Brake Grinding Noise

chefdennis · Dec 10, 2008

Chevy / GMC Van Owners. Ok the brake pads are at least 50% or more, the rotors are fine, the front hub bearings are not bad, but there is a grinding noise in the front that sounds like metal to metal when braking, and it is at the worse just as the van comes to a stop.

Had it all apart monday night , everything looks good, but the noise is still there... Glazed over heated pads?

Any of you had this issue in the past?

It is a 2005 1 ton extended 3500 GMC CV. Any info would be aprreciated.

It is coming from the front, if i use the parking brake to stop the van, there is NO noise.

davekc · Dec 10, 2008

If it is metal on metal, it can only be the pad hitting the rotor or a part of the caliper is touching the rotor somewhere. If they have been messed with, it is possible the wear indicator got a little bent and that is grinding the rotor.
After that, I have no clue.

fastman_1 · Dec 11, 2008

Did you pull the pads out and look at them? The inside Pad wears faster than the outside pad, at least it does with my 03

OntarioVanMan · Dec 11, 2008

running heavyweight will glaze over the pads but grinding noise?

you said you had it apart? Pads not cracked/broken or pad starting to separate from the steel?

piper1 · Dec 11, 2008

Depending on who made the pads, sometimes the "squealer" that is supposed to tell you the pads are worn out is set to contact the rotor with as much as 50 % of the pad remaining. I run Delco pads on my GM stuff and at install, the first thing I do is bend the squealer back so it hits when the pads are really worn out. The grinding, might be the squealer hitting the rim of rust that you get on the very outer edge of the rotor face.

OntarioVanMan · Dec 11, 2008

piper1 said:
Depending on who made the pads, sometimes the "squealer" that is supposed to tell you the pads are worn out is set to contact the rotor with as much as 50 % of the pad remaining. I run Delco pads on my GM stuff and at install, the first thing I do is bend the squealer back so it hits when the pads are really worn out. The grinding, might be the squealer hitting the rim of rust that you get on the very outer edge of the rotor face.

your correct Piper..the ridge on the rim of the rotor made by the pad, the squeeler can rub against that....

chefdennis · Dec 12, 2008

Yes everything on the FT was torn apart. Calipers removed, pads taken of the calipers, rotors inspected. Everything was good, still more the half the pads left.

I removed the rear tires only and looked at the pads from all available angles and they looked good also, but i didn't tear the calipers off.

I swore the noise was coming front the front. When i used the emergency brake to stop the van, no noise. Now i have worked on ford 4 wheel disc in the past, (more then a few yrs ago) but never a GM 4 wheel brake system. I "assumed" (and we all know what that does) that the pads were applied when the emergency brake was applied, WRONG, they have a seperate "shoe" system inside the hub of the rear rotor.

So aftet talking to a friend at a Chevy dealership and checking TSB's there, I tore the rears apart. The caliper floats on 2 pins, much like the front, but not the same in the the pin doesn't screw into the braket, it also floats. Well one pin had frozen on the rt rear wheel. This system also as 2 piston calipers, when the pin froze, that let the caliper become stuck on and angle, while wearing the pad uneven, (not enough for me to see at this point), it let the lower edge of the caliper hit the lower edge of the caliper face where the pad is applied. There was the noise!

So a new set of rear pads later, all fixed.

Thanks for all of your responces. If I had done the inspection as I SHOULD have to begin with, id have found it the 1st time. But it was night, cold and i was doin it with a buddy that has a keg of beer in his garage all the time, so you can see me situation!! Dumb, dumb, dumb!!