When I installed the CF clutch, I didn't open the hydraulic system. Now it doesn't disengage completely. I bled about 4 reservoirs of fluid through it and it got worse. It worked fine before I put the CF clutch in.

WTF is going on?

Does this clutch take more throw to disengage than the stock unit?
Can the throwout arm be installed on the throwout shaft in more than one orientation?

As near as I can measure, it has 5/8" of travel at the slave cylinder. This works out to nearly 1/2" at the throwout bearing, which according to the Centerforce tech rep should be more than enough to disengage it.

When you removed the slave to change the clutch the spring inside the slave extends to its fullest, it is very likely that when you reinstalled the slave and pushed the rod back inti its proper position you also took in a bit of air. Make sure that you follow any one of the various clutch bleeding procedures. When I had a centerforce installed I actually had to cut down my slave throw by installing a clutch pedal stop.

quote Originally posted by Will: As near as I can measure, it has 5/8" of travel at the slave cylinder. This works out to nearly 1/2" at the throwout bearing, which according to the Centerforce tech rep should be more than enough to disengage it.

5/8" at the slave doesn't work out to any where near 1/2" at the TOB.

I'm gonna assume that you have a getrag, Take out the clutch rod from the slave and make a new one about 1/2" to 3/4" longer.

Archie

Waitaminnitt...

I have another Getrag sitting around and I measured 1 13/16" center-center from throwout shaft to input shaft, and 2 7/16" for the length of the external throwout arm...

Oops. Motion ratio is the square of mechanical advantage (Cliff needs a D-OHH smily)

Anyway... This is the clutch you use in your kits, right? Is having to make a new pushrod normal? I thought it was a straight up replacement?

As a clutch wears the piston in the slave recedes to the back of the slave bore. This allows the bore to rust as brake fluid is very corosive. When you install a new clutch the piston and seal is forced over the rusty surface and it ruins the slave. Buy a new GM slave whenever you install a new clutch. Ed Parks will not do a clutch job without installing a new GM slave.

How much travel should there be at the slave cylinder?

I would like to add that brake fluid itself is not corrosive, but the moisture it attracts is. Any time I open up a Fiero clutch system, I bleed all new fluid through it to minimize moisture buildup.

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"Its a Fiero thing... Heck, even I don't understand!"

Timothy E. Smith
1986 SE V6 Blown head gasket :(
1984 Coupe
1996 Ford Probe GT
1999 Chevrolet Silverado Z71
1975 Chevrolet ElCamino SS

I have had my Centerforce dual friction clutch installed for almost a year with very little travel on the clutch pedal to engage/disengage. It got worst to the point I had to remove the switch that prevents the engine from starting if the clutch isn't engaged, so it has to be started in gear and shifted into the next gear at the perfect speed. The best guess from a trusted shop is that the pressure plate has broken a prong, or something is wrong with the disk itself.

If I heard the opinions of Centerforce before I installed it, I would never have bought it. I've heard much better comments about kevlar, or just the stock disks.

Good Luck,
Greg

What opinions have you heard about the CF clutch?

How much travel should there be at the slave cylinder?

I have the dual friction for 2 years now, works great over stock. never slippes with my warmed up 3.2.. Did you replace the throw out? try gravity bleeding the cluth slave .. everything is stock on the trans, still has original push rod. I would measure travel for you but i lost the fuel pump last night at work How bad it=s the clutch pedal bearing and is the pedal badly bent.. I put a new pedal bearing in mine and i can get a <chirp> in third..YEEHA

85GT3.2

I had to make a new rod for my slave after putting my CF DF clutch in. this was with a V8 Archie kit. Works great now for almost 10,000 miles, of course it does slip in higher gears at WOT sometimes but thats a different thread.

Jim
87 GT T-TOP V8
87 GT

quote Originally posted by Archie: Take out the clutch rod from the slave and make a new one about 1/2" to 3/4" longer. Archie

That's exactly what I was going to recommend. The slave piston may be so far into cylinder at rest such that it has very little room to move before reaching the end of the cylinder. Lengthening the rod will have the effect of pushing the starting point of the piston further back into the cylinder.

