spodeboy

iTrader: (1)

I have been trying to figure is out on my own for too long. I put a Tremec behind my 400 and a Centerforce clutch. When I first start driving the car, the clutch works great, it shifts easy. When I start driving it hard, the clutch pedal gets soft and it won't shift at all. It takes a couple of minutes driving easy and then it comes back. I have no idea, but do you think that it could be my Centerforce? It has the clutch locks on the pressure plate that slide out. A little help is appreciated. Thanks

swerve-driver

I'm not sure what you mean by driving it hard.
If you mean shifting alot in rapid succession, you problem could well be that the fluid in the hydraulic clutch can't return in time for the next shift (compression of the clutch pedal). This problem can be caused by having a restriction on the hydraulic line where the hose is crimped to the fitting. The fix is to knock the roll pin out and drill the fitting out slightly then re-assemble I'm retty sure there are posts on this website concerning that procedure.

Or, the clutch may have not been broken in properly and when you start to get on it the clutch may start to slip and glaze and then slip progressively more. Then after it cools down some, it works a little better than when it was hot.

I have a CenterForce Dual Friction clutch in my car (350 vortec w/ T5) and I broke it in for about 200 miles of very easy driving, since I was breaking in a new motor and Baer brakes as well. In terms of pedal pressure, the clutch feels just like the original. In terms of grab, between the 350 and a rear end with powertrax on it, the bite is excellent and have had no problems.

So, I'd need a little more specifc info from you before suggesting what to look at first. Could be one of those two things, could be an unknown third.....
Best-
S-D

spodeboy

iTrader: (1)

I mean just getting in the gas, full throttle acceleration to redline, no power shifting. The clutch doesn't slip, it just won't disengage when I push the pedal down. And the pedal feels funny, not like there is no fluid, but like something is flexing in the system. I replaced the lines with braided stainless steel lines, so there is no flex there. A new slave cylinder was put on as well. What do you think?

swerve-driver

Replacing the slave and lines could mean that there is air in the system- just like when doing brake work.

I have never bled a hydraulic clutch, but other posting on this site indicicate it is very tough to bleed them properly.

I see GM sells the whole unit, pre-bled for about $88.

Could it be trans synchros? When you get the hard-shifting condition, try to "double clutch" it. To see if that helps.

I was thinking that maybe your hyd. line could be too close to exhaust header or something and is heating up during use, but that doesn;t explain how proper function returns in such a short time.

Have you gotten under it and had someone work the clutch to check for anything visable?

Just trying to think of alternative causes..


Anyone else?
S-D

RB83L69

https://www.thirdgen.org/techbb2/sho...hreadid=171402

swerve-driver

And behind door #3...........

Sounds like a plausible explanation, but it doesn't address the sentiment of Spode's first post that says it works OK at first and then gets worse.

Could that (working OK at first and then get worse) happen if the TO bearing is on backwards? I would think it would cause trouble all the time?

I suppose it couldn't hurt to verify that the TO was installed correctly.

Hmmmmmm. I'm about out of ideas, unless you have any more observations/input Spode-man.

Best of luck-
S-D

spodeboy

iTrader: (1)

I did not install the bearing incorrectly. It is a good suggestion though. About the thing heating up, I installed 2 insulation wraps to the line, from Earls Brakes, and also devised a heat shield to keep it cool. Any other suggestions? I am at a loss.

Cronic3rd

Is it bled and is there enough fluid?

swerve-driver

That would bring me back to one of my previous points, also as Chronic mentions in his last post- It might not be bled correctly.
Do a search on bleeding those hydraulic clutches- they are really tough to get right.
I haven;t done it, so have no first hand experience, only what I read in old posts.

Also was wondering- was everything working properly before the swap?
Did you replace the trans, clutch and hyd. lines at the same time?

Did the problem just show up after working correctly for a while or has it been like this since the install?


S-D

spodeboy

iTrader: (1)

Yes, the stuff was working well before the swap. I had a T-5 in there when I replaced the slave and hydraulic lines. I had already bled the system and it worked well. When I did the swap, I didn't remove any caps or seals, I just left the slave cylinder hanging. I know that is not air in the lines. Keep the questions coming.

swerve-driver

Dang dude, that is a tough one. How come you replaced the slave and lines?
I wonder if maybe the master could have a leaking seal or something..... similar to when the o-rings crack/leak on a brake master cylinder.

