Is it wearing brakes fast? Also, this may sound simple, but make sure the backing plate behind the rotor isn't touching the brake rotor. They rust, bend. And sometimes rub. Now, since it is speed related, it has to deal with the rotation of the wheel. Therefore, we can dismiss bushings. Make sure the warning sensor on the pads isn't touching, make sure the caliper is releasing. If they are all good, then we have to consider a wheel bearing. I recommend checking to make sure the caliper is working / releasing. You mentioned a grinding noise when braking which sounds like the brakes are metal to metal, but you said you replaced them 2 times. Thus, I assume the pads are good. Safely raise and support the front so you can spin a wheel. Identify which wheel is making the noise, then sipn the wheel and have a helper hit the brakes. The wheel should stop and then be moveable when the brakes are released. If you can't spin it for sometime after releasing, then you have a caliper that is sticking or it could be a bad rubber brake hose to the caliper. Inside the hoses, they break down over time. When you force fluid (with the brake pedal) through them, the caliper can respond. However, when released, the insides of the hose will not allow the fluid to return / releas. As a result, you end up eating brake pads because the caliper can't release. To check if it is a hose, do this. If after releasing the brake pedal the wheel takes time to spin again, open the bleeder valve on the caliper. What that does is release pressure to the caliper regardless of the brake hose. If the wheel then spins, replace the hose. If it is still sticking with the bleeder open, then the problem is in the caliper.
NOTE: If it is the old caliper side, spray a lot of penetrating fluid on the bleeder. They can break. If it does, you will be replacing the caliper.
Sorry to be so wordy. I'm just trying to be specific, give you some things to check and I'm trying to be as specific as I can. Let me know if it helps or if you have other questions.
Thursday, September 15th, 2011 AT 1:48 AM