clutch slave cylinder.. do master at the same time?

[Obin Robinson]

ok, right as we were pulling into the driveway after the Porsche swap, the clutch pedal dropped to the floor. i think the slave cylinder needs to be bled, but i'm thinking of replacing it.

should i replace the master at the same time? how long does it take to replace the slave cylinder and bleed it, with an assistant?

any tips?

thanks!

obin

[rben]

Obin, the slave cylinder is easy to replace. It will require removal of the starter. The master cylinder is a lot harder to replace. If the master cylinder is ok, just do the slave. You can save some money by purchasing a rebuild kit for the slave cylinder. I don`t know if Wayne sells the rebuild kits. If not it might be a good idea to do so. most of the supply houses want to sell a you a new part instead of a rebuild kit. The tough part of the job is bleeding the system. I have done the slave cylinder on two different cars and tried several things to get darn thing bled. The last time I found a post that suggested using a oil squirt can, filled with brake fluid, and a short plastic hose to pump the fluid in at the bleed nipple. It works great. Good luck
Ralph

[Obin Robinson]

thanks!

also, i'm wondering... any way to tell if it's just air or not? i didn't see any rebuild kits for the slave cylinder on Pelican Parts site. i don't want to replace the salve cylinder if it's not necessary, and i don't want to bleed the system only to find out it was the salve cylinder... AND i don't want to order each cylinder separately!

but, for now, i'll just bleed the system. the starter isn't too hard to pop out is it? it's easy on the 924.

thanks again!

obin

[stray15]

If I were you I would replace both at the same time. They have a tendancy to go back one then the other. I've replaced both master and slave twice already because of faulty parts.

The starter is real easy to get off, just 2 bolts, besides the ones holding the wires. I would say an hour job for each. It was nice to meet you this weekend Obin.

Tim

[rben]

I doubt if air in the system is the problem. If your clutch pedal dropped to the floor it is probably the master or the slave. Once you get under your car you should be able to tell where the fluid is leaking. I never had to replace the slave on my 924, but it is probably the same as a 944.
Ralph

[951carter]

It's a snap and the parts are cheap. Besides, doesn't it just feel good when you put new stuff on the ol' P car!?

[stray15]

Originally posted by 951carter
doesn't it just feel good when you put new stuff on the ol' P car!?

I have to agree with that!

[Dave951M]

If you do one that is faulty, odds are that the other will not be far behind. Change both and head future trouble off. The other may not fail ever, then again, you might not make it 10 miles before it goes. If it's just air in the system, then it had to come in from somewhere, again pointing to something amiss at either end.

Dave

[1.2gees]

Obin, I have a master and slave cylinder both of which worked at time of removal (two weeks ago). They're both 2 years old. I'd give them to you cheap. But if I were you I'd just try bleeding it first. You cannot really bleed the master, all you do is pump. Contorary to what everybody seems to say, I think it's quite easy to do.
Ahmet

[maachan]

Hi,

My '87 924S had the clutch pedal gone to the floor in March 2000. The pedal stayed there till I manualy pull it up. I then tried the pedal and guess what I have never had the problem since then.

The car was purchased in October 1999. It was in sad condition. The hydrolic fluid's color was black!! The reservior had a lot of sludge build up. I spent sometime to clean it and blead the system.

My guess to what happen to the clutch in March 2000 is due to sludge became free floater in the system. Then it got cought in the piston which act as one way check valve as the pedal is depressed, thereby not building pressure to actuate slave cylinder. Once the pedal was pulled by hand the entrapped free floater became free again.

Since the color of the fluid turned tan, I flushed the system again in October 2001. Like I said I have not had same problem again.

If the fluid level was kept and there is no external leak, there is little chance of air entering in the system. You may have the same problem like I had.

Good luck,
Maachan

[Obin Robinson]

Originally posted by 1.2gees
Obin, I have a master and slave cylinder both of which worked at time of removal (two weeks ago). They're both 2 years old. I'd give them to you cheap. But if I were you I'd just try bleeding it first. You cannot really bleed the master, all you do is pump. Contorary to what everybody seems to say, I think it's quite easy to do.
Ahmet

Ahmet,

thanks! but damn i already ordered then on monday afternoon . oh well, any tips to replace them? do i need to put the entire car on jackstands, or just the front?

thanks!

obin

[Bob's944]

I did mine with just the front jacked up. I also had a very very very ..... difficult time getting it to bleed the traditional manual way(took over 24hrs with breaks from the bleeding to keep from screaming my head off, or ripping something off the car, or... u get the picture). Some people have mentioned that they felt having the front end of the car higher than the rear was the reason why it took so long. Maybe you can find out if it's true or not. If you have a bleeding sys, use it.

