Well hector, just when I am deciding to drive my '85 as a DD the clutch hydraulics are going south. I found the reservoir dry and refilled it, not seeing any apparent leaks but it was getting dark. After pumping the pedal a bunch, it came up fairly well but loses pressure fairly quickly. I guess my question is, ruling out leaks, how can you tell if its the slave or the master thats bad?

 

When my 1990 went bad it never leaked any on the ground. My slave was dumping it in the trans. If your leaking, and it's not on the ground, then I would guess yours is doing the same.

 

I guess I shouldnt try to drive it until I figure it out. Did the bad slave do as I described? I probly need to replace both anyway but money is tight here at Xmas and an A/C Delco master from Rock is about $125. I have read here not to buy a stamped one rather than cast. Anyone know which brands may be cast?

Thanks!

 

Bump. I bought a new slave and master cylinder figuring if one was bad, the other wouldnt be far behind. Any tips for R&R?

 

I think there is a lot of stuff on this, look in the "search" function. The latest recommendation for clutch fluid comes from Bill Boudreau at zfdoc, but probably applies to yours also. He likes Motul RBF 600 racing brake fluid, and is qualified to know.

As for your leak, I agree you should replace both cyls. BTW, a leak from the master sometimes runs down under the carpet in the footwell.

 

The Master leak will be in the cabin....these are notorious for being dry every where outside and then the person finally inspects where the piston and pedal attach and LO! there is the fluid......

Tips on the Slave? Fill the unit the brim and get all the air bubbles out that you can before putting the hose on....then do not turn the unit in a position where air from the hose can get in the body of the slave as you slide it into the bell housing.

Other than the slave/air bubble issue, the rest of the unit is self bleeding with use.

if all else fails while trying to bleed it......you can take the slave out of the bell housing and allow the piston to travel all the way to the end of its capabilities and having someone you trust pump the clutch pedal.....but you cannot push to hard or else the piston will shoot out of the slave and you'll be screwed.

So someone with a soft touch has to push the clutch pedal as you work the bleeder valve.....but this is a last ditch effort and you'll most likely see what I mean once you get to the point of frustration while trying to bleed that Slave.

Other than the bleeding issue, this job is a 4 on a scale of 1-10 (10 being the most difficult) it would be a 2 if the slave was easier to bleed.....

You already discovered how the master can run dry and you just fill it up and pump a few times and it works again.....why brakes can't utilize this technology is beyond me.....but ignoring brakes for now...the Master is easy to bleed but difficult to install

That attachment point is way the Hell up in there and hard to get to. I laid on my back with my head where your feet go and my feet sticking out the top of the car. Not comfortable at all. You have to remove the driver seat cushion and then use towels on the metal frame or else it kills your back...then you need an assistant because you will drop the cir-clip and you won't be able to turn your head in order the relocate it....you assistant has to find it and hand it to you.....

Two things I guess....but in reality it is an easy job.

 

When you install the master cyl, it is easier if you can get the car off the ground. I have a lift, but you can put the car on stands, makes it less unpleasant.

 

^^Lift the car for the Master??? I'm not sure I understand.

Slave??? absolutely....jack the car up......but Master?

 

If you raise the car, you can sit on the ground to work on it, rather than drape yourself in thru the door. Trust me, it's 'way better.

 

Well half is done. The master is in. Tomorrow the car gets put on stands and the slave goes in.

J- I definitely see what you are talking about. After taking the hush panels off I still had a helluva time even seeing the clip. I actually havent tried to reinstall the clip yet so I may still be doing the upside down thing. I will have the car on stands tomorrow so I hope Steve is right about being easier with it up. Dunno if youve seen recent posts about the aftermarket door locks I have but all the control modules were zip tied to the wiring and in my sight path there. This is gonna definately "while I am in there" deal where maybe I can knock off about three problems before I button it back up. You know I still have not addressed the ground issue on my dash lights yet...........lol. The Vette hasnt been my DD so it wasnt at the top of the list. Things change tho. And yeah there was fluid all at the back of the cylinder and all over the rod.

As for bleeding I bought a cheapie vac pump from Harbor Freight and I am hoping that will take care of all the bleeding problems with the slave. After I get done and if it does a good job with the clutch I am gonna change out the brake fluid as well.

 

Steve, I'll look at it next time

The issue with "while your there" is with me anyways cause I'm getting older.......I couldn't stay upside down for more than about 20 minutes without getting a headache.

 

Well Steve is right, you can SEE the pin better, lol. I still cant get to it any better. The hole in the master rod is machined so closely I cant get it on the clutch pedal pin. Its cocked sideways a little. Looks like I will hafta loosen the MC some to get the small amount of torque on it to get the rod centered on the pin. I hate that as I took the battery out to reach the lower MC bolt and really hate doing chit twice

The little vac pump seems to work ok as well. The little adapters included wouldnt stay on very well but the tubing slipped right over the bleeder knobbie. I got great amounts of air out as well as fluid. I think there is a little air slipping around the bleeder screw threads so I may put a twist or two of thread tape on em to get a better seal.

I took off today to finish but since its about 35 here in FL, I am moving like a turtle. The sun is finally out and I am hoping the wind will die down. I dont know how them dam yankees do it, lol.

 

You should treat yourself to an extra-long pair of long-nose pliers. It should not be necessary to loosen the cyl to install the pushrod.

 

You would think this would be the case Steve but I have managed to grab it with channelocks and havent been able to get it on. Ive even managed to grab the eye and the clutch pedal and tried to pinch it on. Even managed to hit it a few times without changing anything. This is the reason I hate working on things because the weirdest problems on the simplest stuff occurs when I do. I am prepared for this to happen, it doesnt upset me anymore I just accept its gonna take me twice as long to do anything.

 

Guess I don't have an answer for you- I have changed this cyl more than once (don't ask) and always, with a little perseverance, got the linkage hooked up with the cyl bolted up tight.

 

FINALLY!!! Jeez I dont know why it takes me so much longer than the average guy on any mechanical project. I found the MC push rod was bent and in my efforts to squeeze the eye onto the clutch pedal, I managed to scar the inside of the eye pretty well. Dunno if I bent the rod or it came that way but I straightened it out then dremeled the eye out enough for it to slide over the pin easily. I dont know who designed the dremel but I would kiss them full on the lips cuz that tool is neater than sliced bread. I also have to give kudos out to Harbor Freight for the cheap little vacuum pump they sell eliminating the need for that second person to bleed hydraulics. With the pump there is no need to prefill or bench bleed the slave or MC. It may take less effort if you do but you dont have to.

I didnt get to the "while I am in there"s yet so I am leaving the hush panels off for now. I did manage to change the oil and filter while it was up on jacks. Hopefully more to follow next weekend if its nice. Now its time to

 

^^I hated the clip as well...it was difficult to clip on...

good job getting it done