and how they can cause this kind of problem, but mine is a different design. Does anyone know if it's the same problem? I have a replacement slave, but it's cast iron and I've still got the OEM steel one on the car. I'd like to keep the steel one as long as possible. Possible master cylinder problem? Suggestions?


*Slave Bleeding Method:
-uncap master cylinder
-completely remove slave cylinder bleeder screw
-push in slave cylinder pushrod (you will see air bubbles coming out)
-reinstall bleeder screw while holding in pushrod
-slowly release pushrod to let it pull fluid from the master cylinder reservoir
-top off master cylinder and recap

I can do the whole thing in a couple minutes and only need to do it once to restore full pedal. I've never had to bleed the rest of the system by pressing the clutch pedal. If air is coming in from somewhere else - it's making it's way through the system and collecting in the slave cylinder.

If you looked up my post on clutch masters and yours has the line off the end of the master, yes it can have the problem also.


As I said, any fluid that leaks back to the resivoir will cause air to be drawn in.
If your not loosing any fluid and there is no leakage in the slave dust seal it can only be the master.....

[This message has been edited by Dodgerunner (edited 05-15-2007).]

Thanks! Kinda what I expected, but was looking for a second opinion before popping for a new master cylinder.

-Technical Discussion & Questions: Reason 37 for why PFF rocks.

You might see if you can find a rebuild kit. They are not hard to do and your type of master only has three parts. (two seals and a dust cap) A kit should be about $20. I just bought one for the other model which I have and it cost $23. A lot less than I can get a rebuilt master for.

I'll check it out. Rockauto has a Raybestos master cylinder for $64.89, and a Dorman rebuild kit for $38.79. I'll check around and see what I can find. It's no rush yet. The slave bleeding is just an inconvenience so far. I just want to fix it before it gets too bad.

I just checked my Oreily's and they had the cardone brand reman for $24. surprised me..

In my experience, air getting into the slave is usually only the master's fault if the reservoir runs so dry as to actually pump air into the line. If your reservoir is constantly running low or leaking, then it needs a rebuild.

If small amounts of air come into the front of the system, it will rise into the reservoir. It takes a large amount of air to get shoved far enough down the line to begin rising into the slave all the way from the master.

For me, problems with air in the slave (other than the above) have always been in the rear half of the system.

If you haven't figured it out by this weekend, F88, I'll be happy to come help... I use Archie's bleeding method with a modification when I bleed mine. It takes a couple minutes of patience, but I feel more secure knowing that air isn't getting sucked back into the slave past the bleed screw upon release of the rod.

------------------
Patrick W. Heinske -- LZeitgeist@aol.com
1988 Red Fiero Formula Convertible
*Desktop Photo Here* (click either link for pics)

I packed the slave cylinder boot and the outside part of the piston with grease like previous postings, and for the first time my bleeding seems to hold. It's been three weeks with a good clutch on my 88 GT.

I could be wrong but I think that proves my statement that a failing master will suck air in from where ever it can.

By packing grease in the outer part of the slave your blocking the air from pulling in past the seal.

Still think the root cause is the master losing fluid back to the reservoir then over time the air build up in the slave.

The grease is masking the real problem.
May last a while but if the leakage gets worse in the master or the grease melts out your going to start to see it again in the future.

[This message has been edited by Dodgerunner (edited 05-16-2007).]

I feel your pain. I've been dealing with this issue for over a year now. I've replaced all the hydraulics, both cylinders and line. Both cylinders are OEM, clutch line is aftermarket. I got the master off ebay from some guy that usually sells mazda parts but he had a few OEM NIB Fiero master cylinders. Got it dirt cheap too!. In my attempts at bleeding I seem to get air in the line.Tiny bubbles actually appear to come from the bottom of the resivoir on the master and a lot of bubbles in the bleed line at the slave end. I noticed that around the center of the fitting that screws into the master cylinder that there was fluid pooling around where the tube comes out. At this point I figure that my aftermmarket clutchline is leaking around one or more of the fittings. I wish I knew someway to test this besides seeing fluid leaking. I have not been impressed with aftermarket parts in the least. And I think rebuilding an OEM is still the best option though the parts that you rebuild it with might be subpar too.