Erratic Clutch pedal

[Sublime70rt]

Centerforce dual friction clutch is hard to push all the time and when sitting in traffic it will let out wherever sometimes right off floor,in middle, or at top. and its hard to get in 1st gear when its running when its off goes right in. It first started when clutch was letting out at top so i tried adjusting got a little better but not much. I had all the same parts in car before I restored it, with the exception of dakota roller pilot bearing and it worked great. I took it all apart everything seems fine I am stumped. The car is 70 Charger 440 18 spline tranny.

 

[PurpleBeeper]

Hmmmm......
1. Letting out "wherever" sounds like a linkage/z-bar problem. Maybe check alignment & see if the ball stud on the frame is secure (& the frame piece itself). While it's apart, maybe check for any weird wear on the pilot bearing & if you've got the knowhow/tools, double check the runout on the bellhousing to make sure it's not way off-center.

2. Hard getting into first gear while running is a sign of not enough "free pedal" (clutch pedal too low), and more specifically, not enough clutch/flywheel/pressure plate gap when the clutch pedal is pushed down....sort of like you only "1/2-way" pushed down the clutch pedal & tried to shift. Again, I'd check for something being wrong in the linkage/z-bar. Maybe check to see if your little white z-bar bushings are all in one piece.

3. On a related note, did you pull out the over-center spring from the clutch pedal?

 

[coloradodave]

Good information above ^^^^. In addition, with the engine off, I would have someone else work the clutch while you watch the operation of all the linkage from under the hood. Maybe you can spot some movement in directions besides the right ones. I use a Centerforce and the pedal pressure is not hard...

 

[moparnation74]

Remove your over center spring........

 

[Daves69]

Get under there and verify the fork tips are on the release bearing correctly.

 

[Sublime70rt]

Over the center spring was remove when I first installed clutch. All of linkage bushings and ball studs are new from brewer. Pilot bearing looks good. Im not sure what you mean about run out. So nobody think its a clutch and pressure plate problem, you think its some sort of linkage problem. What makes me wonder is all of the same parts were together before with the exception of the roller pilot bearing, and it worked great easy pedal pressure and went into gear no problem. Thanks for replies

 

[Daves69]

...........What makes me wonder is all of the same parts were together before with the exception of the roller pilot bearing, and it worked great easy pedal pressure and went into gear no problem.

If everything is the same, new and tight components that worked previously, then you must have an assembly issue somewhere. The pilot should not affect clutch pedal effort and release.
Not saying this is your issue here, but did you happen to do what's in post #5?
If your release bearing spun as you installed the trans, it's possible one side rolls further onto the fork and the other slips off. And BTW, it always seems to be the top side that's off. This can cause high pedal effort as the bearing is pushed on an angle with one fork tip.
Another possible issue might be the fork not on the pivot correctly or possibly bent/broke.

 

[dvw]

I had the fork bracket crack inside the bell housing. It was no longer a 90 degree shape. Kept opening up further as the crack grew. Pull the fork boot off and have a look. It can be swapped without removing the bell housing.
Doug

 

[2059]

Agree. Had the same set u on the 64 before the blown hemi 727 went in. It worked like a charm. My guess, as said, cracked, loose linkage parts. Check your bell crank stud bushing also the bolts on that stud. You might have a "stack up" of loose worn pivot points. I'd check them all from the peddle to the throw out. Might also check your trans input shaft bearing retainer and make sure you haven't snapped the snout. Good luck.

 

[Sublime70rt]

I took my flywheel and clutch assembly to a friend of mine that own’s a transmission shop today, I let look at it, and he told me that the clutch was slipping, and the small cracks on the flywheel were from heat. I told him that I never felt it slip, or smelled burning clutch even under hard acceleration/ holeshots. He said that he has seen this before with centerforce clutches. He recommended a luk clutch, and said he has never had a problem with them. Has anyone had any experience with LuK Clutch Kits?

 

[dvw]

Any flywheel will develop heat cracks over time, not unusual. All clutches slip at some point. Pull it down in high gear and give it full throttle. Does it slip? I can say for the street/track combo in a high 11/low 12 car the Centerforce Dual Friction is hands down the best clutch I have ever used.
Doug

 

[moparedtn]

I'm reviving this thread because of my recent experiences with the Dual Friction clutch, as recommended by some of you fine folks.
As some know, I recently had my transmission repaired while chasing an annoying noise at highway speeds.
During that process, the mechanic I was using (mostly because he was very close by and had a lift, as I can't do this myself
lying under the car anymore) had it all apart on the bench.
The clutch has less than 500 miles on it, keep in mind. All clutch components from factory 11" flywheel to the throwout bearing
were new from Brewer's including all the pivot hardware, clips, etc.

