Aurora40
10-05-2008, 02:26 PM
I believe runout is the term. Anyway, when I spin the front driver's side rotor, it will drag on the inside brake pad on one area of the rotor. There is clearly some variation in where the rotor is in relation to the caliper as the rotor spins.
So what I did was mark the area where it seemed to drag. Then I pulled the caliper off and took the rotor off. I spun the rotor on the hub 144 degrees (two lug nuts) and locked it down again with two lug nuts. I put the caliper back on. This is a fixed caliper, so it shouldn't have moved in relation to where it was previously. I then rotated the rotor and marked where it drags. The drag mark had moved about the same amount as I rotated the rotor.
This means it's not the rotor that has the variation, correct? Or is that not a valid way to check? Also, if it's not the rotor, what would it be, the wheel bearing? Or just the mounting area isn't flush or something? I guess I figured if the bearing were out of whack, it would still rotate properly, but the whole rotor might be at an angle when rotating.
I tried shaking the wheel top to bottom, and it didn't appear to have any movement.
From dealing with shims the last few weeks, I'd guess the runout in terms of how far it moves from the pad would be in the area of 0.01-0.02". Not a lot, but clearly visible. My guess is this wouldn't be hugely problematic, but I'd like to fix it.
So what I did was mark the area where it seemed to drag. Then I pulled the caliper off and took the rotor off. I spun the rotor on the hub 144 degrees (two lug nuts) and locked it down again with two lug nuts. I put the caliper back on. This is a fixed caliper, so it shouldn't have moved in relation to where it was previously. I then rotated the rotor and marked where it drags. The drag mark had moved about the same amount as I rotated the rotor.
This means it's not the rotor that has the variation, correct? Or is that not a valid way to check? Also, if it's not the rotor, what would it be, the wheel bearing? Or just the mounting area isn't flush or something? I guess I figured if the bearing were out of whack, it would still rotate properly, but the whole rotor might be at an angle when rotating.
I tried shaking the wheel top to bottom, and it didn't appear to have any movement.
From dealing with shims the last few weeks, I'd guess the runout in terms of how far it moves from the pad would be in the area of 0.01-0.02". Not a lot, but clearly visible. My guess is this wouldn't be hugely problematic, but I'd like to fix it.