Is the clutch pedal return spring and the over center spring the same thing?

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71DodgeDemon340

71DodgeDemon340

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i just came across this in another thread, i had no idea you had to ditch the over center spring when using a diaphragm clutch. My question is, is the clutch pedal return spring and the over center spring the same thing? My spring that goes around the end of the clutch pedal is still in and i have a diaphragm clutch, but it doesnt seem like the spring helps the clutch pedal down, seems to help pull it back up. Shifts fine but will removing this spring make the pedal not return all the way up? Ive looked through some threads but havent seen what exactly they are refering to by over center spring.
 
No. They are not the same thing. The overcenter spring is the big spring inside the car. It is recommended to remove this when using a diaphragm style clutch. The pedal return spring is under the car attached at the bellhousing and the clutch fork.
 
Ok gotcha thanks for the clarification, if i remove the spring what will i notice a difference in? Pedal should still engage and release in the same position correct? Also ive heard the spring assists in both directions but this doesnt feel like it pulls down much.
 
The big spring in the car only pulls the pedal up the last ?? inch?? or less. This is why it's called "over center." If it always pushed "down" the linkage/ TO bearing would always be under pressure

As you start "from the top" and push the pedal down, it takes practice to "notice" when the spring goes over center, but you can feel it. After that point, to the floor the spring "helps" you push the pedal. Sometime, if you have the linkage unhooked, this action is obvious.

The "clutch return spring" is quite weak, and as above underneath. It's job is to help tension the linkage towards the "disengaged" end of travel, and to help keep the t/o bearing away from the clutch
 
Thank you, it makes sense now, i was thinking of that but having a hard time to actually explain it as that, will removing that spring make any noticable changes? Also is the issue of the pedal sticking only with higher rpm? Or is the spring what will cause the pedal to stick? I have never had the pedal stick on me. Granted i never have power shifted at 6k either but i have quick shifted it from 1st to 2nd at about 5k at wot and havent noticed it sticking or over reving.
 
Modern diaphragm clutches should not stick. This was a problem in the old days. Way back in about 75, I had a 340 I swapped into my 70 RR, and decided to go diaphragm. I used a factory GM clutch out of a HP corvette 10 1/2" Worked great. Removed the OC spring and never looked back.

I am pretty sure you want to remove the spring.

You see diaphragm has no RPM centrifugal assist. B&B does that with rollers inside the cover which wedge against the PP. As RPM goes up, the rollers try to fly out, and wedge harder, pushing the clutch "engaged."

Long (Ford) act the same way except they have bob weights on the ends of the levers. Some performance Long PP have removable bob weights you can adjust
 
But i thought the only benefit from removing the spring was to prevent the pedal from sticking when depressed at higher rpm
 
71DodgeDemon340 said:
But i thought the only benefit from removing the spring was to prevent the pedal from sticking when depressed at higher rpm
Click to expand...

I may have misworded some..........I was referring to "the old days" ----- a car with a factory diaphragm such as Chev would tend to "stick down" because of the design of the clutch. On some you could actually depress the pedal in neutral, rev the engine, and feel the pressure become less
If you swap one into a Mopar the pedal pressure for a diaphragm is normally less than a BB so you don't NEED an over center spring, plus you are RIGHT...........an OC spring WILL tend to "help" a diaphragm stick down.
 
So if i havent had a issue in the last 6 years, is there any urgency in removing it asap? Just worried about removing it and changing something, maybe pedal feel
 
Thank you all for the info! Its not hard to depress at all. I may get around to removing it this summer or fall. Im not bang shifting it anyway,

Is there a issue with diaphragm clutches in higher rpm if the clutch is already engaged?
 
I removed the over center spring, didnt seem like there was much tension on it in the up or down position, i could remove it with a small pry bar with a little finesse. With the pedal depressed it didnt seem like the spring opened up much but i guess since its a over center spring i guess it should be most relaxed while the pedal is centered? Anyway i removed it, pedal feels about the same, a good 1 inch of free travel and then you can feel when the clutch is released. I pushed it to the floor and it returns back up with no problems, not sure the over center spring was even doing anything


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Probably wasn't. It was a bear of a job getting mine off. Had to bang a screwdriver between each coil to stick a washer in each one then pry off with pry bar.
 
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