New front brakes vibrate. Bent hub?

[KyDave]

This is a 2004 S80 I5 turbo that my son drives on which I replaced the front rotors and pads with Meyle parts about 6 months ago and everything worked fine. I did a test drive 2 weeks ago and there's a horrible braking vibration in the right front above 10 MPH. There's no obvious hard spot in turning the jacked up wheel. I took the wheel off and found the inside wheel flange bent inward 1/4" out of round over a 4" length which had scraped it's own clearance on the strut mount area. The rotor and pad are barely worn. My son says "I've never hit anything except routine potholes"

I traded wheels to install a known good one, rotated all the wheels, rebuilt the rear brakes and still have the issue. The car steers straight and seems well enough aligned. Is it likely that the wheel flange or bearing assembly could be bent from hitting a pothole?

[MoVolvos]

This is a 2004 S80 I5 turbo that my son drives on which I replaced the front rotors and pads with Meyle parts about 6 months ago and everything worked fine. I did a test drive 2 weeks ago and there's a horrible braking vibration in the right front above 10 MPH. There's no obvious hard spot in turning the jacked up wheel. I took the wheel off and found the inside wheel flange bent inward 1/4" out of round over a 4" length which had scraped it's own clearance on the strut mount area. The rotor and pad are barely worn. My son says "I've never hit anything except routine potholes"

I traded wheels to install a known good one, rotated all the wheels, rebuilt the rear brakes and still have the issue. The car steers straight and seems well enough aligned. Is it likely that the wheel flange or bearing assembly could be bent from hitting a pothole?

I've been upgrading the front suspension and mounts on our 03 S80 T6 and my son and I gave our 08 C30 T5 a four wheel alignment. When you say bent hub or wheel flange do you mean steering knuckle?

Go to a FCP and link the part in question. Was the car vibrating at all before you did any work?

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[KyDave]

Go to a FCP and link the part in question. Was the car vibrating at all before you did any work?

I did the work and it felt smooth. 6 months and a bent wheel later it feels like a warped rotor.

Look up front hub/bearing assembly. I’m wondering if the flange the wheel bolts to is bent slightly such that the rotor wobbles.

[MoVolvos]

I did the work and it felt smooth. 6 months and a bent wheel later it feels like a warped rotor.

Look up front hub/bearing assembly. I’m wondering if the flange the wheel bolts to is bent slightly such that the rotor wobbles.

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Remove all the parts and spin the axle / hub as in the video @ 0:40. Carefully set stationary or hold pointer of some kind near the outer edge careful not to hit the stud and see if it is round.

It's best to have a tool to check for Run Out except without the rotor @ 3:00 in the video.




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[kallekula]

did u clean of all rust from the hub so that the surface the rotor sits against is straight?

[SuperHerman]

Just some thoughtful ramblings. Vibrations caused by out of balance or warped parts generally are more severe at higher speeds and/or revolutions.

Hitting the brakes while or before a pot hole or bump causes more damage than letting the suspension do its job. So, if your son hit a pot hole and braked hard before hand or during he removed the suspension from the equation.

I would look at your lower control arm to see if it is bent or the bushings destroyed - that would cause what you describe. If it checks out, I would look at the entire suspension including the shock itself.

[KyDave]

So here's an update:

This is the offending wheel. Seems to roll and drive OK, inner flange only, you can see where it scraped it's own clearance on the lower end of the strut. This is now rotated to the left rear so it's removed from the remaining problem:


I measured 0.020-.025" runout at the edge of the rotor and 0.010 runout at the hub flange. There definitely were "high" and "low" zones.


In a burst of creativity I realized that I DO have shim stock at home on Sunday afternoon! After about 4 assembly cycles and 2 test drives I got the edge of the rotor within 0.008" runout. 8/1000ths is better but you still don't want to drive it.....





So after about 6 hours of activity I ordered a new FAG bearing assembly and will learn how to install it.

[MoVolvos]

Just some thoughtful ramblings. Vibrations caused by out of balance or warped parts generally are more severe at higher speeds and/or revolutions.

Hitting the brakes while or before a pot hole or bump causes more damage than letting the suspension do its job. So, if your son hit a pot hole and braked hard before hand or during he removed the suspension from the equation.

I would look at your lower control arm to see if it is bent or the bushings destroyed - that would cause what you describe. If it checks out, I would look at the entire suspension including the shock itself.

Sent your thoughtful rambling to my boys. First and second year in college each have their own cars.

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[KyDave]

Yesterday I installed a new FAG hub-bearing unit and that DIDN'T fix it! I'm thinking that he bent the flange and continued to drive it, wearing the new Meyle disk unevenly. I'm taking that to be turned today and I've priced a cheap Chinese disk if it's too far out to be corrected.

[KyDave]

So, $10.60 to turn the rotor and it's fixed!

I'm thinking that after the hub was bent he kept driving until the rotor was worn into a wobble as well.