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clutch will not bleed by katie80
Started on: 12-31-2021 02:43 AM
Replies: 22 (214 views)
Last post by: Patrick on 01-05-2022 06:51 PM
katie80
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Report this Post12-31-2021 02:43 AM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post
I'm rewriting this post since it seemed confusing.

I have an 84 4 speed. I can't get the clutch to work properly. it used to work but I believe there was water in the clutch line. I think it started to freeze when it got cold, so I tried to bleed the clutch like brakes. it didn't work.
I gravity bled, vacuum bled, bled using the slave, bled the master, I can only get the clutch to almost work. I got it to work properly once, but the bleeder was not tightened all the way so it stopped working again. I have replaced the slave cylinder already.
I can't figure out the right procedure to fully bleed the system.
I do not believe it is something mechanical since the clutch fully disengages sometimes (after I get lucky with bleeding I guess.)

[This message has been edited by katie80 (edited 01-01-2022).]

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RotrexFiero
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Report this Post12-31-2021 07:08 AM Click Here to See the Profile for RotrexFieroClick Here to visit RotrexFiero's HomePageSend a Private Message to RotrexFieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
I would begin by replacing your slave and master clutch cylinder. More than likely one is bad, but after that you should have no problem.

Most likely that will be your problem.
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Report this Post12-31-2021 08:35 AM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Quote: "I can get the clutch to engage enough to roll in gear but no more".

That sounds like the clutch is slipping instead of not disengaging. Bleeding won't help a slipping clutch.
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Dennis LaGrua
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Report this Post12-31-2021 01:58 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Engagement/disengagement problems with the clutch can have many causes. A worn master or slave cylinder, bent clutch fork, air in system or even a worn clutch. Bleeding method that you tried doesn't always work. Use a vacuum bleeder at the slave.

------------------
" 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"
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Report this Post12-31-2021 03:02 PM Click Here to See the Profile for LarryinkcSend a Private Message to LarryinkcEdit/Delete MessageReply w/QuoteDirect Link to This Post
There is some good clutch info from V8 Archie on this page, click on the Archisms to open the pages.

http://www.v8archie.com/v8Archie/ToC6.htm
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Report this Post12-31-2021 03:05 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by katie80:

...the pedal was just hard to press.


When the clutch hydraulics are in need of being bled (and the clutch won't disengage), usually the the pedal is easier to push... due to air in the system being compressed.

 
quote
Originally posted by fierofool:

Quote: "I can get the clutch to engage enough to roll in gear but no more".

That sounds like the clutch is slipping instead of not disengaging. Bleeding won't help a slipping clutch.



I agree that what the OP has posted is indeed confusing.
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katie80
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Report this Post12-31-2021 05:02 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by RotrexFiero:

I would begin by replacing your slave and master clutch cylinder. More than likely one is bad, but after that you should have no problem.

Most likely that will be your problem.

I do not believe that that would fix it. I got the clutch to work properly one time but I didn't have the bleeder screw tight enough so it stopped workjng.
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Report this Post12-31-2021 05:04 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post

katie80

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quote
Originally posted by fierofool:

Quote: "I can get the clutch to engage enough to roll in gear but no more".

That sounds like the clutch is slipping instead of not disengaging. Bleeding won't help a slipping clutch.


I meant it won't disengage all the way. I can get the clutch to work if I pump it now.
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katie80
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Report this Post12-31-2021 05:05 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post

katie80

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quote
Originally posted by Dennis LaGrua:

Engagement/disengagement problems with the clutch can have many causes. A worn master or slave cylinder, bent clutch fork, air in system or even a worn clutch. Bleeding method that you tried doesn't always work. Use a vacuum bleeder at the slave.



I tried every bleeding method. I bled the slave, I bled at the slave, I vacuum bled, gravity bled. I do not believe the issue is mechanical because I got the clutch to fully work one time but I didn't have the bleeder tightened all the way.
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Report this Post12-31-2021 05:06 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post

katie80

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quote
Originally posted by Patrick:

I agree that what the OP has posted is indeed confusing.


it was hard to press because the fluid was like a slushie in the cold. I meant the clutch wouldn't fully disengage. I can get it pretty close.
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Report this Post01-01-2022 09:52 AM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
The cold fluid was like a slushie? Does it have brake fluid? Not doubting your knowledge, but it sounds like it has oil or transmission fluid in it. Even on the infrequent dips below freezing in my area, I've never experienced a stiffer clutch pedal.

Just a thought. Does your transmission have the stamped steel clutch release arm? Those things were prone to breaking or bending and were later replaced by a cast release arm.
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Report this Post01-01-2022 10:29 AM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
A stiff clutch pedal could be the result of a bent clutch fork.

