Clutch pedal sticks in down position

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jim ayers

jim ayers

fastback fish guy
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Grovetown, GA
Never dealt with a problem like this before - restored a 318 barracuda where the previous owner had put some type of racing clutch in it. It took incredible foot force to depress the clutch pedal down. I replaced the clutch with an OEM style standard duty clutch. I also put new bushings in the z-bar. Now, when I fully depress the clutch pedal (much easier to do), the thing sticks down at the bottom of the floor (only when pressed to the floor, not when partially depressed). I have a clutch return spring attached to the transmission going to the clutch fork. This condition seems to be caused by a massive spring under the dash which assists in depressing the clutch pedal. It does not seem tp be adjustable. Any advice? Do I just need to find a super heavy duty return spring to place on the clutch fork? I have done GM stuff in the past, this is my first Mopar restoration, and i have never seen anything like this before.

thanks

Jim
 
couple things come to mind,
one you need to reduce the amt of toe play lengthen the rod at the fork.
two if all is installed correctly disk, t/o bearing et al, check the length of the rods and z-bar for correctness.

the over center spring (under dash is not adjustable) in some cases it is removed depending on the clutch.
 
Try removing the override spring attached to the clutch pedal.
 
Just a thought, did you happen to use a diaphragm style pressure plate instead of a lever style? If the radial spring on the plate gets over centered (over disengaged) it can hang up. Remedy would be to add freeplay at the top or limit pedal travel at the floor.
Pic of diaphragm and lever style below incase anyone was not familiar with them.
 

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I have had my clutch pedal stick to the floor when powershifting @ 5000 rpm. Pretty scary! As soon as the rpm came down the pedal popped back up. I had all new clutch and all linkage was either new or re bushed. Adjustment on the Borg and Beck (3 fingered) clutches is critical. I remove the inspection cover and adjust the linkage so the throw out bearing almost touches the fingers. (1/16" gap) That's what worked for me. tmm
 
OldmanRick said:
Just a thought, did you happen to use a diaphragm style pressure plate instead of a lever style? If the radial spring on the plate gets over centered (over disengaged) it can hang up. Remedy would be to add freeplay at the top or limit pedal travel at the floor.
Pic of diaphragm and lever style below incase anyone was not familiar with them.
Click to expand...

Yes, it is a diaphragm style. When I bought the car it had a lever style clutch in it and it took tremendous foot pedal pressure to hold it to the floor. This despite the fact the "override?" spring is positioned where it assists holding the pedal down. I will probably remove the spring first, and go from there.
 
It has been posted that the override spring should be removed when using ta diafram clutch. Try it and see what happens. tmm
 
jim ayers said:
Yes, it is a diaphragm style. When I bought the car it had a lever style clutch in it and it took tremendous foot pedal pressure to hold it to the floor. This despite the fact the "override?" spring is positioned where it assists holding the pedal down. I will probably remove the spring first, and go from there.
Click to expand...

toolmanmike said:
It has been posted that the override spring should be removed when using ta diafram clutch. Try it and see what happens. tmm
Click to expand...

Hi Jim, first off i have to come clean that all the Mopars i've owned were automatics and all my 3/4 spd. experience was with GM products..........i know:violent1:. Mike has a good idea to try and that sounds right to me since that style plate requires less pedal pressure. However if you still have the issue afterwards it's probably a geometry issue where the range of motion is just too much for that plate. Different people have different styles they prefer. Some like to floorboard on shifts and some like the pedal higher. I personally like the pedal high with just a inch or so of freeplay, but many times i had to restrict the downward travel. A few cars i even made adjustable stops mounted to the floor. If you like a low pedal then without changing rod pivot points and fork lengths you'd just have to deal with a little more freeplay at the top. I know im getting too complicated but what i'm trying to say is with a little adjustment experimenting you can find a compromise between over engagement and excessive freeplay at the top. Good luck and keep in touch with you results.

P.S. Before someone takes me too task i guess i should mension that when the clutch is disengaged i like to have around a .080 to .100 air gap between the disk & plate. That would be a minimum of course, a tiny bit more wont hurt. I know many recommend a smaller gap, fine for performance only applications, but i like a little more on primarily street setups so in traffic, city, fairgrounds, etc. engagement doesn't feel so "grabby" OK i'll shut up now:D
 
Yeah, this might help, on a diaphram. I installed an auto in a manual. The over ride spring keeps the pedal on the floor; out of the way. lol.
 
If you have a long style pressure plate and the over spring removed it will stick to the floor.
 
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