We get the flywheel out of the car and it's scored heavily, as if the clutch has been slipping.
I never felt the thing slip, not once. In fact, it drove very nicely and I had fallen in love with that clutch, despite the pedal not being
up where I'm used to (Centerforce told me that was normal).
I'm used to getting decades out of clutches; I sold my original owner 5.0 some years ago with 250k miles on it, clutch never replaced,
for example. My diesel tractor has almost 20 years on it now, never even had to adjust the clutch.
I get along with clutches is what I'm saying.

Nonetheless, that flywheel was shockingly scored, so off to the machine shop it went. Dude at the machine shop asked how many
thousand miles were on the clutch; when I told him, he said the thing looked like it had been in the car for years!
The clutch disc also exhibited odd wear, having a raised ridge around about the middle of the contact pads on the flywheel side as well.
Mechanic wanted to replace the whole she-bang, it was so odd.
Of course, there's no such thing as an 11" clutch setup with 23 spline around these parts, so we put it back together as is with the
resurfaced flywheel.

I really like the Centerforce DF but now I question the decision to buy it.
The car is all back together now and drives ok, but the clutch pedal not only is nowhere near the top at rest (over-center spring removed
from the pedal per instructions, of course). When in neutral and idling, the clutch pedal actually oscillates a little and rattles, annoyingly.
I'm seriously questioning the throwout bearing on this setup; I don't see much of a gap at all between it and the clutch diaphragm.
Is the factory spring down there actually enough to hold it off the diaphragm or is the weight of the clutch pedal and linkage enough to
overcome it and make the throwout bearing ride the diaphragm a little?
Do I need to install a light spring under the dash to pick the clutch pedal up to its' old top resting position?

Oh, almost forgot - does anyone have a picture of the throwout bearing/clutch installed in the car, taken with the dust shield off under the car, that shows about how far the throwout bearing should be off the clutch diaphragm?

 

[5.7 hemi]

I went hydraulic throw out bearing, what a difference and the clutch set up from American Powertrain will upwards of 750ftlbs. I love that set up.

 

[dvw]

Should be a spring on the clutch fork to keep the fork from touching the throw out bearing. The pedal should be on the upstop when released. I did notice; mine didn't need to go anywhere near the floor for full disengagement. I fabbed a pedal stop . Made the R/T much better when racing.
Doug

 

[moparedtn]

Should be a spring on the clutch fork to keep the fork from touching the throw out bearing. The pedal should be on the upstop when released. I did notice; mine didn't need to go anywhere near the floor for full disengagement. I fabbed a pedal stop . Made the R/T much better when racing.
Doug

Yep, there is. Spring on fork is in place.
Nope, pedal isn't on the stop all the way up, nowhere near - but then, back when we were going through the install of the CF clutch, folks on here with them told me that would be the case due to the removal of the over-center spring under the dash.
Both of these were confirmed with Centerforce tech support BTW.
Yeah, not too crazy about that but apparently if one does not remove the OC spring, the clutch stands a good chance of going to the floor and staying first time you give it a good stab. Nature of the beast, I guess.

EDIT: Had it back over to the shop this afternoon and discovered the mechanic had flubbed putting the retaining u-clip on the joint between pedal rod and the z-bar, hence all the rattling.
Also noticed the factory rubber bumper stop for the clutch pedal under dash is missing, not that it comes into play right now.
I bought some generic light springs to see if I could cobble up a light pedal return spring just to make sure the weight of the pedal and associated linkage isn't affecting throwout/diaphragm situation as well.
Cobble, cobble....

How have folks dealt with all that slop in the clutch pedal rod to z-bar connection? That's where all the rattling and movement are coming from.
There's a lot of pedal travel for nothing in this joint.


Right now, the factory style clutch is starting to be fondly missed, I don't care how hard it is to depress.

 

[Daves69]

That's where all the rattling and movement are coming from.

Are you using dampening washers behind the pedal rod? Are the spring clip retainers on correctly?

 

[oldmanmopar]

I'm reviving this thread because of my recent experiences with the Dual Friction clutch, as recommended by some of you fine folks.

I really like the Centerforce DF but now I question the decision to buy it.

Oh, almost forgot - does anyone have a picture of the throwout bearing/clutch installed in the car, taken with the dust shield off under the car, that shows about how far the throwout bearing should be off the clutch diaphragm?

I just had a bad pressure plate Borg and beck style. After a short ride it wouldn't release properly and had noises in the peddle. I told the guy it was probably the linkage and we would have to take the pedal out.

He took the car and two days later the the clutch would not release. pins pulled off the pressure plate. The flywheel only in for A week had hot spots on one side. Probably where the first finger pin came off. I then installed a Mcleod diapram removed over center spring and added a heavier fork spring works great.

