Changed rotors, more steering vibrating

[jlfarley]

I had really worn pads and warped rotors (at least that's what the mechanic said) Changed both, though the rotors really didn't look THAT bad.

With the old setup, the steering was a little wobbly. Now, I get this pulsating vibration when I brake. I've heard this is a problem with worn rotors, but these are brand new. What gives?

 

[Section_8]

did you brake them in with a good seating?

Otherwise, given the year of your car, it 'could' be an indication of worn control arms or bushings - these are put under more stress under braking, and are a common wear-and-tear on cars with 40k or more (sometimes less!). The braking could be showing off the worn suspension parts - or maybe they just need to be seated a little better? (The pads that is!)

 

[William330]

Are you sure when you are testing your new brakes, that
the pulsing is not coming from the ABS? Or does the pulsing
happen all the time (such as during light braking)?

The ABS will come on if you brake hard, and feel like a pulse.

Is it true that the BMW dealer will not machine rotors, but
insist the rotors are replaced?

 

[jlfarley]

I'm not really sure what seating the brakes is. My dad installed them for me, and he's pretty good with cars.

If I brake lightly, no pulsating. But when I brake normal, it does it. And it didn't do it before.

One thing, the front tires are a bit worn on the inside. Could this cause the problem?

 

[wood_e]

My alignment is off on my car. The fronts wear on the inside. It does create a vibrtation in my steering wheel when at speed, and braking. I'm sure my rotors aren't warped. Check your alignment.

 

[William330]

If the tires are worn on the inside, it's probably time to replace them anyway -- don't want to hydroplane in the rain.

But if it didn't pulse before the brake service, it's probably not the tires.

I remember seeing a few websites document the entire process to replace brake pads (with photos and all, for every step), perhaps Google around for that and see if you might have skipped a step.

 

[ManJestic]

don't want to hydroplane in the rain.

He's in San Diego, where in never rains...

Seriously though, did you use quality rotors? Did you clean the surfaces where the rotor and the hub attach? Did you clean the back of the wheels and properly torque the wheels?

 

[Kirby]

ManJestic brings up a good point.

If the wheels were put ON with an impact wrench, this is rumored to cause this type of problem. Torque spec is about 75 ft lb. If you don't have a torque wrench, use the wrench with car, and try to estimate putting 1/2 to 1/3 of your body weight into it.

Since you're trying to determine if this is the problem, I suggest this technique to ensure that everything is evenly seated and tightened:

- Always tighten the nuts in a star pattern, never sequentially in a circle.
- Tighten the all the lugs about only about 1/3 turn after they seat on the rim.
- Now torque them down.

 

[jlfarley]

Had the alignment done today, and while they didn't test it, they told me they think it may be a bad brake hose or caliper. Thing is, wouldn't this have shown up before the new rotors went on?