Clutch master and slave cylinder replacement in Houston

[ammrpm]

Any of you Houston guys had to replace the clutch master and slave cylinder recently?

It looks like I may have a leak at the slave cylinder. I don't see a leak around the slave itself. I see a small drip of fluid where the transmission mates to the bellhousing at the lowest point. The fluid in the master is low as well. I am assuming that the end seal of the slave has failed and is allowing some fluid to leak into the bellhousing area. I will know for sure when I remove it.

Any tips, tricks or advice anyone can provide on changing these things? I think I am gonna replace the master and slave at the same time.

Thanks!

[gbrtng]

The slave in my 91 has always leaked a little but not enough to bother with replacing it. I just check the fluid level in the master every 1000 miles or so and add when necessary. Got stranded once with no clutch action at all and discovered no fluid in the master. That was when the car had about 10,000 miles and I didn't know it leaked. So I improvised and borrowed some fluid from the brake master cylinder to get it home.

[Z51JEFF]

Not from Houston but I did replace the Slave about 6 months ago.Took forever to bleed the system.Finally used my Mityvac to force fluid up through the slave to the master.Lots of info here when the time comes.

[pantera1683]

When I first got my car I wanted to replace all the fluids, so I bled the clutch fluid through the slave with a mityvac pump and it worked fine.

A few weeks later I upgraded the brakes and installed a brake bias spring in the master cylinder. It required me to remove the master from the car to install. After I reinstalled it, I bled the master with a plastic kit from one of the auto parts stores. I threaded the plastic nipples into the side ports, filled the master with fluid and attached the vacuum tubes to the nipples. I placed the other side of the vacuum tubes into the brake fluid, pumped the brakes a few times to get all the air out of the master, removed the tubes and nipples, attached the brake lines, bled the slave with the pump and I was done.

All-in-all, it was pretty easy.

Good luck.

[tomtom72]

I would just mention that if yours is a 90? Buy the 91 & up line from the master to the slave. The early line, 89 & 90, doesn't fit well on the new slave cylinders. You have to adjust it a bit to fit. If yours is not a 90 then you are good to go parts wise.

A quick suggestion on method: gill panel off, battery out, and the clutch master cylinder's nuts are easy. You don't have to do this extra work, but it makes getting on the clutch master cylinder nuts easier.:thumbsup:

:cheers:
Tom

[rhipsher]

PM sent.

[Kb7tif]

I replaced both master and slave same time, was pretty much uneventful and simple and should be or something is wrong. PM sent.
Take the drivers seat out.

[ammrpm]

Quick update...

I am about half way thru this project. I have removed and replaced the master. I have removed the old slave and called it quits for the night. I will try to get to the rest tomorrow or over the weekend. I think the hard part is going to be getting all the air out of the system, but we will see. I have a mityvac I am going to use to reverse bleed the system by pushing fluid into the slave and up to the master.

Thanks for all the advice and comments!

[QB93Z]

I have never had a problem bleeding the air out of the clutch system. Here are a couple of tips:

1 "Fill" the slave with fluid before you install it. I do this by putting the slave cylinder in the vise and push in the piston (against spring force). Then slowly let the piston travel out while adding fluid at the tubing connection. (a small funnel helps). You don't need to have it 100% full because when you install it, the piston is pushed inward by the clutch fork.

2. Attach the line to the slave before you install the slave to the bell housing. Then when you push the slave against the clutch fork, the fluid displaced by the piston inward movement will fill the line and the master cylinder.

3. When you operate the clutch pedal to get any remaining air out of the line, DO NOT install the master clyinder seal cup and/or cap.

Good luck.

Jim

[rhipsher]

Two words. Reverse bleed.

[ammrpm]

Reverse bleed the system. It worked like a charm. I tried my mityvac first, but it just could not apply enough pressure to force fluid through the system. After talking with Rick, he told me to try a big syringe to force the fluid up through the system. Well I got out a big syringe that is mainly used to measure and mix gasoline. I believe it is called a mixmizer. Filled it full of 50 cc of clutch fluid and forced it right through the bleeder valve up to the cup on the master. I had a clutch pedal in 5 minutes.

Thanks for all the advice everyone!

Aaron

[Kb7tif]

Heres How I did mine, with advice from a person who changed several.
Replace master and slave. Open bleedvalve on slave. Pour fluid into new master. Let fluid pour thru system and catch excess in container. Close bleed screw on master. Now this is the way I did it.
Open drivers side window. Use a Peice of wood or baseball bat to depress the clutch peddel while watching the clutch master. Watch the fluid for very small bubbles comming to the top while depressing the clutch peddel for only the first 1-2 inches of travel. Push down let bubbles escape release and repeat. Will take a bit 5-10 mins. The peddel show come right up and mine was 80% stiff. A few full depresses at full travel with the foot and I had A ROCK solid peddel. No Mighty Vac, no pumping the hell out of the peddel ect. Have fun.

[ammrpm]

Well, I finished putting everything back together and took the car out for a spin. The car seems to shift through all of the gears just fine, both at low and high rpms. One observation though, the clutch seems to engage just a little sooner than it did before. Don't know if this is just because of the different master and slave combination or if it may still have some air in the line.

One other thing I noticed as well... the new master did not come with a moisture barrier. I tried to put the one from the original master into the new one, but it does not quite fit and the cap will not close with it in there. So I just left it out. Does anyone think this will cause a problem? The cap on the new master does seem to have some kind of rubber seal at the top, but it definitely does not have something that sticks down into the reservoir like the original one. Just so you know the new master is a cast unit that was bought from Advance Auto.

[tomtom72]

Yea, talk about saving a nickle! The new cast masters don't come with that barrier unless you bought a DOM type from GM. I'm not even sure that GM sells our parts as they did go NLA back when they had quality control issues.

I suck out the fluid in the master when it starts to look cloudy and pour in fresh stuff, repeat a few times till it looks better after driving. Or you can just do another reverse bleed when it gets cloudy. It usually takes me a few weeks to get most of the cloudy stuff out and the get the fluid to remain fairly clear again.

Oh, up top on the 'start to feel the clutch' point is that what you are finding? I'm not 100% sure but mine is the same way. I think that's correct.

:cheers:
Tom