Clutch pedal will not come back

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gunmetal72

gunmetal72

Life is a dark ride
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I just put a new cluth in my 72 340 Duster. The pressue plate is different then the old one. The old pressure plate had 3 fingers and the new one has more then 3 fingers on it (never counted but I think it has about 6 or 7). I adjusted the clutch with about 1 in of free travel and the clutch pedal does not come back when pushed. If I adjust with no free travel, the pedal will come back to the top and work the way it should but the clutch feels kinda spongey of soft. If it has no free travel I am sure the release bearing will be spinning all the time and will burn up in no time. I am thinking I have a peace of crap clutch but thought I would put this out there to see if there was anyone who might have had the same issue. Any thoughts?
 
It has a diaphram clutch plate then, like from Centerforce.

Remove the over center spring.
 
If I take the spring out will the pedal be 1/2 way up all the time and the release bearing running on the pressure plate while driving?
 
No, because you should have a return spring on the clutch fork also.
 
gunmetal72 said:
I just put a new cluth in my 72 340 Duster. The pressue plate is different then the old one. The old pressure plate had 3 fingers and the new one has more then 3 fingers on it (never counted but I think it has about 6 or 7). I adjusted the clutch with about 1 in of free travel and the clutch pedal does not come back when pushed. If I adjust with no free travel, the pedal will come back to the top and work the way it should but the clutch feels kinda spongey of soft. If it has no free travel I am sure the release bearing will be spinning all the time and will burn up in no time. I am thinking I have a peace of crap clutch but thought I would put this out there to see if there was anyone who might have had the same issue. Any thoughts?
Click to expand...

Mopars are picky that way I've found. I have experienced the same problem with mine. It's almost like it needs a little helper spring on the petal to bring it back to the stop, past the over center point. I can just go over a bump in the road and the petal will pop back. It doesn't take much. It might be because Mopars have so much pedal travel compared to other cars I would guess. Have a helper push the clutch down as you watch the action below. Adjust it so that the throw-out bearing to finger gap is around 1/4". You don't want the t/o bearing to ride on the fingers constantly. It will smoke the bearing and tear up the fingers. I took my new clutch to Clutchmasters to have it checked out before I installed it and it is interesting how little fork travel it takes to release the disc. It seems if I adjust it so that it starts to release 2 inches from the top (before the over center) the t/o bearing rides on the fingers. If I adjust the t/o bearing to finger gap the petal releases closer to the floor and the petal wont return over center. All of my linkage has been lubed or replaced and it works very smooth. I wish I would have kept the old pressure plate beause it released perfect. I am guessing it is the finger height that is making the difference. Keep us posted.
 
The over center spring does help pull the pedal up. put it helps depress the pedal once it gors over center. Yes Crackback is right Remove the large spring under the dash. You might want to lube all of your clutch linkage and put a larger return on the fork. this will keep the pedal coming back to the top and give you free play.
 
Gotta thank all you guys for the help. OK, I took the spring out and found the pedal to almost hang there and feel loose. Can't say I like it very much. (Although it did work better) Also the clutch seems to engage close to the floor where before it engaged 1/3 they way back. I think I am gonna change the pressure plate back to the old one. I really don't like the way this one feels. Anyone wanna buy a new clutch??
 
It's not the over center spring....

People always say you need to remove it with a diaphragm pressure plate , then why does it work fine in my car?
My pedal comes all the back up w/ over center spring and centerforce dual friction and has about an 1 1/2 of travel before disengagement.

Make sure the fork adjustment rod is long enough to start, I have always had to lengthen it 1 1/4''

make sure the bushings are good in the z bar and that all is tight.
If the pressure plate is right and all is adjusted properly, the plate should force the pedal back up enough for the over center to take over and pull it up the rest of the way.
 
1wild&crazyguy said:
It's not the over center spring....

People always say you need to remove it with a diaphragm pressure plate , then why does it work fine in my car?
My pedal comes all the back up w/ over center spring and centerforce dual friction and has about an 1 1/2 of travel before disengagement.

Make sure the fork adjustment rod is long enough to start, I have always had to lengthen it 1 1/4''

make sure the bushings are good in the z bar and that all is tight.
If the pressure plate is right and all is adjusted properly, the plate should force the pedal back up enough for the over center to take over and pull it up the rest of the way.
Click to expand...
You probably have a 6 cyl. or late cutch pedal they are totally different then a early or 340 pedal or V-8's. They have a baby spring on them. because they only have a 5 1/4 pin spread. There is also an extra brace to hold the stronger spring on the early 340 pedals.
If your going to make sure of anything make sure you have the correct pedal assembly for the fork your using. Short throw pedals short fork. long throw pedals long fork. I have them out if you need pictures
 
Sounds like you've done your homework old man! LOL
 
Oldmanmopar said:
You probably have a 6 cyl. or late cutch pedal they are totally different then a early or 340 pedal or V-8's. They have a baby spring on them. because they only have a 5 1/4 pin spread. There is also an extra brace to hold the stronger spring on the early 340 pedals.
If your going to make sure of anything make sure you have the correct pedal assembly for the fork your using. Short throw pedals short fork. long throw pedals long fork. I have them out if you need pictures
Click to expand...

I have had 2 pedal sets in my car, one I pulled from a 318 duster, the other came from a '67 3 on the tree slant car cause I wanted a 67' pedal pad set and they were still clean and black painted unlike my 73-74 set.
Both pedals have the exact motion/ratio, and both came back up all the way, so what am I supposed to think?

