Clutch Shimmy Problem

[Joep]

Whenever the ambient temperature is hot (>25C) and I have driven my csi for some time, so engine is certainly at operating temperature, I experience a problem when raising the clutch to accelerate from a stand still position.

There is a shimmy/wobble which seems to be coming from transmission part necessitating the application of more engine power to move the car. The warmer the weather and the car is the worse it gets since it does not appear when engine is cold. Once rolling and at higher speeds I do not experience the wobble when raising the clutch.

Some 5000km ago changed the clutch disc, pressure group, bearing and arm. Before that it used to appear even more with the old clutch set. Did not experience it untill now again.

Maybe some of you gentlemen who enjoy the higher temperatures more frequently than we do here in Holland, have an idea what would cause this symptom. Suggestions?

 

[MMercury]

Whenever the ambient temperature is hot (>25C) and I have driven my csi for some time, so engine is certainly at operating temperature, I experience a problem when raising the clutch to accelerate from a stand still position.

There is a shimmy/wobble which seems to be coming from transmission part necessitating the application of more engine power to move the car. The warmer the weather and the car is the worse it gets since it does not appear when engine is cold. Once rolling and at higher speeds I do not experience the wobble when raising the clutch.

Many things come to mind regarding "wobble" or "judder." Among them: worn or sloppy motor and transmission mount/s, leaky rear main seal, glazed pressure plate, contaminated disk assembly, over-greased trans output shaft splines, worn transmission output splines and even a worn/dry pilot bearing/s (housed in the crankshaft). Then, there is the remote possibility that your clutch pedal linkage is too tight, so that when the hydraulic fluid warms, it causes a slight disengagement of the clutch plate and a slight slipping.

If the sleeve/guide upon which the throwout bearing rides is galled, gouged, rusty, dry or seriously worn, this can also cause strange or unexpected pedal feel/behavior which you may be confusing with clutch engagement/disengagement. This part is often overlooked when a new clutch and throwout bearing is/are installed.

Since your clutch design is fairly generic, aside from consulting the obvious (shop manual http://www.e9-driven.com/Public/Library/BMW-E9-Manual/pages/en/21.html#refertoc or the haynes guide http://www.e9coupe.com/tech/autobooks/chapter5/gallery.htm#autobooks_manual_065 ), consider browsing though this site for ideas: http://media.centerforce.com/DiagGuide/DiagnosticGuide04DL.pdf

I am sure others may have more specific and alternate suggestions. Best of luck.

 

[Stevehose]

Have you bled the line to your slave cylinder - possible moisture?

Does your slave cylinder work smoothly, greased, and in good condition - binding anywhere?

Was your flywheel resurfaced when you had the clutch replaced - a hot disk up against an uneven flywheel?

Whenever the ambient temperature is hot (>25C) and I have driven my csi for some time, so engine is certainly at operating temperature, I experience a problem when raising the clutch to accelerate from a stand still position.

There is a shimmy/wobble which seems to be coming from transmission part necessitating the application of more engine power to move the car. The warmer the weather and the car is the worse it gets since it does not appear when engine is cold. Once rolling and at higher speeds I do not experience the wobble when raising the clutch.

Some 5000km ago changed the clutch disc, pressure group, bearing and arm. Before that it used to appear even more with the old clutch set. Did not experience it untill now again.

Maybe some of you gentlemen who enjoy the higher temperatures more frequently than we do here in Holland, have an idea what would cause this symptom. Suggestions?

 

[Joep]

gents, thanks for the pointers and quick replies. By the wya, the transmission I mounted, is also new, so new splines etc , so were the mounting rubbers. The slave cilinder was also new and works fine and does not bind, and was bled when changing the transmission. Even oput on new drive shaft including new bearing.

What I did notice was that the flywheel surface was uneven. Your suggestion this could be a cause for the symptom, since everything else is in good or excellent shape, seems most likely.

I even remember when noticing the unevenness on the flywheel when doing the overhaul that my assumption that I had thought of everything to replace was shaken a bit. I had hoped to stay away from the transmission for some time. Well, at least I know the routine.
J.

 

[Stevehose]

If you are going to go back in there - also consider replacing the pilot bearing (in the end of the crankshaft - not the throwout bearing) and check the rear main oil seal - if it is in good shape and not leaking then some say leave it alone, mine was recently replaced by the PO so I didn't touch it. These 2 items plus the flywheel resurface should take care of having to go back there for a long time. I've removed my transmission twice recently by myself, I don't want to do it again anytime soon.

gents, thanks for the pointers and quick replies. By the wya, the transmission I mounted, is also new, so new splines etc , so were the mounting rubbers. The slave cilinder was also new and works fine and does not bind, and was bled when changing the transmission. Even oput on new drive shaft including new bearing.

What I did notice was that the flywheel surface was uneven. Your suggestion this could be a cause for the symptom, since everything else is in good or excellent shape, seems most likely.

I even remember when noticing the unevenness on the flywheel when doing the overhaul that my assumption that I had thought of everything to replace was shaken a bit. I had hoped to stay away from the transmission for some time. Well, at least I know the routine.
J.