So after going through 3 clutches in 4 miles after full rebuild of literally everything on the car first one cracked, bought a new one pivot ring was out didn't work had centerforce build a new one and same thing happened again pivot ring was out, finally went through jegs and got a good one (never will I ever buy another centerforce clutch). So finally after getting everything back together (have to pull the motor to pull trans) went for a shakedown run made it about a mile, went to Rev match down shift to second at about 30 just to go through the gears with the trans being fresh. Then came the issues, after the Rev match clutch would not fully disengage managed to get home without using the clutch and just shifting at right rpms I have a 3/4 wilwood master and brand new stock slave cylinder. I have .975 inches of travel with the slave and from what I can see if pulls open on the throw outbearing and looks like the clutch should disengage. When started with the brakes applied the clutch grabs does disengage but still enough grab to kill the motor when pedal if fully depressed. Didn't hear any pops bangs or vibrations when this happened. Trans is out of a 1994 Trans Am using fidanza lightweight conversion flywheel and centerforce DFX cluch. Trans is mated to a Gen 1 SBC and setup is in a Datsun 280z any help would be appreciated thanks a lot in advance!

 

did you TQ the PP bolts to 22 ft lbs?

if to tight clutch won't disengage.

I also run the Wilwood McLeod) MC (13/64) bore and stock slave. I could not get all the air out of the MC in it's "installed" position (angle) so bench bleed it and then bench bleed slave then bleed assembled hydraulics.

My installation is also custom but I can remove my hydraulics intack and bench bleed. Not sure what your set-up is and if you can remove assembled hydraulics like a factory F-body but it sounds like there is still air in the system if PP bolts are not to tight.

 

Yea torque is definitely at 22ft-lbs. Very close to 100% sure I have no air in my system. With the slave cylinder spacer off and someone in the driver seat I can see the slave open and close fine with like I stated earlier .975 in of travel. But what I don't get is that when I first started driving it was perfectly fine clutch fully disengaged and went through all the gears fine. Just after about a mile went to Rev match and after that it wouldn't work properly.

 

with the car jacked up in back, engine running, car in gear, pedal all the way down....do the rear tires move?

they should not and if so your clutch is not disengageing. The most common reason, after replacing the hydraulics, is air is still in them.

There have been cases where the lip of the TO bearing peeled back but you should hear noise if that happened.

try pumping the slave by hand from below while someone watches for any bubbles coming up in the resovoir. short pumps on the slave.

if you feel the hydraulics are fully bleed...may have to pull clutch and inspect. also confirm pilot bearing and nose of input shaft are good. a bad pilot bearing draging on input shaft will cause shift issues.

 

Yes wheels spin. Like I stated everything is new clutch, pilot bearing. Just to me maybe I need and extended pilot bushing??

 

you don't need a extended pilot bearing

if you pull your slave and have someone, with just their finger, touch the clutch pedal and just tap it you should immediately see the slave piston move a very slight amount.

I think you have air in your system. you can also try a mighty vac from up top. don't put more than 5 psi as you don't want to suck out fluid, just air.

does your MC have a adjustble rod?
if so open it up a turn or 2 to see it the greater travel solves the issue.

you sure clutch fork is set on TO bearing right?

bent clutch fork or lose fork hold down bolt can also cause disengegement issues so if you inspected those they should be good.

 

Yea inspected the fork it looked OK to me and does look like it is engaging the To bearing OK. If I take it apart I will definitely be replacing the clutch for though.

 

so do you have a adjustable rod on your MC?

 

Yes I do its a wilwood adjustable.

 

well try adjusting pedal out some to see if it resolves your problem with more stroke from MC

 

Yes I will try and keep you posted.

 

Got around to messing with it a little bit today went ahead and adjusted the MC out quite a few turns and still the same thing still drags enough to kill the motor. Will try adjusting it a bit more tomorrow if I have time but did not seem to change when I adjusted it today.

 

the rod length should be within a few turns of the stock length. you may still have air in the system.

by "rev match" how high were your rpm's when you downshifted??

you don't want aggressive use of a brand new clutch untill after 500 mi break-in or roughly 1200-1500 clutch engagements.

I have never been a fan of the "sliding weight" deal of the centerforce

 

Probably about 3k or so. Centerforce break in period I believe is 200mi.

