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Old September 5th 08, 09:05 PM posted to alt.autos.bmw
Jeff Strickland
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Posts: 1,481
Default E39 Vibration on Braking - help please !


> wrote in message
...
>I had a similar problem and still haven't quite fully resolved it. I
> have an E39 with 75K. At around 60K I had both my front rotors
> replaced by the dealer in Miami. This was around December 2007. Since
> then I have gone through 2 other front left rotors trying to resolve
> the vibration problems.
>
> First time around I had visible warpage on the left rotor. That rotor
> was replaced by the dealer at now charge. About three weeks later the
> vibration returned. Took it to the dealer again and they said I had a
> bent hub on the left wheel. So I had that replaced (luckily I have
> CPO) though I had to buy the replacement rotor because the warpage was
> caused by the hub, so I was told. Dealer said both pads and right
> rotor were within spec.
>
> Two weeks later I am back at South BMW in Miami with vibration issues
> again. This time I am told that my thrust bushing "might" be the
> cause. The pads and rotors are inspected and they are within BMW
> specs. As for the thrust bushing, they want the tiny sum of $475.00 --
> So I found a small independent BMW mechanic that did the job for $200
> -- But the vibrations are still there.
>
> As I was ready to throw in the towel, I found an article on StopTech
> about the bed-in process. Well I tried this and wouldn't you know, it
> actually reduced the vibrations considerably. So I did it again -- and
> the vibration has only occasionally appeared. So that is why I say I
> still haven't quite resolved it. I may very well have had a bad hub
> that caused the first rotor to warp, but the proper bedding in process
> has probably made more difference then the thrust bushing (which
> weren't visibly bad).
>
> Regards,
> Rick



I drive an E36 convertible. My brakes -- all of them -- were worn below the
min thickness stamped on them and the pads were down to about 3 or 4 mm
remaining. Stopping was smooth and sure, even though the parts were
obviously worn out.

I bought all new rotors and pads from an eBay Store, and the front rotors
were not machined well and caused a serious vibration out of the box. I
called to complain, and another set of rotors arrived on my doorstep within
a few days.

I took those brand new rotors to a machine shop and found they were machined
wrong. I paid $30 to have both rotors machined true on both sides, and they
work very well now. I brought the original set of rotors to the same machine
shop and found the same machine work was needed for them. Another $30, and I
have a set of rotors to use when the need arises.

My point is, it is possible to remove a few thousandths of rotor material to
make them true, and this distinctly a possibility that should be considered.
Take your new rotors and simply have them measured and turned if needed to
make them true.

Good luck.








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