Clutch pedal vibration with engine running.

[Regcabguy]

For the last few months when engaging/disengaging the clutch I get a vibration through the clutch pedal with engine running. Silky smooth clutch cycling with engine stopped. This is in neutral or in gear and driving down the road.
Clutch is an SBC OKHD with only 30K on it. Hopefully, not the throwout bearing. Aside from this issue clutch performs well.
Any ideas?
Thanks.

 

[Motorhead]

Dave, With the engine running, just barely push the clutch pedal, just beyond the free play. Do you feel the chatter then? It can be the throw-out bearing race going bad or worse yet, the pressure plate diaphragm fingers are not even any more. How's the clutch engagement when running? My OKHD goes in this next Wednesday but with the US made AETNA TO bearing.

 

[Regcabguy]

Chris,the vibration is constant even with the pedal out in neutral. SBC OKHD only has 30-40K on it.
Clutch engagement is fairly smooth and consistent with when it was installed.

 

[Motorhead]

About all you could do besides pulling the trans would be to remove the slave cylinder from the transmission. You will need to make sure the slave piston won't come out. With the truck well secured from movement, start the truck in neutral and at idle, carefully feel the clutch fork and see if it wants to vibrate at engine rpm speed.

 

[GCroyle]

About all you could do besides pulling the trans would be to remove the slave cylinder from the transmission. You will need to make sure the slave piston won't come out. With the truck well secured from movement, start the truck in neutral and at idle, carefully feel the clutch fork and see if it wants to vibrate at engine rpm speed.

These slave cylinders do not have a retaining ring and if you push on clutch pedal with slave cyl removed, it will pop apart.

To do your test, after removing slave cyl, to start engine pull the start switch on the master cyl pushrod away from the firewall all the way, hold it there and then start. Then you can let it go.

 

[Motorhead]

These slave cylinders do not have a retaining ring and if you push on clutch pedal with slave cyl removed, it will pop apart.

I think that that is what I said about watching that the piston doesn't pop out. I will add to secure it some way to avoid it coming out. I DID forget that I defeated my clutch safety switch long ago. It is easy to defeat the safety switch temporarily by inserting a "U" shaped wire from a large paper clip. Stick it into where the wires go into the plug. It will defeat the having to push the clutch to start the engine.

 

[Tuesdak]

I had a pedal vibration from a dowel pin missing allowing the trans to "walk" and make the clutch into a flex plate.