Does engine RPM have anything to do with your ability to shift?

I'm just trying to think if it is something with the physical workings of the clutch mechanism.

What model centerforce is it? Did you contact Centerforce about the problem?


S-D

FstBrd6point3

i chased around a problem like that in my s-10 for a while, turned out there was just a tiny bit of air in the line.... buy a **** load of DOT3, and find two friends, you get under the car and hook a hose up the the bleed tube and submerge it in some DOT3, have one friend engage and disengage the clutch, and have the other friend make sure the master is completelly full at all times. problem solved for me.... I was positive my clutch was bled right, until I did it again and solved the problem.

rjmcgee

Maybe the clutch master cylinder is getting worn out. When you shift normal, you press the pedal slower than when you try to shift it real fast. The fluid is bypassing the piston?

That sounds kinda far fetched.

rjmcgee

The more I think about what I said the more I think that is wrong. It would be the other way around.

spodeboy

iTrader: (1)

I guess I'll try bleeding it again, but I know that it is not the case. I had no problems before the clutch and tranny change. My bellhousing and the clutch itself are the only players in this game. It almost has to be the clutch, but has anyone had a problem with a Centerforce clutch?

rjmcgee

Bad clutch fork?

spodeboy

iTrader: (1)

Again, it was perfect before the swap. It is not bent. Is there another factor involved? And why would it be dependent on how I drive the car, Even if I granny shift the car, but run it hard it still doesn't want to shift. And now it kind of feels like there is a notch in the clutch. As I push it in, it has a a bump in the middle of the compression. What do you suppose that is?

swerve-driver

Just trying to think of other possibilities- The clutch went on the right way, correct? I know mine had a sticker on it indicating which side went towards the flywheel.


S-D

spodeboy

iTrader: (1)

Yeah, I am pretty sure. Though I don't remember exactly. Maybe I'll look at that when I am changing the cam in the car too. I guess I just have to bite the bullet and take the ******* thing out. This sucks. Oh well, thanks for all of your help everyone.
I'll let you know what I find, hopefully.

330hp_91RS

Dammit to hell, I just spent 5 mins. telling you exactly how to bleed it and the freakin' computer deleted it.

Sorry, I'll do it later.

swerve-driver

91RS:
I take some comfort in knowing that kind of stuff happens to other people besides me!
S-D

BlackBeast'88

I have that same problem as well. When I put my '88 formula up to hi rpms 4-5g's I can't change gears either. I can only shift when I come back down to 3g or lower. I have a CF dual friction clutch as well w/T-5 tranny. I changed my slave cylinder today to no avail. My tranny has also been "upgraded" with new gears and syncros. This one has me beating my head in. Spodeboy if you get some info offline that helps please let me know and I'll do the same as well. Also, guys keep the suggestions coming....

spodeboy

iTrader: (1)

Hey BlackBeast, do you think that it could be those steel riders that are on our pressure plates? I wonder if those things are getting stuck out and will not let us push in the clutch. It simply overpowers our hydraulics for the clutch actuation. What do you all think?

BlackBeast'88

Spodeboy I'm not sure but I hope to find out soon. I'm going to have my car check out by a pro within the next month. I getting sick and tried of not being able to shift at 4-5grand. I mean I can't even pull the shifter out of 1 or 2 gear.....I'll keep you posted

swerve-driver

If the piston was unable to extend, by rights you would not be able to depress the clutch pedal, unless something was leaking or bypassing.
I don't know if there is an overpressure relief on the master or slave, but i think I remember you saying that the clutch was -soft- at high RPM?

Did you contact Centerforce and/or Tremec for their input?

S-D

Hulk0202

I had a problem with my t-5 disengaging and I felt a "bump" in the travel. It ended up being my clutch fork pivot ball. It screws into the bell housing and mine had come loose.