I do not have a '340 pedal set', if it's really different...why they would bother with different pedals within the same body I dunno..

You're gonna have to explain that one to me, if you don't mind?

The other thing would be this, if so...how is it my as you call it ''baby spring'' able to lift the pedal while this bigger spring can't?

or is that the ratio's fault?

Just thinking about this cause I have never heard anything beside diff pedal assemblies for early 61-66 cars and changed in 67 then 71 & up 'pedal pad styles'
 
1wild&crazyguy said:
I have had 2 pedal sets in my car, one I pulled from a 318 duster, the other came from a '67 3 on the tree car slant car.
Both pedals have the exact motion/ratio, and both came back up all the way...

I do not have a '340 pedal set', if it's really different...why they would bother with different pedals I dunno..

You're gonna have to explain that one to me, if you don't mind?
Click to expand...


Pedals are the same so far as I know. Z bar is different I think slat VS V8.
 
its not a /6 vs V8 thing, its an early vs late thing, sometime around 1970 they changed the leverage ratio to decrease pedal effort due to complaints from people saying it was to hard (yea /6 and V8 use different Z-bar)
 
Oldmanmopar said:
You probably have a 6 cyl. or late cutch pedal they are totally different then a early or 340 pedal or V-8's. They have a baby spring on them. because they only have a 5 1/4 pin spread. There is also an extra brace to hold the stronger spring on the early 340 pedals.
If your going to make sure of anything make sure you have the correct pedal assembly for the fork your using. Short throw pedals short fork. long throw pedals long fork. I have them out if you need pictures
Click to expand...

another thing is this...

The z bar is a body permanent , so a shorter fork would have the rod at a funky angle.

readhttp://www.brewersperformance.com/products.asp?cat=102

And the fork length kinda gravitates around the body style

If you look at the info on this site you'll see no diff fork/pedal combo with 67-72 cars, They sell one fork for all.

fwiw a lot of vans use the same a body fork and pivot.
 
Burntorange70 said:
Pedals are the same so far as I know. Z bar is different I think slat VS V8.
Click to expand...

caferacerx said:
its not a /6 vs V8 thing, its an early vs late thing, sometime around 1970 they changed the leverage ratio to decrease pedal effort due to complaints from people saying it was to hard (yea /6 and V8 use different Z-bar)
Click to expand...

I got that guy's, I bought the v8 z bar along with 600 dolla's worth of parts to convert from brewers, I've done this before lol

I know that the slant is narrower in the bell area so the z bar MUST be longer to reach the bell, but not the pedal ratio.
 
caferacerx said:
its not a /6 vs V8 thing, its an early vs late thing, sometime around 1970 they changed the leverage ratio to decrease pedal effort due to complaints from people saying it was to hard (yea /6 and V8 use different Z-bar)
Click to expand...

See thats the thing...I've run, with the same linkage for both, the 67's and the horizontal lined pedal padded 72'ish and up pedals, with no feel difference.

Thats why, along with never hearing about the ratio change, I'm having trouble with this explanation, I could be wrong...but i need to see it to believe it.
 
Wow, Lots of good info but now I am totally confused, lol. I think to save all the hassel of changing the fork or the pedals or adding length to the adjusting rod, I will just put the other style pressure plate back in it. Would that not be the way to go? I have heard the centre force clutch if better but may not be woth all the extra work it causes. After all, i am not gonna race it, just cruise around and piss off some young kids with a hopped up Honda, lol
 
The pedal assembly on the left is from a 1971 Duster 225 3spd same as 318 .The one on the right 1971 duster 340 4spd. Note the different springs and pin to pin spread. The spring on the 340 is so heavy they added a brace.The later pedals with all 5 1/4 pin to pin and small spring Have a different brake pedal. The bar is turned sidways for impact protection. That is 73 and later. The early cars did have different different assemblies. and if not used with the correct components. will cause disingagment problems . Those of you who think there trans doesn't shift properly this is more than likely the culpret. I have alot of assemblies from different years. They changed alot more than this on early and later 4 spd. cars but this is what your concern is now. Hope this answers anyones questions as every other person has a different opinion. Mopar muscle ran a tech artical on this. They show you how to modify your pin to pin so it will work properly with a 10.5 clutch assembly. If needed I can scan it in and post it. If you have the small spring a diaphram will work without removing it if you keep the smaller spread. But put some ponies in front of it and tires behind it and let me know how it works then.
 
Thanks for the pics, never became an issue for me and I've used 3 diff clutches -hays/southland/centerforce, maybe just luck...

This should be recognized though..
''This modification will work whether you have a three-finger clutch or a diaphragm clutch. The only difference is that with a diaphragm clutch, your pedal may sometimes stay on the floor if you have the over-center spring in place. I wouldn't recommend using a Borg and Beck or Long style clutch without the over-center spring.''MMMagazine quote

My car is in fresno so I can't get under and measure but they did come from a 3/tree / car ....but if thats my case....my pedal still comes up just fine.
 
I,m running the dual friction,centerforce clutch in my 340 4 speed car.I removed the overcenter spring due to the peddle sticking to the floor once in awhile.It was usually at the wrong time.LOL.Peddle works easy and freely now.Good for my bad left knee.:-D
 
Whats kinda funny ...is why wouldn't hey just implement lighter pressure plates for grandma.....then again...how many grandma's went with the stick in the 1st place?

So what year was the change over, '71? or '70?

I'd like to think it was '71, since all performance cars were an epa/gas crunch target, thats when they geared up for the detune of everything including the 340.
 
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