Farknocker

*you are going to need at least 1" of movement at the clutch slave to disengauge!*

Amazed no one has caught this yet, but 5/8" is just not enough. Likely there's air in the system (did you compress the slave *completely* when bleeding it? you have to; look on archie's page for bleeding tips if you haven't already.)

Longer pushrod may help. May be time to rebuild it (or at least take apart and inspect and replace seals... ok, rebuild

Best!
Ben.

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Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

quote Originally posted by artherd: *you are going to need at least 1" of movement at the clutch slave to disengauge!*

Thank you. Finally.

Here's my take on things: the clutch and TOB are the only things that changed. If they have the same form factor as the stock units, then nothing in the geometry has changed. Why the need for a longer pushrod? That would be a bandaid, not a fix.

I have alittle over an Inch travel on mine. Worked several hours bleeding. I replaced MC and Slave. Longer pushrod wont make a diff. unless the old one wore out the select arm thingy(not good at technical jargon) I Tried putting a longer one one. Didnt do a thing. after finally bleeding it, I put the shorter arm back. No difference. rodney dickman posted on one of my threads that it wouldnt make a difference. I bled archies way. What a PITA. pushing the slave rod in is where I had problems. Only because its hard NOT to make a mess. after doing his way, I drove the front onto ramps and gravity bled. works great now. sorry about the long post.

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JOEJOE Aol:SSFiero
Two 88FORMULAS Red & Yellow and a Black 86GT
SSFiero@Aol.com

quote Originally posted by Will: [B] Thank you. Finally. Here's my take on things: the clutch and TOB are the only things that changed. If they have the same form factor as the stock units, then nothing in the geometry has changed. /B]

Well, the clutch disc itself has changed (replaced a worn one with a thicker new one )

It is rather a band-aid for a messed up slave; (unless you're actually running to the travel limit of the slave cylinder, which is not unheard of actually. Hey, what is your slave arm made out of? Some had a history of bending.)

Realize you did just change the clutch only, but doing that *can* manifest other problems in the clutch (just by moving the range of movement of the slave that little bit diffference from a new versus worn disc!)

Best!
Ben

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Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

quote Originally posted by artherd: Well, the clutch disc itself has changed (replaced a worn one with a thicker new one ) It is rather a band-aid for a messed up slave; (unless you're actually running to the travel limit of the slave cylinder, which is not unheard of actually. Hey, what is your slave arm made out of? Some had a history of bending.) Realize you did just change the clutch only, but doing that *can* manifest other problems in the clutch (just by moving the range of movement of the slave that little bit diffference from a new versus worn disc!) Best! Ben

External T/O arm is cast. Had to grind on the pushrod pocket a little to get it to go in past the coolant manifold on the N*.

Don't forget that the geometry should be fine for all thicknesses of disk from brand new to wore the F@#$ out. If changing from an old disk to a new disk causes problems with the range of motion of the slave, then it's time for a new slave, not a new pushrod.

Has anyone tried jacking the left rear corner way the heck up to encourage bubbles in the slave cylinder to float to the bleed screw?

Just a note...

I have a Centerforce DF clutch in my otherwise stock-drivetrain Formula. I was planning on a beafier engine but the funding fell short when marrage became an issue. ;]

The hydrolics were not opened but shortly after the clutch was installed the system started leaking air. Two new slaves and two new masters later it wasn't any better even with a 'profesional' bleed job that lasted... 3 days. Finally got fed up with the aftermarket parts and blew money on a GM master and slave.

After bench bleeding them I needed no further bleeding for the car to be drivable. It's been running that way for a couple of years now with no other hydrolic issues.

The clutch, however, chatters like crasy now. I suspect it warped due to the shifting difficulties experienced when the leakage was occuring. :]

Trot, the GM buying, fox... ;]

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. /\_/\ _TrotFox Greyfoot_
( o o ) AKA Landon Solomon
>\_/< trotfox@lycanthrope.org

quote Originally posted by artherd: *you are going to need at least 1" of movement at the clutch slave to disengauge!*

waitanotherminnitt...

