dirtypwntang

So it was time for new pads and rotors, and I figured I would change the rotors out for the cross-drilled and slotted variety from rotora. I'm full aware this isn't the best choice for performance, but I won't be tracking my car any time soon so I am not concerned with that. I used hawk hps pads.

My problem is that the rear brakes make a rather high-pitched whine, more audible and higher pitched at higher speeds. It become very audible when I actually apply the brakes.

I have considered that maybe it is just the rotors still breaking in, but it has been 1000 miles now.

I also thought that maybe the pads are lightly touching the rotors, but I don't think that would correctly explain the noise becoming LOUDER when brakes are applied.

As it comes from both rear brakes, I'm hesitant to say that both sides have a specific problem with, say, calipers.

I've pulled both assemblies apart and put them back together 3 times now.

My conclusion is that perhaps it is just in the way the rotors are shaped with the holes and slots and all? Maybe they cut the air in such a way that they make this noise?

Does anybody have any other input? Thanks in advance.

INTJ

How much did you back the piston? Did you use grease or glue on pads? Backing plates? Is there a metal wear tab on the noise shims or pad assembly?

Did you bed the pads to spec?

The holes and slots IMO suck. As you put better pads on the noise goes up exponentially. The other issues are just installation problems.

dirtypwntang

I applied a very very thin coat of grease behind the pads. But I've done the same on all my other cars with no problems like this.

Regarding the piston, I compressed it about as far as it would go. Could I have damaged it?

And yes, I know what the generally accepted opinion is on drilled rotors. I'll pick up a better set for if I decide to track my car, but for street use they are fine. To be honest, they ARE more asthetically pleasing.

The little noise indicator tabs are there, but not touching the rotor (new pads).

You think a little grease will do the job?

joey1320

i have had the same issue with Hawk pads twice before and after that i stopped using them. is just the material used on the pads, not "soft" enough and with more "metal" than needed, so is metal to metal which makes the noise.

if you get the brakes hot does it go away? mine did that also, after some hard stops the noise would go away and as soon as they got cold it would come back. after replacing the pads to EBC(green) the noise went away.