I'm bringing my old 86 2M4 out of retirement. It's been sitting for a few years but I was driving it once a month around the block a few time to keep things from seizing up. About a year ago I had to stop driving it because the clutch pedal went strait to the floor. It's as if it is no longer connected to anything. I was wondering if anyone knows a way I could diagnose the source of the problem. Is it the slave, the master, a linkage I could check. I was a bit more familiar with my fiero when it was last on the road. I'm thinking I'll need a new master cylinder anyways as I cannot open the resevoir. The cap seems to have bonded to the plastic base.
I suspect now that it is the master cylinder. I was really trying to wrench the cap off the reservoir when I put it into storage to check the fluid. I think I probably cracked the plastic and let air into the system. I got a new Rodney Dickman Master Cylinder on the way which should at the very least give me a reservoir that I can open. I am thinking the slave is okay, because the full pedal movement still seems to move the slave ever so slightly. If the slave is damaged beyond a rebuild kit then it isn't going to get fixed (because I plan an ecotec swap with trans anyways)
I recently successfully went through a similar clutch situation on my 1987 2.8L GT. My clutch pedal went ~50% to the floor, stiffened up, then slowly sank to the floor. I consequently couldn't shift into or out of gear. I bled the system using Archie's guidance (http://www.v8archie.com/v8Archie/home.htm). That worked for ~5 shifts, then the issue was back. I looked for obvious leaks but only found a tiny amount of fluid around the master cylinder shaft. I replaced the master cylinder (~$55) as it's easy to do (took ~30 minutes), but this didn't solve the issue. I popped the boot off the slave cylinder piston. Ahh, there's the problem. Boot was full of fluid (it shouldn't be) that had leaked out of the slave cylinder.
I tried removing the slave cylinder's hydraulic fitting. A 14mm flare wrench only started rounding the hex nut. Nearly daily applications of PB Blaster and light hammer taps for 2 weeks didn't budge this fitting. Propane torch only successfully caught all the brake fluid on fire (apparently brake fluid is flammable!). Finally, I used a die grinder to carefully cut the slave cylinder's hydraulic fitting being careful not to nick the sealing surface on the hydraulic line. I did nick the threads, but as they're not the sealing part, it was ok. Success! The hydraulic fitting came right off. I installed the new slave cylinder while using judicious amounts of anit-seize on all the joints.
I bled the system using just gravity bleed (car on a level floor, keep the master cylinder full of fluid, and let gravity carry the fluid back to the slave cylinder). Afterward, I had a helper work the clutch while I turned the slave cylinder bleed screw, but I literally only got 1 small bubble out. I've read all the horror stories about clutch bleeding, but my experience was great and easy.
If it wasn't for the stupid stuck hydraulic fitting, this whole process would have taken <2 hours. With the fitting, it took ~5 hours.
I spent 10min changing the master and it took me all of 4 hours and 2 bottles of DOT3 before I gave up on bleeding the system. Its been a week and I'm determined to try again. It's acting as if it's puling fresh air in when the pedal retracts but I can't find any leaks anywhere. Slave is dry and seems to have tons of force when I got it retracted with a block of wood. any ideas? I've browsed all the posts on different techniques and the only thing left to try before replacing the slave is to remove the bleed nut completely like Archie suggests. (I read that after I gave up)
What worked for me was just bleed like you would the brakes, then at the slave loosen the bleeder pull the slave rod in then tighten the bleeder before you let go of the rod. Did that once and the clutch has worked great ever since.
We're getting a ridiculous amount of snow for April fools. The car is beside my parents house and I'll give it another shot this coming weekend. Thanks for the suggestions. I'll report back with what works (If anything).