11/16" master cylinder, 15/16" slave.
I measured 1 1/16" travel at the master, which should work out to roughly 5/8" at the slave. How do you get 1" at the slave?

quote Originally posted by Will: Has anyone tried jacking the left rear corner way the heck up to encourage bubbles in the slave cylinder to float to the bleed screw?

Yes. That's the best way I found to bleed my '85 2.5. Still, my problem was that the pushrod on my new master cylinder was too short! Since you didn't change the master cylinder, that shouldn't be your problem. However, if you want to try it, Rodney makes an adjustable master cylinder pushrod. Couldn't hurt.

When I was trying to diagnose that problem, someone else posted that the slave cylinder should travel 1" - 1.5". With the short master cylinder pushrod, I was seeing about 3/4" movement.

Good luck!

[This message has been edited by MrPBody (edited 05-17-2002).]

hrm, not sure exactly how much master cyl travel I have, but I thought it was on the order of 2.5". Something ain't right here. I know for sure I measured 1.something inches of slave movement with a set of calipers, but that was a while ago. Will check this weekend.

Best!
Ben

quote Originally posted by Will: waitanotherminnitt... 11/16" master cylinder, 15/16" slave. I measured 1 1/16" travel at the master, which should work out to roughly 5/8" at the slave. How do you get 1" at the slave?

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Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

Tried a couple of different things, including Archie method, jack up left side, etc.

It was almost driveable, but after a few minutes it got worse. Now the car drifts like an automatic when the clutch is depressed.

I guess I'll take the boot off the slave and see if there's fluid in it.

sounds like time for a new slave

Best!
Ben

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Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

That's what I was thinking

Should I replace it with a Getrag slave or an Isuzu slave?

I will probably be trying an Isuzu while my Getrag is being overhauled, so an Isuzu slave now makes sense from that standpoint.

It should also give me a shorter pedal throw, although with higher effort.

Has anyone ever used an Isuzu slave on a Getrag?

[This message has been edited by Will (edited 05-18-2002).]

I pulled the boot off my slave cylinder. It had lots of fluid in it.

CarQuest P/N EW155070 is the stock 15/16" diameter Getrag slave.

CarQuest P/N EW104441 is the stock 13/16" Isuzu slave. From the picture its mounting ears appear to be rotated ~90 degrees from those of a Getrag slave.

CarQuest P/N EW104443, which was written next to the picture of the Getrag slave, along with P/N EW155070, appears to be a 13/16" slave with the same external form factor as the stock 15/16" Getrag slave. I don't know what this cylinder fits, as I don't have an application list. I also don't know if it has the same flare threads at the connection.

Hi Will, not sure what to do re; the slaves. I guess try an isuzu in the getrag (watch out for *overtraveling* the CF!) I do have a recomendation, get a genuine GM slave. Anything else is going to die on you in a few months (been my expierence.)

I'd rather rebuild a GM slave, than put an aftermarket slave in, they're all junk.

Best!
Ben.

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Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

quote Originally posted by artherd: I do have a recomendation, get a genuine GM slave. Anything else is going to die on you in a few months (been my expierence.) I'd rather rebuild a GM slave, than put an aftermarket slave in, they're all junk.

Where does one get a genuine GM slave? The dealership with whom I spoke said they'd been discontinued since Jan '95!

I got a new slave from Autozone.
I've installed it an bled 12-15 reservoirs through it, using Archie's method, the shop manual method, and even just having a helper push the pedal while I open, drain and close the bleedscrew; yet still the clutch doesn't disengage. It's worse now than it was. Could the master cylinder be drawing in air on its return stroke? I've got a new master on order. Was that premature?

There's no fluid in the insulation around where the banjo goes through the firewall. It isn't leaking. WTF?

I miss my !@#$%^& power bleeder!!