throw out bearing help

[Markst1]

Hello,
I noticed the other day a grinding noise when clutch is depresed in my '74 R75. Shifted fine and was quiet with clutch engaged. I ermoved the throwout bearing. It had no grease on it, but looked to be somewhat lubricated (with transmission oil?). The bearings and races didn't look too bad, so I cleaned and greased them. Back together, and the noise is improved but not gone.
Does the thowout bearing need to be replaced? I cant understand how this clutch mechanism works. It is not like any car clutch that I have worked on. What does the pushrod push on?
Thanks
Theo Marks

[BMWRich58]

What does the pushrod push on?

...diaphram spring....
the end of the rod could be wornout. I fits slightly through a hole in the center of the "round" diaphram spring. The rod will wear and "fit deeper" into the spring thus not allowing complete release of clutch when depressed.
About an inch "in" from the end of the rod you'll see a tapered area/shiney,that's where the rod makes contact with the "center area" of the diaphram for compression.
Changing the spring is like changing the clutch disks, "no biggie"...

[Markst1]

OK, yesterday, took it all apart including the pushrod. I lubricated the end of the pushrod, put it all back together, and it still grinds.
Today I looked carefully at the microfiche on the MAX BMW site and it appears that the pushrod was (and still is) inserted backwards. Can this really be? Maybe this has been the problem all along. I guess I'll try turning the pushrod around and putting it together correctly.
I'll keep you posted. :dunno
Theo Marks

[mouse2maus]

I just finished replacing the pushrod and clutch. I do not think that you can actually install the pushrod backwards. There push rod is wider at the rear poortion, and flat on the end. The front end is pointed. If the point is ground down and there is folded metal ( as was mine) it is time to replace. The felt seal is also towards the rear. and would prevent installing the rod backwards.

And do not insert the trust washer/race and bearings backwards, as I did, effectively welding the two parts to the pushrod, and making a really bad grinding sound.

Mouse

[Markst1]

Thanks for the advice. I think that you are right. It will only go in one way. The tip riding up against the flywheel is a little knarly. I think that I will replace the pushrod with new or good used part (thank-you Repsycle) and hope that this cures it.
Theo Marks