engine and drivetrain clutch pedal vibration when pedal depressed

[curt74golf]

Drove my '74 to work today (clear roads, no snow due until the weekend) and on the way home noticed pedal vibration with the clutch pedal fully depressed when shifting. I have a 5-speed, the conversion from ~2008 has <20k on it, and it's noticeable only on the lower half of pedal travel. Not feeling it on the gearshift, nor is there new vibration elsewhere.  Have I run out the clock on the throwout bearing?

 

Curt

Utah

[flagoworld]

Do you hear a whirring sound when the clutch is depressed?

[69NEWCLASSNH]

throwout bearing...

[curt74golf]

Thanks for the replies - no whirring, but went for a short drive Saturday and the vibration is only present above 3000 rpm and really present above 3500. 

Edited February 1, 2016 by curt74golf

[TobyB]

Your clutch pressure plate may be coming apart.

 

Unfortunately, the diagnostic procedure for that is remove transmission, inspect straps on pressure plate.

 

But the other very likely suspect is the throwout bearing, and diagnosing that starts the same way...

 

t

[Simeon]

Sure it isn't the centre support bearing? Sounds like you need to take it apart / get underneath anyway so don't forget to check the easy things first on your way to pulling the gearbox.

[curt74golf]

Center support bearing looks OK, as does the rest of the rubber.  If there's a clutch replacement HowTo I can't find it (the 5-speed conversion articles don't go into much clutch detail), and the Haynes manual writeup isn't great. Pointing me to one is appreciated. If I'm going to pull the entire transmission I may as well do the entire clutch assy.

 

Curt

[Simeon]

Try http://www.bmw2002faq.com/articles.html/_/technical-articles/engine-and-drivetrain/transmission-install-with-motor-in-the-car-r18

The Haynes manual has a whole section on the clutch.