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Showing posts with label rotors. Show all posts
Showing posts with label rotors. Show all posts

Tuesday 5 February 2013

Repetitive Brake Problems

Brake Issues Occur Again n Again on Jeep



Regarding Jeep Grand Cherokee, Brake Problems
Q: My vehicle is 97 Grand Cherokee with 55k miles. Wee just replaced 4th set of  brakes put on including the original set. The rotors and pads were replaced each time. That equals a new set approximately every 14k miles. It is driven in very mild conditions around town with no heavy braking. It always has the same problem. The brakes feel like they engage and disengage as you come to a stop. It gives a slow pulsing sensation.

The first evaluation always offered is warped rotors. The problem is that immediately after a brake job you still can feel this problem. It’s milder at first and then becomes more pronounced as time goes on. I also know it has nothing to do with the rear brakes because if you use the hand brake to stop you don’t get the symptom.

The second theory is some type of ABS malfunction.This has been completely dismissed by the dealer.

Any idea what the problem could be??

A: How about checking the hub that the brake rotors are mounted on? Just the day of answering your letter we a had a Mercury Crown Vic in the shop that had a brake pulsation complaint. Diagnosis indicated that the front brake rotors were the problem. From what we were told, they had been a problem for sometime. As often as possible we’ll machine the brake rotors on the vehicle. When the equipment was installed on the vehicle to machine the rotors there was a problem. The computer, yes we used computerized equipment to perform this task, was at a loss. It could not calibrate itself properly, meaning it needed help from a carbon based life form (humans). Inspection found that the hub that the brake rotor set on was off by .003" of an inch. Now .003" of an inch is just about 2 hairs stacked. That’s not much you may say. But, in the world of brakes that adds up to a lot when you carry that line out another 4 to 5". My point is that no matter how many brake rotors are installed on this vehicle the brakes will always end up pulsating,, which could very well be the problem with your vehicle. They just have to look deeper. As for the Crown Vic, there is no silicone based form (computer) that can problem solve the way the carbon forms do.