Clutch Fork

[paul1969cars]

They pointed out i had wrong linkage which was correct so changed that to rule that out. Still make noise. Will remove tranny and see

 

[Dan Brewer]

I think no matter what, you are probably faced with pulling the transmission again and inspecting/measuring everything. A real pain. Did Brewers have any ideas?

After the linkage was corrected, the noise only occurred when there was ZERO play at the end of the clutch fork. When the free play was loosened up, the noise went away. The buzzing/grinding sound heard is the fingers on the pressure plate hitting the springs in the clutch disc from over-extending the pressure plate. It has nothing to do with the pilot bearing.

 

[paul1969cars]

After the linkage was corrected, the noise only occurred when there was ZERO play at the end of the clutch fork. When the free play was loosened up, the noise went away. The buzzing/grinding sound heard is the fingers on the pressure plate hitting the springs in the clutch disc from over-extending the pressure plate. It has nothing to do with the pilot bearing.

Thanks Dan. I will put it up in lift and see if that happens. If you’re correct. How do you stop the over extending

It’s a stock setup. With Borg and beck style
Clutch with over spring under dash

If there is no fix. Do I just find the sweet spot on the linkage where it doesn’t over extend and call it a day?

Thanks as always for your help

 

[AR67GTX]

After the linkage was corrected, the noise only occurred when there was ZERO play at the end of the clutch fork. When the free play was loosened up, the noise went away. The buzzing/grinding sound heard is the fingers on the pressure plate hitting the springs in the clutch disc from over-extending the pressure plate. It has nothing to do with the pilot bearing.

Thanks for the expert analysis.

 

[paul1969cars]

So I verified that the fingers on the pressure plate do hit the springs as Dan was right.

So I have I think only two options

1. add a block so that the clutch pedal doesn't go all the way down
2. I found the sweet spot in the adjustable linkage that makes the car functional and it doesn't make the grinding noise. but but doesn't come up last inch.

Strange that this is the case because I just replace everything with the same setup as before. Dont know why its has this extra travel now

 

[dadsbee]

Other option is stop pushing the pedal further than it needs to disengage, it's not a box truck.

 

[RemCharger]

What about changing the leverage points in the z- bar?

 

[Daves69]

......
Strange that this is the case because I just replace everything with the same setup as before. Dont know why its has this extra travel now

If you've driven the back sides of the PP fingers into the disc springs, it's possible there is some damage. Flatten out the fingers? Possibly. Bent the pivot? You won't know unless you remove which may be your best path.

When you reset make sure you have the adjuster backed down. Adjust into the plate departure. Try to shoot for 0.050"-0.060" max plate departure between the disc and FW or the disc and PP, (not both), with a feeler gauge. See where the peddle position ends up.

If it's not grinding where your "sweet spot" is set and not shuddering, grabbing, or slipping when engaging, you might try it. See what happens after a bit of use.

However, in any case, you don't want the release bearing riding on the fingers with OC spring pressure. Maybe try a heavier spring on the fork to help get the peddle back to OC. No guarantee.

 

[AR67GTX]

Since you have what seems to be a proper B&B clutch with the assist spring under the dash, and the pedal won’t fully return to the rest unless very minimal free play is used, I don’t quite understand how Mopar intended for this to work. At minimal free play both my 66 Hemi and my friends 69 Hemi clutch pedal gets firm so high that it’s a pain to drive. If we increase free play the pedal gets firm lower which helps a bit for comfort in driving but the pedal doesn’t return to the stop. It’s actually not bad in my 66 although I would like to run a bit of free play and the clutch starts to catch a long way off the floor. But on my friend’s 69 with factory PB his clutch is way above the brake pedal and awkward to move your foot on. I’ve worked under his dash and verified it’s all correct under there. Both of our cars have the over center spring still but I have a diaphragm clutch and he has a B&B clutch but you can’t tell the difference between them and both act the same.

There is so much play in the linkage that the fork spring does very little to return the pedal. There is probably a 1/4” of play in the rod to pin fit on the z-bar connections by design, so it’s never going to pop the pedal up on its own unless you run close to zero free play. It’s more of an anti-rattle spring for the lower linkage. I took some of that rod play out by making a split bushing to fit over the pin on the lower rod and it helped a little. The only thing I can see that would return the pedal positively to its stop would be a return spring from the upper arm on the Z- bar to the firewall like my old Corvette has, but there’s insufficient room between the two on a Mopar to do this and the spring would have to be strong enough to counter the over center spring and then it would defeat its purpose.

I’m about ready to find some way to use a thicker bumper cushion or revised stop under the dash to just lower the pedal resting position a little which will allow a more comfortable driving position any way as long as enough swing room is left for some free play and full disc disengagement when depressed.