------------------
" 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 "

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Report this Post01-01-2022 08:19 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fierofool:

The cold fluid was like a slushie? Does it have brake fluid? Not doubting your knowledge, but it sounds like it has oil or transmission fluid in it. Even on the infrequent dips below freezing in my area, I've never experienced a stiffer clutch pedal.

Just a thought. Does your transmission have the stamped steel clutch release arm? Those things were prone to breaking or bending and were later replaced by a cast release arm.


I didn't look at it when it was cold. I believe it had water in the brake fluid (I didn't touch the clutch system since I bought) so when it got below freezing the fluid started to freeze. i have the cast arm. I can get the clutch working sometimes after I've bled it, but it only works for a little bit before it stops fully disengaging.
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Report this Post01-01-2022 08:20 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post

katie80

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quote
Originally posted by Dennis LaGrua:

A stiff clutch pedal could be the result of a bent clutch fork.



the issue isn't the stiff clutch anymore. the clutch is fine mechanically. i can get it working perfectly but only for a little bit.
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Report this Post01-01-2022 09:00 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by katie80:

i can get it working perfectly but only for a little bit.


It's been mentioned numerous times in this thread for you to replace your clutch slave. It's probably a worn out single seal unit that's sucking in air every time you release the clutch pedal. Buy a nice double seal slave from Rodney.
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Report this Post01-01-2022 09:20 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

It's been mentioned numerous times in this thread for you to replace your clutch slave. It's probably a worn out single seal unit that's sucking in air every time you release the clutch pedal. Buy a nice double seal slave from Rodney.


I already replaced the slave cylinder. I forgot to add that to the post when I rewrote it.
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Report this Post01-01-2022 09:33 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by katie80:

I already replaced the slave cylinder. I forgot to add that to the post when I rewrote it.


With a double seal unit? The single seal slaves are crap.
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Report this Post01-02-2022 08:42 AM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by katie80:


I already replaced the slave cylinder. I forgot to add that to the post when I rewrote it.


Assuming the slave isn't sucking air, next, go up underneath the dash and pull the carpet and padding back from the front firewall beneath the master cylinder pushrod so you can see the metal firewall. If there's no fluid there, then look at the fluid line coming up to the slave. If it's near a heat source like an exhaust pipe or coolant hose, it can boil the fluid. I know the Duke exhaust isn't close, but I believe you have a coolant hose in that area. Insulate it with some plastic wire loom cover. That resolved the problem on one of my V6's.

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Report this Post01-02-2022 10:54 AM Click Here to See the Profile for LarryinkcSend a Private Message to LarryinkcEdit/Delete MessageReply w/QuoteDirect Link to This Post
Rodney Dickman's clutch slave cylinder is the only one to use, it uses two seals on the piston to keep air from being sucked back into the system.

V8 Archie has a lot of Fiero experience to share.

Archism #1: Proper Clutch Bleeding "Forget what the manuals tell you".