I use South bend duel friction disc's in our Diesel trucks. None of them release properly and are hard to get in gear. They also rattle when depressed. It is the center plate moving around which causes drag on the disc's. This keeps the trans turning until the synchronizer stops the input. Hence hard putting in gear. The flywheels in these truck are always burned up. But the single disc is to hard to push from south bend. The factory set up slips as soon as you turn the power up.

If you don't have slicks on a heavy car with tons of power the dual disc is over kill for the street. We use them on our trucks because of the weight we tow and the power they make being turned up.
Some of these companies will tell you what ever they need to sell a product. If they tell you a 6 inch diameter drive shaft is what you need would you buy it.

I remember reading your post on your trans noise. I was going to chime in until I saw you fixed it. I Had a fella come here with the same noise. He installed a tail shaft and didn't have the snap ring in properly before tightening the bolts. He didn't need bearings he just needed it reassembled correctly.

 

[moparedtn]

Are you using dampening washers behind the pedal rod? Are the spring clip retainers on correctly?
View attachment 601716

Yes, the isolator you pictured is in place between clutch rod and z-bar, but the clip is missing and I've got another coming from Brewer's.
Mechanic flat botched that part of the work. He said "lousy design" or some such.
I'll admit it's a stone biyotch getting that clip on and once you do, it really doesn't do much to help with the pedal rattle.
The elongated hole in the clutch rod allows the pedal to oscillate. I understand that hole has to be that way, given the amount of movement
in the engine/transmission from torque and such, but I wish Mopar would have done something a little better there.

It's quite unnerving seeing all that oscillation in the clutch, makes me think bad things like the throwout bearing is riding the diaphragm fingers on the clutch and I'm seeing it in the pedal.

 

[moparedtn]

I just had a bad pressure plate Borg and beck style. After a short ride it wouldn't release properly and had noises in the peddle. I told the guy it was probably the linkage and we would have to take the pedal out.

He took the car and two days later the the clutch would not release. pins pulled off the pressure plate. The flywheel only in for A week had hot spots on one side. Probably where the first finger pin came off. I then installed a Mcleod diapram removed over center spring and added a heavier fork spring works great.

I use South bend duel friction disc's in our Diesel trucks. None of them release properly and are hard to get in gear. They also rattle when depressed. It is the center plate moving around which causes drag on the disc's. This keeps the trans turning until the synchronizer stops the input. Hence hard putting in gear. The flywheels in these truck are always burned up. But the single disc is to hard to push from south bend. The factory set up slips as soon as you turn the power up.

If you don't have slicks on a heavy car with tons of power the dual disc is over kill for the street. We use them on our trucks because of the weight we tow and the power they make being turned up.
Some of these companies will tell you what ever they need to sell a product. If they tell you a 6 inch diameter drive shaft is what you need would you buy it.

I remember reading your post on your trans noise. I was going to chime in until I saw you fixed it. I Had a fella come here with the same noise. He installed a tail shaft and didn't have the snap ring in properly before tightening the bolts. He didn't need bearings he just needed it reassembled correctly.

Well, the jury is still out on what exactly was the source of the noise, unfortunately.
The car hasn't made it again since and I even did a little impromptu clutch drop leaving the mechanic yesterday with no drama.

I'm inclined to agree with you on the dual friction clutch, though - although it's nice to have the lower pedal pressure, the thing just doesn't seem to be very street daily driver friendly and requires modifications to the stock clutch setup in order to work.
Maybe I could see it in a race situation or even with a hydraulic or cable-operated throwout? I dunno.
Smarter folks than me can figure all that out.

I'm going to try putting a light return spring on the pedal itself to hold it up off everything, if for no other reason to fight the rattles.
I did notice yesterday that when I held it ALL the way up, it started oscillating again, meaning I had moved the clutch rod all the way to
the other end of the elongated hole in it where it hooks onto the z-bar, so I'll have to make accommodation for that as well.
I have a new rubber pedal stop coming as well - mine has gone missing.

 

[oldmanmopar]

Use a good spring on the fork to the bell. It holds all tight. Pulling up on the pedal with a spring just leaves all that play in the slotted holes in the linkage. I just went round and round with the car here. The modifications to the Z bar for the TTI race Headers this guy bought and the diaphram clutch had me pulling my hair out. All is well now and the customer is happy.

This was on a car that came in for a wiped cam. One thing led to another and the whole motor got rebuild. The car was a Rust bucket. I install all motors from the bottom . When going to put the K member back up we saw the frames were rotted. So it took a whole front clip and floors. Then he wanted the engine compartment painted the original color the car came.

It just came back for the clutch and 355 gears. Now he wants rear quarters and trunk floor. Money is no object to him it was His car from the 70's and he just bought it back.