B10 Biturbo shimmy/wobble braking from high speed

[Stirling]

So like the title says, when I'm braking from anything over 90 km/h there is a violent shimmy (or more significant, like a wobble) in the front end on the passenger side. It disappears as the car slows down.

It doesn't happen if I just let the car decelerate naturally, just with more aggressive slowing.

Control arm? Something worse?

[testdriver]

have you checked if the rotor looks okay, no warping etc.?

[admin]

They are brand new rotors, and it was doing it prior to the rotor replacement.

[Scooter]

Did a quick search and found this as a suggestion:

Loose wheel bearings cause the rotors to run out of parallel with the pads in the mounting bracket and cause excessive runout.

I'm no expert, but that sounds plausible.

[admin]

Thanks, I'll run that one past my long-suffering mechanic.

[quattro20v]

If you have eliminated run out on the rotors, I would check the thrust arms, there an an upgraded one you can get that uses the bushing from a 750i.

Its pretty easy to DIY, I did this a few years back and noticed a difference.

http://www.bmwe34.net/E34main/Maintenance/Suspension/Upper_arm.htm