Clutch bleeding prodeedure
You can do it your way, But this method always works for me.
After checking to be sure there are no leaks in the Clutch Hydraulic system.
Complete ALL of the following steps before test driving the car:
1) Install a helper in the drivers seat to push in and let out the clutch pedal on command.
2) Remove the cover from the Master Cylinder reservoir.
3) Top off fluid in the reservoir.
4) During the course of this procedure DO NOT allow the "helper" to "pump" the pedal. The "helper" is to depress and release the pedal on command only, DO NOT PUMP THE PEDAL. (See theory below)
5) You will be opening and closing the bleed screw on the slave cylinder as instructed below. CAUTION: During this procedure protect your eyes from squirting brake fluid.
6) (Helper) Press clutch pedal in fully and hold.
7) (You) Open the bleed screw to allow fluid to escape.
8) (You) Close bleed screw.
9) (Helper) Release pedal completely
10) (You) Top off fluid in reservoir.
11) Repeat steps #6 thru #10 no less than 5 times before going to #12 below. NO PUMPING!
12) You have now bled the Master Cylinder and the hydraulic line. YOU ARE NOT DONE YET!!!!! We must now bleed the Slave cylinder. (This is what the manual doesn’t tell you)
13) With no further action to be done with the clutch pedal, you can no remove the "helper" from the drivers seat and have him (her/it) help you do the following.
14) After topping off the Master Cylinder, completely remove the bleed screw from the slave cylinder.
15) Have the "helper" stand at the ready with the bleed screw and the appropriate wrench for installing the bleed screw.
16) PROTECT YOUR EYES!
17) With the bleed screw removed. With both hands grab the push rod coming out of the slave cylinder and push it into the slave cylinder as far as it will go AND HOLD it in.
18) Your "helper" will now install and tighten the bleed screw while you hold the plunger in.
19) When bleed screw is tight release the rod and as it comes out guide it into the proper position on the clutch arm.
20) Top off the Reservoir and the job is complete.
Theory:
Why do I insist that you REMOVE the bleed screw when pushing the plunger in on the slave cylinder? This is simple hydraulics. Fluid or air will always go the direction of least resistance. When you are pushing the rod into the slave cylinder you will find that it is impossible to push it in at a slowly and steadily pace. If you push it in too fast with the bleed screw still in and just unscrewed a few turns some of the brake fluid and/or air in the slave cylinder will go back up the hydraulic line that you just bled, thus necessating your starting over.
When bleeding your clutch....The biggest mistake or miss-conception a person can make is to pump the pedal.
The clutch Hyd. system, unlike the brake Hyd. system SHOULD NOT BE PUMPED. The only thing that happens when you "pump" the clutch is that you make any large air bubbles in the hydraulic system into a bunch of small air bubbles. BTW these small air bubbles are harder to bleed out than larger bubbles.
You cannot "pump up" a clutch. If you have to "pump up" the clutch to make a shift then you have a leak and you can bleed the system a dozen times to no avail.
On the clutch, think about it now, if you could "pump-up" the clutch wouldn't the T.O. Bearing tend to invert the clutch diaphragm and travel toward the engine until it met up with something solid like the flywheel. On a braking system, when you "pump-up" the brakes you force the brake pads into the rotor until the line pressure builds up enough that the resistance you feel when pumping the pedal increases. Further, as you press harder and harder on the brake pedal the pads just increase their pressure on the rotors.
GM Thought this through when they designed the system. To avoid "pumping up" the clutch hyd. system, GM put in a small bleed back hole in the master cylinder. (BTW not an original idea, all Hyd. clutches have it) This bleed back hole relieves line pressure every time the pedal is at the top of the stroke. Didn't you notice when you "pumped up" the clutch pedal that it doesn’t firm-up like the brake pedal does?
The only thing you accomplish when "pumping up" the clutch pedal is to take any air bubbles that are in the system and atomize them into smaller air bubbles, thus making the problem worse. Remember when you were at the soda shop, as a kid, and your parents kept giving you hell about playing with you soda and straw? Same theory here! The more you move that soda through the straw the smaller the air bubbles become.
BTW the "hand pumps" work ok but I’ve never needed to buy one yet. With the hand pumps you still need to ensure that the slave cylinder gets completely bled.
v8archie

V8 Archism #4: Fiero Clutch - Symptoms and Cures

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 Archie@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 a few cases 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 has a bit larger bore. Don’t use an Isuzu Slave on a Getrag because the TOB will overtravel.
C) Through one full stroke of the clutch pedal the piston in the Master Cylinder moves 1.20" Maximum (a little less than that on a Getrag).
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.
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. So change the length of that shaft knowing that the only thing it will do is to move the operational stroke of the slave cylinder piston to a different area of the cylinder bore.
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 highly recommend replacement after trying all the other ideas in these Archism’s.
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.
If you have any questions, requests or submissions address them to Archie@v8archie.com
Archie
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Report this Post01-05-2022 05:45 PM Click Here to See the Profile for katie80Send a Private Message to katie80Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

With a double seal unit? The single seal slaves are crap.


a single seal one I believe. it wasn't the issue it was the master.
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katie80

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Member since Feb 2021
 
quote
Originally posted by fierofool:


Assuming the slave isn't sucking air, next, go up underneath the dash and pull the carpet and padding back from the front firewall beneath the master cylinder pushrod so you can see the metal firewall. If there's no fluid there, then look at the fluid line coming up to the slave. If it's near a heat source like an exhaust pipe or coolant hose, it can boil the fluid. I know the Duke exhaust isn't close, but I believe you have a coolant hose in that area. Insulate it with some plastic wire loom cover. That resolved the problem on one of my V6's.


it was the master cylinder. thank you.
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quote
Originally posted by Larryinkc:

Rodney Dickman's clutch slave cylinder is the only one to use, it uses two seals on the piston to keep air from being sucked back into the system.

V8 Archie has a lot of Fiero experience to share.

Archism #1: Proper Clutch Bleeding "Forget what the manuals tell you".

