All, I put new power slot drilled and slotted rotors and new pads on my SS two weeks ago. Ever since when I go to stop from 40mph or higher I get a roaring noise that sounds like a plane engine spinning down. I took it to my mechanic and he said the hubs look good and that he thought the pads just needed to bed in. That was over a week and a half ago. It still hasn't improved. Could the brand new rotors be warped already? What else do I need to check?

 

initally, did you bed-in the new pads per instructions ?

 

Well cross drilled and slotted rotors can give some noise, I'd check to see if they are directional and whether they are mounted on the correct sides. Directionally slotted rotors if mounted on the wrong side will carry on something fierce.

I'd think by now you're bedded in, but you may be glazed on the friction surface, you might want to pull the pads and check them. What brand of pads and rotors are you running?

 

Centric pads and power slot rotors. I did bed them in.

 

How can I tell if the pads are glazed by looking at them?

 

Here's a four step checklist you can use....

1. Examine the brake pads visually. You can tell if the pads are glazed if you can run your finger over the surface and it's smooth. A shiny or crystallized look to the brake pad is also an indication that it has glazed over.

2. Listen for a squeaking or squealing sound when you press down on the brakes. This is one of the most common signs that the brakes are smooth due to overheating and have become glazed.

3. Listen for a continuous scratching or squeaking sound even when you don't press on the brakes. In this case, the brake pad may be consistently dragging across the rotor while you're driving. This continuous friction causes overheating that results in a glazed brake pad.

4. Test your vehicle's stopping power, when driving, in a safe location, such as an empty parking lot. If you experience difficulty with stopping the car, such as a delay in slowing down the vehicle or vibrations coming from the wheels, this could be a sign of glazed pads.

And here's a photo of a glazed pad, hope this helps.

 

Thanks a ton. What's the fix if they are glazed?

 

Well back in the olden days with non-metallic friction materials you could sometimes sand them back to a fresh surface, inhaling a ton of asbestos in the process(why more old mechanics don't have cancer still baffles me). I believe that the newer metallic, semi-metallic, and ceramic friction materials can only be thrown out and replaced with new pads.

If anyone here knows of a way to safely bring glazed pads back, please chip in.

 

sanding belt......

 

If the old TSB regarding "warped" rotors could be recalled from the dead, I believe GM suggested sanding for glazed pads (if they are off the vehicle).