I just replaced the clutch master cylinder on my wife's '86 2M4 5-speed. I seem to remember it took quite a while to get the clutch bled when we did the same to her '84 4-speed, but now I'm wondering if the new master cylinder is defective. Yeah, we're still getting bunches of air out of the bleeder screw, but not as much fluid as it seems like there should be. Plus, on the recovery, it doesn't seem to pull much fluid out of the reservoir. Maybe that's normal? Without a check valve AND with tons of air still in the line? HELP! I have an appointment to get it aligned Wednesday and I would really like to keep it! Thanks in advance - Chris
Why did you replace the MC? Did the clutch start to drag, causing it to be tough to get in gear from neutral with the clutch pushed all the way in? From my experience it is seldom the fault of the MC. Usually it is a pitted slave cylinder causing air to get in the line or a pin hole in the line somewhere. Either of those problems will make it impossible to get a good bleed. And in the case of a pitted slave cylinder, most of the time you will not see a leak.
I do not remember how long it has been since I replace a slave cylinder. I put a stainless steel clutch line on the last time I replaced the slave and have never had a problem since. The stock steel lines rust on the inside and cause the leaks and the pitting of the slave cylinder.
------------------ 86 GT built 2.2 ecotec turbo rear SLA suspension QA1 coilovers on tube arms
Thanks, wftb. Master cylinder fell all the way to the floor and just barely released the clutch enough to shift. Disassembly of the old unit revealed leakage out the back of the cylinder due to a worn rear seal on the piston. It occurs to me now that I might be able to disconnect the hose from the slave, get the line and hose purged, then reconnect and bleed the slave. Thoughts? TIA, as always - Chris
Give it a try, but take the slave apart and check for pitting while you are at it. The other thing is that bleeding these things takes a while it isnt easy. I use a length of 2x4 to push the clutch pedal with and a speed bleeder on the slave cylinder. That way I can watch how much the slave rod is moving. If it does'nt come out about 1 1/4" it wont give you the pedal travel you need. And there are other methods like jacking up the rear with the bleed screw open to get the air out. Search is your friend as they say. Good luck with it hope you get it right.
Assuming that there are no leaks in the system and the brake pedal isn't bent, I've had good luck bleeding the clutch hydraulic system, with the Mityvac hand held brake bleeder. You apply vacuum then open the bleeder screw let some fluid flow out and close it before you lose the vacuum. Do this a few times and you are good to go.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Thanks, everyone. I was loaned a hend-held vacuum bleeder today, and used it as soon as I got home. It worked pretty good, and for a second it looked like I had pretty close to the 1-1/4 inch travel I was hoping for. Then it all went away. Going to try once more in the morning with grease on the bleeder screw threads and the left rear jacked up. BTW, where is anyone/everyone sourcing replacement braided stainless slave hoses?
While doing a little investigative work and robbing my GT of its slave cylinder, it appears the clutch hard line and slave end hose are a one-piece affair. Saw where RD is asking almost 2 bills for a new one. Wonder how hard it would be to cut off the old stainless end and plumb in a Russell hose. Additionally, the slave out of the GT is poop - rusty, crusty bore and one mounting ear broken off. I suspect I'm going to find the SE's in the same shape. Guess I'm breaking out the checkbook again. Rodney, here I come! More as it happens - Chris
Another alternative is a new stainless steel line from the Fiero Store. The old lines corrode on the inside and turn the fluid brown, the only stainless part on the old lines is the flex lines at the ends. And even if you put a new flex end on your old line a hole will eventually just develop somewhere else. Unless your car has never seen salt.
I put on a stainless line on my car I think 6 years ago and have not had a slave cylinder go bad since. I used to have to replace the slave every year.
[This message has been edited by wftb (edited 10-21-2020).]
Thanks, everyone. I was loaned a hend-held vacuum bleeder today, and used it as soon as I got home. It worked pretty good, and for a second it looked like I had pretty close to the 1-1/4 inch travel I was hoping for. Then it all went away. Going to try once more in the morning with grease on the bleeder screw threads and the left rear jacked up. BTW, where is anyone/everyone sourcing replacement braided stainless slave hoses?
Here's an additional step to consider....after bleeding the system, whether gravity or vacuum, and everything feels close but maybe not perfect, use both hands to pull the slave cylinder rod back into the slave cylinder a quarter inch or so (but no further) and have someone briefly crack open the bleeder valve and close it before you release your hand pressure on the rod. Then refill the master as needed.
This has helped me purge those occasional last, stubborn pockets of air out of the slave cylinder. Works great.
As i suspected, the slave cylinder on the SE was krap. Rust throughout the bore, seal skirt worn to nothing, fluid in the bore on the back side of the seal... Good thing I've got a fresh one coming! I just really hope this takes care of the problem. Should know on Sunday.
I recently replaced my clutch MC, line, and slave cylinder. All from Rodney Dickman. Correction; the line is from the Fiero Store. Installation was pretty straightforward. The line is in 5 sections. My only complaint: things would have been much easier if the front flex line was longer placing the unions in more accessible locations. Anyway, when it came to the slave, I hooked it up but did not bolt in. I just had it laying in place with the rod pointing nearly straight downward. I did this instead raising the driver's side. Now when I pumped the clutch, the fluid will fill the cylinder before wanting to go out the bleed screw. I was also able to push the rod in to be sure air was bled. After doing this I bolted the cylinder in place. The system feels nice. Good pedal. Unfortunately due to other ongoing repairs, I haven't been able to road test it yet.
My Son helped me bleed the cylinder. He would press the clutch in and hold. No pumping like with brakes. Rinse and repeat. Of course I first bench bled the master cylinder. The MC doesn't hold a lot of fluid. I refilled after a few pumps several times. Didn't want to chance the MC sucking air. It took awhile, but not what I'd say was a long time.
------------------ Stanton '88 Formula, red on gray