Clutch bleeding prodeedure
You can do it your way, But this method always works for me.
After checking to be sure there are no leaks in the Clutch Hydraulic system.
Complete ALL of the following steps before test driving the car:
1) Install a helper in the drivers seat to push in and let out the clutch pedal on command.
2) Remove the cover from the Master Cylinder reservoir.
3) Top off fluid in the reservoir.
4) During the course of this procedure DO NOT allow the "helper" to "pump" the pedal. The "helper" is to depress and release the pedal on command only, DO NOT PUMP THE PEDAL. (See theory below)
5) You will be opening and closing the bleed screw on the slave cylinder as instructed below. CAUTION: During this procedure protect your eyes from squirting brake fluid.
6) (Helper) Press clutch pedal in fully and hold.
7) (You) Open the bleed screw to allow fluid to escape.
8) (You) Close bleed screw.
9) (Helper) Release pedal completely
10) (You) Top off fluid in reservoir.
11) Repeat steps #6 thru #10 no less than 5 times before going to #12 below. NO PUMPING!
12) You have now bled the Master Cylinder and the hydraulic line. YOU ARE NOT DONE YET!!!!! We must now bleed the Slave cylinder. (This is what the manual doesn’t tell you)
13) With no further action to be done with the clutch pedal, you can no remove the "helper" from the drivers seat and have him (her/it) help you do the following.
14) After topping off the Master Cylinder, completely remove the bleed screw from the slave cylinder.
15) Have the "helper" stand at the ready with the bleed screw and the appropriate wrench for installing the bleed screw.
16) PROTECT YOUR EYES!
17) With the bleed screw removed. With both hands grab the push rod coming out of the slave cylinder and push it into the slave cylinder as far as it will go AND HOLD it in.
18) Your "helper" will now install and tighten the bleed screw while you hold the plunger in.
19) When bleed screw is tight release the rod and as it comes out guide it into the proper position on the clutch arm.
20) Top off the Reservoir and the job is complete.
Theory:
Why do I insist that you REMOVE the bleed screw when pushing the plunger in on the slave cylinder? This is simple hydraulics. Fluid or air will always go the direction of least resistance. When you are pushing the rod into the slave cylinder you will find that it is impossible to push it in at a slowly and steadily pace. If you push it in too fast with the bleed screw still in and just unscrewed a few turns some of the brake fluid and/or air in the slave cylinder will go back up the hydraulic line that you just bled, thus necessating your starting over.
When bleeding your clutch....The biggest mistake or miss-conception a person can make is to pump the pedal.
The clutch Hyd. system, unlike the brake Hyd. system SHOULD NOT BE PUMPED. The only thing that happens when you "pump" the clutch is that you make any large air bubbles in the hydraulic system into a bunch of small air bubbles. BTW these small air bubbles are harder to bleed out than larger bubbles.
You cannot "pump up" a clutch. If you have to "pump up" the clutch to make a shift then you have a leak and you can bleed the system a dozen times to no avail.
On the clutch, think about it now, if you could "pump-up" the clutch wouldn't the T.O. Bearing tend to invert the clutch diaphragm and travel toward the engine until it met up with something solid like the flywheel. On a braking system, when you "pump-up" the brakes you force the brake pads into the rotor until the line pressure builds up enough that the resistance you feel when pumping the pedal increases. Further, as you press harder and harder on the brake pedal the pads just increase their pressure on the rotors.
GM Thought this through when they designed the system. To avoid "pumping up" the clutch hyd. system, GM put in a small bleed back hole in the master cylinder. (BTW not an original idea, all Hyd. clutches have it) This bleed back hole relieves line pressure every time the pedal is at the top of the stroke. Didn't you notice when you "pumped up" the clutch pedal that it doesn’t firm-up like the brake pedal does?
The only thing you accomplish when "pumping up" the clutch pedal is to take any air bubbles that are in the system and atomize them into smaller air bubbles, thus making the problem worse. Remember when you were at the soda shop, as a kid, and your parents kept giving you hell about playing with you soda and straw? Same theory here! The more you move that soda through the straw the smaller the air bubbles become.
BTW the "hand pumps" work ok but I’ve never needed to buy one yet. With the hand pumps you still need to ensure that the slave cylinder gets completely bled.
v8archie

V8 Archism #4: Fiero Clutch - Symptoms and Cures

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 Archie@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 a few cases 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 has a bit larger bore. Don’t use an Isuzu Slave on a Getrag because the TOB will overtravel.
C) Through one full stroke of the clutch pedal the piston in the Master Cylinder moves 1.20" Maximum (a little less than that on a Getrag).
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.
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. So change the length of that shaft knowing that the only thing it will do is to move the operational stroke of the slave cylinder piston to a different area of the cylinder bore.
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 highly recommend replacement after trying all the other ideas in these Archism’s.
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.
If you have any questions, requests or submissions address them to Archie@v8archie.com
Archie


thank you. I sorted it all out. the master was leaking and also full of metal? I had to swap the pushrod because the master I bought had the wrong size hole and when I took the boot off there was a metallic fluid under it. not sure how that happened. thank you again, very thorough reply.
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quote
Originally posted by katie80:

a single seal one (slave) I believe. it wasn't the issue...


Maybe not this time.

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