Vibration when braking... running out of parts to change.
 

When I bought my 05 530i it had bad rotors and a vibration upon braking.
The vibration is felt in the steering wheel, can't feel much in the brake pedal.
If I brake hard, the vibration is way less. Car has 200 000k miles.
No vibrations when I am not braking at any speed.

Parts changed:
- Rotors and pads all around (yes I lubed the sliders and the calipers aren't seized)
- Hub surface, rotor and wheel surface all cleaned.
- Thrust arms and control arms (bushings brand new)
- Front and rear shocks
- Wheel alignment is perfect
- New tires
- Bedding procedure on the pads performed several times.

No play in the steering linkages
No play or noise in the wheel bearing
No play in the rear suspension

I checked the front rotors with a dial and the runout is 0.0015". Measured runout on the wheel bearing surface: 0 on the right side and 0.0015" on the left side.

Front right wheel bearing was replaced by previous owner but not the left side.
I am really at a loss what it could be...

Rotors. Check for uneven pad transfer on the rotors. Caused by over heating the brakes and keeping your foot on the pedal. It leaves uneven pad transfer and that is more than likely what you are feeling. Unless you just put the rotors on and the issue persisted, I would be willing to bet it is the rotors. Ask me how I know. I have gone through two sets of rotors. My last set started doing this and were only 9 months old.

But wouldn't the bedding procedure takes car of it? And wouldn't I have seen the uneven pad transfer with the dial gauge, showing a high spot?

I will change the front left wheel bearing (after 200k miles, should be good thing to do anyhow) and then I will through a cheap set of rotors and see how the car behaves.

theoretically yes, but you could still have bum rotors

I wouldn't do that. Maybe that's the problem. Get a quality set of brake pads and a quality set of slotted rotors.

I use Brembo blank on my race car and never had a warped rotor (They do have surface cracks but never affected the braking).

The rotors I have are Zimmerman, a pretty good quality rotor. I tried different pads and nothing changed. I will scuff my brand new pads and put another set of zimmerman or Textar rotors and see how it goes.
Slotted rotors are ok, drilled rotors are a big no no in my books.

To be continued...

FWIW, back in the early 2000s when I worked for a German car shop we started using Zimmerman rotors on most cars that came in. We had a rash of E39s come back with 'vibration under braking' problems. We eventually started using ATE rotors on those cars and all of the problems went away. I have no idea what it was about the Zimmermans on E39s specifically, because as you state they are a quality rotor. All I know is once we stopped using Zimmermans and went to ATEs the problems stopped immediately. My salesperson at WorldPac was good to me and took all of those Zimmermans back under warranty.

agree 100%. pics of E24?

Worldpac has a very limited choice of rotors for the E60 unfortunately. I will get a set of Textar and see if it is better.

Picture of the 635csi
http://www.bmwe34.net/Ebay/Calabogie14.jpg

Why are drilled rotors a big no no. I have used drilled and slotted rotors for over 10 years with all my cars and never had an issue. Please clue me in.

Mostly, I think, that it has to with drilled and/or slotted rotors being a waste of money for no performance gain in normal use, i.e. non track or racing conditions. The might look cool for the uninitiated, though. There is a down side, however, less braking surface and the risk of cracking, which could be hazardous. Each is own.:(

Bob P.

OMG. you might have the coolest car on this forum. That thing is beyond gorgeous.