Gall757
OK, success!! Extended slave push rod solved the problem.
In review, in order to put all the actions taken and results from that action I will list them and further refer to them by that number;
1. Changed slave. This cured a previous '87 V6 and a Suzuki Sidekick I once owned with exactly the same symptoms. This had no effect. No loss or no gain. I would take this step anyway as two out of three cars it worked. You can buy slaves for $22 or $60.
2. Changed master cylinder. About $60. This actually moved the disengagement point further into the carpet. The flywheel dragged on the clutch when starting and shifting was a chore. The push rod must have been slightly shorter.
3. Bought new clutch peddle from The Fiero Store due to history of faulty peddles from GM ($40 very prompt shipment). It seemed to make the clutch disengagement point even further into the carpet. When I held the OEM '87 peddle along side The Fiero Store peddle before installation, the pins looked like they were close to the same position but not exact. However, I did not make a measurement. Movement of the clutch lever/slave push rod was done at this point as I had read elsewhere in this blog that it must move at least 1.15 inch. Mine moved further. That made me suspect of clutch parts.
4. Towed the car to a repair shop to check out the clutch. The flywheel was cracked and the clutch disk was about down to the minimum thickness. Put in all new parts except used a remanufactured flywheel with no more than .010 removed while CNC resurfacing. There was some discussion whether the hydraulics were fully bled as the disengagement point was no better or worse than when I brought it in after reassembly. Bleeding was consequently done with a pressure bleeder. Car picked up had the same in the carpet disengagement point. No gain. $840. Not please to say the least. Obvious that I had to look further. (Flywheel was on the self at StandardFlywheels.com. The people were great and all worked like clockwork. Had flywheel in two days ($80 + $80 2nd day air freight. Could have been one day for exorbitant air fees.)
5. Installed a Rodney Dickman banjo adjustable push rod ($30 very prompt shipment.) Adjusted it so the peddle was up to metal to metal and down to just bottoming out the piston in the master cylinder if pushed into the carpet. Slight improvement but really not that drivable.
6. The last effort I had little faith in was to make a longer push rod from the slave to the clutch lever. Logic would tell you that the hydraulics is self-indexing as both the master and slave move about the same distance.
1/2" longer was too long. Couldn't get it into the gap with the slave mounting bolts backed off. Made it 3/8" longer and it all went together with a little looseness between the gap due to the piston floating freely in the slave bore once the slave mounting studs/nuts were tight. Not much, though. THIS WORKED LIKE A CHARM.
You need to check for a little free play in the push rod so that when you tighten up the slave mounting nuts/studs, you don't clamp the push rod in the gap between a bottomed out slave piston and the clutch lever arm. I suspect if you do, it will put undue pressure on the throughout bearing and cause early failure. (The moderator can confirm or deny.)
My theory is that the extra compression of the spring in the slave due to the longer push rod moves the clutch lever further from the slave at the resting start point. The slave then needs less movement to push the clutch lever a shorter distance.
It would seem the tolerance build up in the Fiero clutch system leave little margin to work with. With this modification, the disengagement point still seems a little lower than I would expect.
In summary: I would measure the clutch lever arm motion to confirm 1.15+". This blog has some nice photos showing what goes bad on the older peddles. I would then jump to 6 if what your clutch lever movement shows is acceptable and the existing peddle looks good (not bent at the pin), as the bolt was $2.19 for a grade 8 6" long 3/8ths inch bolt. I rounded both ends and sanded them with 600 emery paper.
Your problem might not be the same build up of tolerances. Could be more involved. So take the steps above that seem to fit the details of the symptoms. I did not know about the 1.15" minimum throw until after replacing both the slave and master. I could have saved close to $1000 except for the cracked flywheel might not have been discovered. I really could have gotten by with the $2.19 bolt.
Hope this all helps. I know it would have been less stress for me if I had the chance to read this first. Good Luck!!!
[This message has been edited by bvander (edited 09-11-2011).]
