Originally posted by Archie:Fiero Clutch: Symptoms & Cures Archism #7
I hesitate to call this an Archism 'cus some of the cures may well have been discussed by others long ago. However, I would like to make this letter reflect the collective knowledge of all those who have come before be they here, moved along or in Fiero heaven.
This information will be updated from time to time and reposted, I have made provisions that it be passed along upon my demise. Submissions for inclusion in this list are encouraged. Please send them to Clutches@v8archie.com
The symptoms:
A) The car moving when starting the engine with the trans. in gear and the clutch pushed in.
B) Hard to shift into reverse or 1st. with the engine running.
C) You say: "I just put a new clutch in and it still don't work right."
D) You can get in gear but it grinds.
E) You push the pedal all the way to the floor to engage.
What to look for:
1) Obvious leaks: You can't expect it to work if you have a puddle on the floor!
2) Is it bled properly?: You can put in a new pedal or replace all the parts, but if you bleed it the way the books tell you it'll never work. Proper bleeding procedure? See Archism #4 previously posted.
3) Do you have the steel pedal?: IMHO 95% of the above symptoms are caused by the Aluminum pedal. If you want your new clutch to last a long time, or your old one to last longer, check the clutch pedal. 1984 thru 1986 originally had aluminum pedals and they have an inherent design flaw. If you have the alum. pedal I HIGHLY recommend replacing it with the steel pedal PN 10066423.
4) You have the steel pedal, & still have the symptoms: Check this note: Some factory built '87 & '88 Fieros were miss-assembled and the banjo was put onto the pedal up-side-down. Make sure your banjo is mounted with the loop UP as described in #13 of Archism #6. Also: I have seen one case where the factory installed steel pedal had a similar problem (to the aluminum pedal) and when replaced with a new steel pedal the problem was cured (I feel this would be quite rare, but even GM is not perfect). In addition check for other cures in the hydraulic system below.
5) You've checked the above problems and are still looking for a cure: Your problem could still be a leak!!! Carefully peel back the carpeting and inspect as per my suggestion to the list in Feb. 1997 Where I suspected a master cylinder leak "You see, the fluid leaks around the piston into the boot then runs out of the boot down behind the carpeting in the drivers side foot well. The only way to discover this type of leak, aside from removing the carpet, is to look/feel for fluid under the carpet in the area where the master cylinder enters the passenger compartment." In all cases of a leak and some cases of air in the system an observation can be made. With a helper in the car have him push the pedal in all the way and hold it while you closely observe the clutch arm (in the engine compartment). As the pedal is depressed you will see the arm moving toward the engine, hold the pedal in and closely observe the arm. Does it retain it's position or does it slowly begin to return (move away from the engine) observe for at least a full minute. If it does start to return you've got a LEAK SOMEWHERE or a lot of air in the system.
6) If you are always "topping off" the reservoir on the clutch master cylinder and you've read this far then you missed something.....you've got a leak somewhere.
OBSERVATIONS I HAVE MADE ON THE WAY TO SOMEWHERE ELSE
A) Pontiac owners manual states that the Fiero clutch is self adjusting. In truth it is not adjustable.
B) The bore size of the Master Cylinder and the Slave Cylinder is the same size. Except the Getrag Slave is larger.
C) Through one full stroke of the clutch pedal the piston in the Master Cylinder moves 1.20" Maximum.
D) Because of C) the maximum travel of the piston in the bore of the slave cylinder is 1.20"
E) To properly operate the stock Fiero Clutch you need 1.15" of travel in the hydraulic system to properly engage and dis-engage the clutch.
F) Because of E) any inefficiency in the operation of the total system, (I.E. leaks or bad pedal or banjo on upside down) will cause one or more of the symptoms listed in the start of this posting.
G) The Fiero Master cylinder has a "bleed back hole" inside of it. This feature relieves line pressure when the pedal is all the way out thus preventing the T.O. Brg. From riding against the clutch while engaged.
H) Because of G) changing the length on the slave cylinder shaft (runs between the slave and the clutch arm) will not correct any of our symptoms. It will help if you have a aftermarket clutch with a lower finger height.
I) The act of changing the length on the slave cylinder shaft has only one effect on the operation of the system. That is that it changes the relative position of the beginning and ending points of the piston travel in the slave cylinder bore it will not change it's efficiency.
J) Too long of a shaft will cause the piston to "bottom out" in the back of the slave bore making the pedal not return to it's full up position and thus not allowing the "bleed back hole" to do it's job .
K) Too short of a shaft will cause the piston to run into it's stop (a snap ring) at the end of the bore. If the piston reaches the end of the bore before the pedal is fully depressed the banjo will bend, a bad thing.
L) No amount of praying will make a ruined clutch work any better, although it might get you home.
M) Replacement of the stamped steel clutch arm on the transmission with the cast one is way over rated. While its being replaced will not hurt anything. I have only seen bad ones on about 3% of the cars I have worked on.
N) While some advocate replacement of the master and slave cylinders. I have only replaced one master and three slave cylinders on the over 100 Fieros I have worked on, a failure rate of some 2%.
O) Oh!!! Did I mention that having the banjo mounted upside down screws up the geometry, thus negating the effects of B), C), D) & E).
P) Another problem I've seen, is loose or missing transmission to engine attaching bolts. Believe it or not a couple of loose bolts will cause our discussed symptoms.
Q) Also check the slave cylinder mounting to ensure that the slave cylinder is not moving or flexing on it's mounts.
Well I'm sure that doesn't cover everything, but I'm getting tired of pecking for now.
Archie
its always the ones you dont suspect
