I recently put a set of Detroit Axle drilled and slotted rotors on my Monte. Since they have been on, I have noticed a noise that I can only describe as a "flutter." When I drive by a wall where the sound is reflected back at me, it makes me think of the days of sticking a playing card or Hot Wheels track tab in the spokes of my bike.

It's not a metallic sound, like a clip making contact with the rotor, or anything like that. I pulled off all the wheels to make sure a wire or something isn't rubbing against anything, but I found nothing.

Thinking the pads might be bad, I changed the Detroit Axle pads out for Powerstop Evolution, but the fluttering sound remains. When I apply the brakes, the sound slightly increases as the pads make more contact and gets lower when I release... so it has to be the effect of the pads over the holes and slots in the rotor. When I search for information on this, the only noise I see people talking about is screeching or squeaking.

Is this a normal thing with drilled/slotted rotors? Or is it possibly a bad drilling job or another flaw in one or more of the rotors? The sound seems to come from both sides, but it's too hard to tell while driving. I had these type of rotors on another Monte and never noticed this problem... but they were Powerstop instead of DA. Relevant?

I'm about ready to just go back to solids.

 

Have you already bedded the pads? Wondering if there's a bit of a machining "lip" on some of the cuts that are causing the pad to skip across when they hit it. Bedding the pads properly should knock that down retty quick though.

I'd be all for going back to blanks though.

 

That's probably what I'm going to do.

 

Mine have always done that. Ive been thru 4-5 sets (power stop) since I had my '02, theyve always made that sound. Actually, I put the Detroit Axel brand on my Mom's Equinox and those did the same thing.

 

That's what I thought might be the case. I never noticed it on my other Monte, but there were enough other noises going on with that car that I didn't notice.

Thanks for the replies!