As far as tips.... use flare wrenches on the fittings to prevent stripping them .... if you have A/C, you'll need a good socket swivel attachment to get at the master cyl's back mounting nut, I also needed a snake to get a a nut on the cover you need to remove to get at where the master cyl attaches to the clutch pedal.... make sure you close off the feeder line coming from the reservoir, vice grips work..... i took a pic of all the vacume hoses you have to disassemble to get at the master cyl just in case I couldn't put them back right, here's that pic if you need it....

[divezic]

Obin,
If it went to the floor and stayed there then you blew a seal in one of your cylinders. It isn't just a little air in the system. Replace them both. I lost my Slave and the master blew about 4 months later. Do em both now and save the time and aggrivation.
Piece of cake on the Master and Slave. I did my slave in about an hour, including bleeding. Master cylinder was changed in the parking garage by my job with simple tools in about an hour and a half. It was tough to get at the master cylinder's bolts but it wasn't that difficult. Special tools that Bob mentioned could make it easier.

-Jack up front end
-Remove starter
-Remove hydraulic line
-Remove slave cylinder (2 bolts I think)
-Replacement really is the reverse of removal except for the bleding. Either do it with the Mity Vac, pressure bleeder, or by the tried-and-true way of having somebody work the pedal up and down with you under it opening and closing the bleed valve. Any way you choose it's just like bleeding your brakes. I used the Mity Vac solo and they bled completely in about 20 minutes of squeezing and refilling the reservoir.

Master cylinder
-Clamp off the fluid feed line.
-Remove hydarulic line.
-Remove the two bolts that hold the masrer cylinder to the firewall.
-Slide out the master cylinder.
-Slide the new one onto the old actuating arm if the old arm is not too coroded. If you want to use the new arm then you have to go upside-down under the dash and remove it. Not difficult just a squeeze.
-Repalcement is the reverse of removal.
-Bleed.

If you do the master and clutch at the same time, you obviously do only one bleed at the end.

[1.2gees]

Well yes actually...

I unbolted my slave cylinder off the car (actually this was the new one so it had never been on in the first place), tilt it so that the bleeder valve is above the fluid line going into the cylinder. Traditionally bleed for about 2 min., pump the pedal a few times, and repeat once. I was done in about 15 minutes. Sometimes letting a car sit with the bleeder valve slightly open overnight can help. Or a pump that pressurizes the master cylinder.
Ahmet

[Obin Robinson]

ok, thanks everyone for all the help! we got the master and slve in saturday afternoon. the slave was so damn easy that i think that if anyone pays to get that done.. you are majorly wasting your cash. it was damn simple. two bolts, two wires, then two more bolts and a hose and it was outta there!

the master was only tougher because of the angles. only unded one vacuum hose, had to rotate the master 90 degrees SIDEWAYS to get it out easy. reinstall was damn simple. the ONLY part that was a ***** was bleeding it. don't even get me started on that one. lots of help from my wife, along with an entire container of Valvoline Synthetic brake fluid.

what was wrong with the old stuff? well, the seals were all crumbled. they looked nasty after 18 years of usage. also, the fluid in them looked like TAR! it was gooey, thick, and sludgy. the stuff we purged out of the system looked like dark coffee!!!

the new fluid was refreshing, crystal clear like Perrier. mityvac, and LOTS of refills to the clutch master cylinder did it.

the difference? WOW WOW WOW WOW WOW!!!! the 944 clutch feel is so light yet precise! if i knew that it would feel this good and different, i would have done this a LONG time ago. driving the car now must fell like what it did for the guy that rolled it off the assembly line. superb clutch feel. before it was like squashing down on one of the pedals on an exercise bike. now it's almost effortless!

we didn't jack the car up offhand, just used our "Rhino Ramps" that allowed for all the access we needed.

thanks again everyone!

obin

[Obin Robinson]

forgot to add, for all people that do this in the future:

using Bob's pic (thanks bob) here's the bolts that we undid and got all the access we needed to the master quite easily:

the ones that are circled are what we unbolted. also, the clamp i circled was the only vacuum hose that was undone.

thanks again!

obin