89formula#1

mine was also doing that, at high rpm it would grind and after beatign on the car or drivng for a while it woudl be reallyt hard to get into gears, i went to the junkyard got the master,line,and salve off a v-6 car for 40 bucks put it on and its perfect now. if u do this just make sure u take it all in one peice and don't let any fluid get out. goodluck

Stephen Thomas

I would have to agree with Hulk0202's thinking.. While reading everything I was thinking the fork pivot ball or the fork prongs itself that hold the foke to the piviot ball, espessially if you feel it catching. I had problems for the longest time breaking z bars, which were used only in 82-83 after almost pulling all my hair out I discovered it was the fork and pivot ball. It always had the sensation of something flexing. The fork would come off the pivot ball and screw everything up. With the hydraulic it might be causing to much motion in the fork causing it not to push against the pressure plate when you push the pedal.

swerve-driver

Stepen-
How does that jive with his observation that this only occurs after getting on the car and then returns to normal and works properly?

I am still partial to the idea that there is something wrong with the hydraulics of the clutch, but time will tell.

S-D

Stephen Thomas

I am still partial to the throw out fork. One question for ya .. how hard is your clutch to push. It shouldn't be hard at all especially if its hydraulic, it should be like a hot knife though butter, not hard at all. The problem that swerve-driver was talking about how the fluid might not be getting back to the reservoir quick enough and having to drill out a tube is more of having to do with a forth gen slave cylinder and it has to do with the car grinding into third/forth gear.. To answer Swerve-drive's question on while it would only be doing it on fast shifts, well your engaging and disengaging the pedal about 4 time in 10 sec. and if the prongs are broken off the fork.. it can't hold itself to the pivot ball, the clutches engages faster then the fluid drains back resulting in it not staying on the pivot ball. when you disengage the clutch again the fork will not be on the ball causing the angles not to be right and making the pedal really hard.. well harder then normal. its just an idea another thing to think about.

BlackBeast'88

There's absolutely nothing wrong w/ my clutch. It works great...easy to depress and everything. The problem occurs with me not being about to move my shifter at hi rpm's. It also occurs when engine temps get above 200 + degrees.

laiky

I would guess that the fluid in the master/slave assy is old and has absorbed some water. You may have it too close to the exhaust manifold and when it gets hot the fluid starts to boil slightly and becomes compressible. In that case its the same as air in the line but it only happens hot. If you can afford it get a new one ( all three peices still sealed) if not take it all apart drain the fluid and refill with premium DOT4 and bleed. Don't forget to check the routing of the tube.

spodeboy

iTrader: (1)

I took off my tranny and bell housing to look at the clutch. I found that when the rpms are above 4000, the steel sliders in my Centerforce Dual friction were going past the rev lock position. They are over travelling. I called Centerforce and they said, sorry. Nothing can be done, I now own a $280 piece of trash that the own company won't back. What a terrible company policy. I can't believe that they sell a High performance clutch, that if you put it in a car that is not stock, they don't honor the warrantee. Anyway, who has a good brand for a pressure plate? I am going to run the clutch but replace the pressure plate and I want something that I KNOW WILL WORK. Any suggestions?

Cronic3rd

I can't beleive that centerforce would not replace that clutch. It is a good thing I decided agianst a CF clutch I have no desire to give my money to a company that won't replace a defective product.

swerve-driver

Did Centerforce offer any particular reason why the clutch locks were not operating properly?
It seems kind of weird that those things are giving you grief. I have no trouble shifting in the 4000RPM range.

Let me know if they had anything to say as far as why the clutch locks were the problem or if that is the way they are expected to operate (?).
S-D

spodeboy

iTrader: (1)

No, they didn't give me an answer. The guy was a real jerk. I am going to call back and ask for a supervisor. I will let you know what I find out.

377Z

iTrader: (1)

Spodeboy--what ever ended up happening? Did you ever get anything out of centerforce?

I have the similar symptoms. Well, had--until the hydraulics gave out.

Was coming back to Illinois from Michigan yesterday, and traffic was a biatch and it was near 90 degrees out so the car was good and hot(230+ on the guage). I'm about 30 miles from my house when it starts to REALLY become a problem--clutch feels like a rock and is not disengaging. I'm on a toll road pretty far from my house on a Sunday night so I decided to try to make it home as the tow charge would've been astronomical. So, at about 20 miles away from my house the pedal gives at a toll booth, and voila, no more clutch. Luckily at this point traffic lightened and I was able to get home with only two complete stops (start it in gear, and shift clutchless trucker-style).

