Help me diagnose clutch master/slave cylinder issue
 

Installed a new clutch master and slave cylinder and have had a hell of a time trying to bleed it. I say that because I have about an inch of fairly mushy pedal travel after the pedal piston contacts the master cylinder.

One thing I've tried doing is burping the slave cylinder from underneath the car (pushing the plunger in by hand with the reservoir open). I've noticed that the slave cylinder is not returning on its own (spring power) but only if I go in and pump up the clutch again.

Is this normal?

Bleeding the whole system is a bitch. The only thing i have found that helps having done it a few times is that I installed a speed bleeder on the clutch slave. Other than that you just need to follow the procedure in the FSM and be very patient.

Oh the thread pitch for the slave is M7 x 1.0. i don't recall which speed bleeder I used exactly but you can search by the thread pitch.

Thanks for following up! Interestingly, I just removed the speedbleeder you mention because I got so fed up that I decided to rig up a reverse bleed setup. I pumped almost an entire bottle of brake fluid through the slave bleeder valve and then tightened it. I left the reservoir cap off and went to pump the clutch to see how it felt. Nothing. The master cylinder didn't have any charge clearly.

So, I opened the bleeder back up, pulled the hose off the reservoir (connecting to the clutch master), and forcefully injected about 50cc of fluid into the master with a syringe.

Tightened the bleeder back up and pumped the clutch. This time it worked. I still do have about 1/2" of mushier pedal travel (post free play) before the clutch gets nice and heavy.

One thing I've noticed is that in it's fully-compressed state, the (OEM) slave's rod has a fair bit of play (maybe 1/2", didn't measure) with the arm on the clutch. This normal?

Any thoughts on all of this? I'm so tired of hydraulics!

I wonder if Hinson would make us a version of this for our cars:
HINSON Corvette Remote Clutch Speed Bleeder Line C6 & C6 Z06 Corvette
Sure would make bleeding the clutch easier. Not sure it's $50 easier, but maybe.

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One of the JDM companies makes one for our car but it's rare and $$$$. I tried to put together one myself but with available parts I was not able to do it due to the M7 x 1.0 thread pitch.

It wouldn't be very difficult at all to make one if you had a tap and die and drill press. Great idea wankelbolt

I have a set of these which makes life easier. http://www.gearwrench.com/wrenches/r...et-metric.html

You would have to drill out the slave and the conical part at the bottom is what worried me about drilling it to a more commonly used thread pitch. It could definitely be done.

Update: so i'm confident this system is bled. Bled it from all angles (literally), using pressure, vacuum, pedal pumping, speed bleeders, traditional bleed screws, and gravity. There is no air in the system. Right now the pedal is 'softer' for approximately 1/8" of master cylinder piston travel. I have read that this is a pretty good result.

Anyway, with the air bled, I continued to experience hard shifting. The pedal play on the new master cylinder was within spec, so I lengthened the travel (lengthening the pushrod length as well to compensate of course). I'd estimate I added .75" of travel at the pedal. Interestingly, the master cylinder piston is still far from bottoming out in the bore. I'm curious whether this is the same as an OEM master cylinder (mine is Beck Arnley, probably should have gone OEM. went OEM on the slave).

End result is significantly higher engagement point obviously, but also easier/smoother shifts. I'm temped to increase the travel even a bit more, but don't want to overdo it and (possibly?) bend the throw out lever. Don't know if this is something to worry about? Just to mention, there is no noise or unusual resistance when the clutch is fully depressed at idle.

Anyone know if the master cylinder is supposed travel the entire bore? Any thoughts on what I've done?

Did you look at the FSM procedure for the adjustment?

http://foxed.ca/rx7manual/2003mazdar..._S01_0498.html

I did but i'm certain that i'd be out of spec now (longer travel). Clutch is now about half an inch higher than the brake pedal. So i'm adjusting based off ability to fully disengage clutch with my new master/slave, not specs.