Vibration - Brakes, Control Arm, Wheel Bearing?

[Boxman]

For the past few months I've been experiencing severe vibration while braking at high speeds (~60-75mph).

Story:

Thinking it were my brake rotors being warped, I started the job of swapping out the front rotors with new ones (Brembo Max). During the job, I discovered that my left-front control arm was shot. The dust cover was torn and I could wobble the whole assembly around (I could feel it 'click/wobble'). Putting on the wheel, there is play if I wobble it at 3-9h, but there's no play at 6-12h.

Anyway, so the control arm is shot - needs replacement. This is not my issue however.

I tested the old rotor, and it seemed to vary in thickness by about 0.1~0.2mm across the whole disk. The new rotors show no variation in thickness.

With the new rotors on, I tested again if there was any warpage - I did this by putting on the brake caliper bracket, and resting a stanley-knife on it parallel to the rotor, barely touching it (being careful not to scratch it). Upon rotation of the disk, it would hit the stanley knife and then come loose from it again as I rotated another 180 degrees. So it seems as though this is not completely in alignment. I'd say the difference is about 0.5mm, but this is determined by eye only.

Also with the disks now installed, I can hear the brake pads touching the rotor (on the left front) when I turn to the left, but it doesn't do this when I turn to the right. I've not done a high-speed brake test yet, as I don't want to bed-in my new disks with these misalignments in my front suspension.

So now before I go replace the whole lot (control arm AND wheel bearing), I'd like your expert opinion before spending a lot of money.

My suspicion:

Something went first (either the rotor, control arm or wheel hub), causing the vibration and the defects in all other components.

Recap of symptoms:

- Heavy vibration while braking at high speeds

- Old left front rotor had slight variation in thickness

- Left front control arm is shot - with the wheel on there is wobble/play at 3-9h, but not at 6-12h

- Left front wheel bearing seems not to be in alignment with the brake caliper / caliper bracket.

- New rotors show the same misalignment as the wheel hub.

- When turning left, the left brake pads somehow hit the rotors (audibly). When turning right, no problem.

So now my questions:

- Is all this (vibration, misalignment, pads hitting the rotor while turning) relatable to the control-arm being shot, or is it a combination of factors?

- What are acceptable values for the misalignment of my wheel bearing hub?

- Could my wheel bearing hub have become misaligned (I assumed they were maintenance-free?) by driving around with the vibrations relatively long?

- If my wheel bearing hub is shot, what are the other telltale signs I should be looking for to confirm this?

- Is there anything else that can cause these problems?

Hope you can help me!

[Boxman]

Bump..

[Fishey]

Fix control arm. A bad control arm can certainly cause a vibration and if left unfixed can damage the steering rack. I have to do Audi steering racks all the time as a result of this. Also, does vibration get worse when you load the wheel IE turning? If so maybe take a listen to your wheel bearings.