Last few days it'd be more difficult to get the car in gear from a stop after prolonged city driving (I'm guessing heat plays a role here--mine is also hydraulic), but never so difficult as to cause serious concern. 4000-5000 RPM shifts were always smooth. I still would've looked at it sooner but my winter car/parts hauler is in the middle of a frontend rebuild, so I put it off. I have yet to inspect it thoroughly as this happened last night (I'm at work) but did find no fluid under the cap when I peeked. I'll put it on stands and inspect it tonight (won't have time to disassemble though, gotta finish the other car); any ideas on why the pedal felt like a rock?

CAT

I also have been struggling with this same issue, I have not corrected the problem yet however maybe able to offer some possible areas to look. Did you change out the bell housing with an aftermarket? Also you may have to shim the flywheel off of the crankshaft. The tolaernces for a hydraulic clutch have to be exact as the factory had set them for or you will have problems!
I have just recently installed a Hayes clutch, PP and TO bearing. The PP is a diaphram type street strip. I also have installed a lakewood bellhousing with the block protector. The block protecter is about a 1/8" thick, in which case I had to shim the flywheel out towards the tranny that 1/8". I installed a richmond 5 speed in mine and its like when it gets hot after the heat has made its way back the driveline, its like the tranny is gear bound and very hard to get in gear. I tried synthetic gear lube an no help yet. I'm still diggin as well. Maybe some of this may help for you or for others. It's really frustrating I have a 500 hp small block and cant power shift it. One additional item that is very critical is that you have dial indicated the hole in the bellhousing with the centerline of the crankshaft. The max. allowable tolerence on those is only about .020 thousandths. If the bellhousing is not lined with the centerline of the crank,, and its pulled, the input shaft will be running on a bind therefore not allowing fro proper shifts. Also check to make sure the input shaft of the tranny is not extenting to far into the pilot bearing and contacting the crank. Sorry for the long wind but just some items Ive run across so far. By the way none of which are my problems, still searching.

377Z

iTrader: (1)

Soon as I jacked up the car I found the problem--the pivot ball backed out. I didn't follow up on this thread because when I got no response I figured that the others had since unsubscribed.

All parts are stock except the Centerforce DF clutch kit. Which, I feel the need to point out (every chance I get) was 3oz. (!!!) out of balance. But I digress. I remember advice about verifying runout on aftermarket bellhousings; I was going to do it on the factory piece but haven't bought the mag base for the indicator yet.

I still don't understand how this (backed out pivot) would make it feel different when the car was cold, but oh well. Luckly the slave cylinder, which I apparently exploded, is only a $53 regularly stocked part at autozone. I also hear it may be a bit stouter than the factory piece (though I don't plan on doing the same thing to find out). Boy am I looking forward to the joys of bleeding this system.

I wish I had 400hp to put down, unfortunately its probably only about 170 at the rear wheels. Sounds like you have a nice setup, good luck.

spodeboy

iTrader: (1)

FINALLY I have the fix. I found that my hydraulic slave was too far away from the clutch fork. It was strange but my clutch seemed to have too much play. I messed with it but never found anything in the linkage. Anyway, the point is I welded a nut to the back of my adjustable pivot ball. This gave me 1/2" more adjustment. It was just what the doctor ordered. I can't believe how simple a fix that it was.

laiky

are you using an after market bellhousing??

spodeboy

iTrader: (1)

Ya, a Lakewood. Not sure, but mine may be different from everyone elses. I do not have an adapter plate to rotate the transmission back to center like everyone else. My tranny is bolted straight to the Bellhousing. There are no other modifications to my bellhousing, shifter, or transmission it just lines up. My tranny is sitting about 2 inches farther forward than the T-5 was at the shifter. I am not sure if it is because of the way the case is made, but my crossmember lines up underneath for the transmission mount.

BlackBeast'88

spodeboy et al

Here's an update on my situation. I had the tranny take out and trans guy said that my casing was wearing out and the trans was basically junk. Remember I had the same problem with not being able to shift at hi rpms and when my temps go above 200. Has anyone else had this problem?

Let me know before I buy another tranny.

mjpell

The McLeod clutches are an excellant clutch. See http://www.mcleodind.com.