What would a vibration in the clutch pedal?

[topaz540i]

As the title states - what would cause a vibration in the clutch pedal? The vibration is rpm dependant and felt while driving, not shifting. The vibration increases with rpm not mph. If im cruising and i rest my foot very lightly on the clutch pad i can feel a vibration coming the the pedal that increases with rpm. The vibration is in the clutch pedal only, not the floor or other pedal. Im not sure of its related but i hate the way my clutch releases when the car is warm. For example, if im coasting up to a red light and push the pedal down to coast or hit nuetral it feels kinda lumpy as the engine and trans separate.<br>
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I assume im on the original flywheel, clutch and pressure plate. Might be time for new stuff even though the clutch is still good. Maybe the clutch was replaced at some point but not the flywheel? Maybe the pressure plate or flywheel is warped or out of balance?

[MartinV]

Sounds like a worn throwout bearing or clutch material stuck on the flywheel. I had the same problem.

[mifesto]

some people dont drop to neutral but will just clutch in at a red light. my good friend wore through a throwout bearing in 20k miles. you guilty of that?

[rf900rkw]

Clutch return spring removed?

[topaz540i]

I usually downshift instead of coast but sometimes rolling up to a redlighht there is no point in being in gear so i Just hit nuetral and coast.
I usually dont like to sit with the clutch pushed in while waiting. For some reason your not supposed to do that.

i do use a clutch stop set pretty tight though. I have heard that could wear the slave rod uneven due to only using part of the travel but i dont see how that would affect me so long as i never remove the clutch stop.

[pleiades]

My guess would be you are feeling feedback from a worn throw-out bearing, with the vibrations traveling down the release fork and back through the slave-cylinder push rod. No noises yet?

[Bandem]

It may be time to drop the transmission and overhaul if you haven't done so. If you plan on keeping your 540i for a while, you're probably going to have do it eventually, so why not do it now and enjoy the car.

[mifesto]

you shouldnt be clutched in at redlight cuz you are simply wearing out the throwout bearing unnecessarily. its also dangerous practice. if you are clutched in at redlight and someone rear ends you, theres high chance you will release the clutch during the impact and shoot your car forward (and possibly into traffic)

[TriniSpeC]

I have this same exact problem and a knocking noise when I depress the clutch. I am changing my slave cylinder this week, i'll let you know what happens.

[topaz540i]

I redid the entire hydraulic system. Feels the same.

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Clutch return spring removed?

Never got around to it. I do have a new spring for it though so i can try it deleted or refreshed.

When i first get in the car in the morning i can lift the clutch pedal with my toe about an inch until its at the upper stop of the throw. I usually just pump the pedal a few times and although the pressure doesnt increase the pedal will usually now go all the way up on its own. Car drives and shifts fine even if i dont pump it. When i pump it up a few times when its cold its as if it loosens up a little, not the pedal joint but down inside the mechanism somewhere. Almost like the clutch bearing is sliding thru really cold grease and the moving it back and forth loosens the grease so it slides better.

[Tom 01 6SP]

I redid the entire hydraulic system. Feels the same.

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Never got around to it. I do have a new spring for it though so i can try it deleted or refreshed.

When i first get in the car in the morning i can lift the clutch pedal with my toe about an inch until its at the upper stop of the throw. I usually just pump the pedal a few times and although the pressure doesnt increase the pedal will usually now go all the way up on its own. Car drives and shifts fine even if i dont pump it. When i pump it up a few times when its cold its as if it loosens up a little, not the pedal joint but down inside the mechanism somewhere. Almost like the clutch bearing is sliding thru really cold grease and the moving it back and forth loosens the grease so it slides better.

I just tried the clutch spring delete for a few weeks. Ended up putting it back in. Def like it better. It was a bear getting it back in. With the spring out i still only had about a 1/8" travel at the top. Once I put the spring back in the pedal is tight at the top.
You might want to take a look at yours to see what kind of shape its in. Don't see how the pedal can drop if the spring is doing its job. Diagram show two springs but mine only has one.

http://www.realoem.com/bmw/diagrams/t/i/42.png

[rf900rkw]

The vibration could be the throwout bearing, but most often is caused by uneven pressure plate finger height. It really doesn't matter, as any or all requires removal and replacement of the clutch. But, in order to feel that vibration, the T/O has to be contacting the pressure plate. If the return spring is in and functioning correctly, it should not be.