 

I just dont get how it could have worked fine for the first few minutes of driving then all of a sudden go out if there was air in the system wouldnt it have not disengaged from the beginning?

 

so you are on your 4th centerforce clutch is less than 5 miles?

again I am not a fan of centerforce sliding weight deal but given that many almost imediate failures....and assuming you installed them correctly....might want to ditch the CF and get another brand.

I know it is a HUGE PIA to keep pulling the clutch but something just is not right.

try shortening the rod length...maybe you are over extending PP, just a thought

Maybe your hydraulics just let go since they worked for a moment. look for any sign of leak. The Wilwood MC is a nice piece.

From this side of the internet can only respond to words. clutch swap, in itself, is pretty straight forward.

did you have the flywheel re-surfaced...and if so how much was taken off. "maybe" it is to thin now putting the clutch to far away thus not disengageing. Just thinking out loud

Maybe the TO bearing lip bent but you should hear something (noise)....

if you are sure the hydraulics are not leaking and are bleed....you will have to remove clutch for inspection....I would be very hesitant in putting in another CF......but you are not the only one running one.

 

Flywheel has not been received surfaced it's brand new. Motors coming out today. If I get far enough I'll post some pictures and see what I find. I I will keep you posted. But I really appreciate all your help thanks!

 

ouch...well hopefully the visual will show wtf the problem is

a new FW does not need resurfacing so you should be good with the SPEC one.

look closely at pilot bearing as if it is FU and draging on the input shaft, that can cause issues on disengagement.

on install you don't want to draw in tranny by tightening bolts to get the tranny in the last 1/2". this can/will cause pilot bearing damage and/or warp disc hub. The reason tranny can hang up last 1/2" on install is disc is not "exactly" lined up.

 

Got it taken apart found that the TOB is out of round and some pivot ***** are completly out of place and just rolling around inside I believe I counted 3 of them. F#&@ Centerforce. Ill let the pictures say the rest.

http://i865.photobucket.com/albums/a...psa37d64bc.jpg

http://i865.photobucket.com/albums/a...psf0134b67.jpg

http://i865.photobucket.com/albums/a...psac400056.jpg

http://i865.photobucket.com/albums/a...ps040fe12c.jpg

http://i865.photobucket.com/albums/a...ps8de9faa0.jpg

http://s865.photobucket.com/user/egz...04b8c.mp4.html

 

the "out of round" TO bearing....is normal. weird I know but they are all that way. SPEC now offers the "vette" aka LT4 TO bearing (for around $80 IIRC, ouch) which supposedly is stronger than the normal ones. I have one and use it....although people also have reported tearing back the lip on that type as well. Mine came with my SPEC clutch years ago so I have re-used it on a few clutches since. It also has a offset "wobble" to it when you spin it...don't know why they are that way but they are.

your PP is clearly FU and a manufacturer defect. obviously, as painfull as it is, removing clutch to inspect clearly shows wtf the problem was. I would demand a refund from whoever you bought it from and get another brand of clutch. All clutch companies use the same LT1 PP...but CF adds the "sliding weight" thing so they obviously disassemble the PP to do so...and FU putting yours back togeather.

if all you want is a "dual friction" single disc clutch what many have done is buy a $200ish clutch kit from chain auto part store then buy a McLeod DF disc from someplace like Summit for $175 and toss/sell the unused organic disc that came with the clutch kit. Every clutch company uses the same LT1 PP. CF has used the "sliding weight" thing as a system that supposedly increases clamp load as RPM increases. never been on-board with that system. Other companies claim they increase their clamp force by "modifying" their PP's for greater clamp force. SPEC is elusive on the specifics as to how they do it but claim they do. McLeod says they do nothing to the LT1 PP. ClutchNet, I visited their shop to see, disassembles the PP and heats the diaphram and changes the angle of the fingers to create greater clamp force. pedal effort is greater but I don't know if it "translates" to greater clamp force in reality although Clutchnet says it does. I suspect if it does and other clutch companies claim "greater clamp force than stock", I suspect they do the same thing.....but finding any company to publish specifics in "how" is something I have never found.

hopefully your next clutch will be plug & play. I gave up on single disc clutches after killing a variety of brands when I went 383. I now have a McLeod Street Twin. Pricy but man it holds and drives like a stock clutch

why do you pull your motor to remove clutch??