New GXP rotors grinding
07-19-2009, 06:27 PM
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New GXP rotors grinding Hey guys,
not looking for a diagnosis here, just want to see if anybody has run into this. My front brakes were pulsating, the rotors were warped. I went to go resurface them, but they were under spec. So I warranteed them and put on new ones (gotta love the GM Certified Used Car warranty!). I also put new pads on too because they were making a crunching noise. So I've had them on for a day or so and when I make tight right hand turns in a parking lot, I hear a grinding from the LF wheel. The rotor is getting scored on the outside face. So I took it apart a few hours ago and the rotor is grinding on the caliper bracket. It looks as if the rotor was made wrong because the rotor is not centered inside the caliper bracket opening. I took the rotor off and verified that all my hub mounting surfaces and caliper mounting surfaces were clean.
Anybody run into this before? Perhaps I just got a messed up rotor, its an OEM one, not Delco. I know there isn't much room for error because these rotors dont have much clearance inside the caliper bracket opening. I could shim the bracket and correct the problem, but thats not the proper way to fix this.
I'm gonna try pulling the RF rotor off and fitting it on the LH side to see how the offset looks.
Weird!
not looking for a diagnosis here, just want to see if anybody has run into this. My front brakes were pulsating, the rotors were warped. I went to go resurface them, but they were under spec. So I warranteed them and put on new ones (gotta love the GM Certified Used Car warranty!). I also put new pads on too because they were making a crunching noise. So I've had them on for a day or so and when I make tight right hand turns in a parking lot, I hear a grinding from the LF wheel. The rotor is getting scored on the outside face. So I took it apart a few hours ago and the rotor is grinding on the caliper bracket. It looks as if the rotor was made wrong because the rotor is not centered inside the caliper bracket opening. I took the rotor off and verified that all my hub mounting surfaces and caliper mounting surfaces were clean.
Anybody run into this before? Perhaps I just got a messed up rotor, its an OEM one, not Delco. I know there isn't much room for error because these rotors dont have much clearance inside the caliper bracket opening. I could shim the bracket and correct the problem, but thats not the proper way to fix this.
I'm gonna try pulling the RF rotor off and fitting it on the LH side to see how the offset looks.
Weird!
07-19-2009, 09:59 PM
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Interesting, I had the same exact issue with my front left rotor after replacing the pad & rotor. I used hawk pads & a duralast brand rotor. Well the rotor didn't seem to be rubbing up against the caliper, it seemed like it was just making contact at the top of the pad. Eventually it was so bad that the wheel would bind REAL BAD when backing up and making right turns. Took it to the dealer and they found that they had to replace the hub assembly and the problem was solved.
07-20-2009, 08:26 PM
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Get an OEM one, the aftermarket ones don't have the same quality. Not saying that the OEM ones are that great anyways, lol. www.gmpartsdirect.com I can get the part # tomorrow.
So I figured out the problem. GM Technical assistance couldn't even figure it out, they told me it sounds like a bent caliper bracket! Get this, my car has the upper bolt for the LF hub missing from the factory! Thats real safe! When I would make right turns, the top of the hub would flex out just enough to let the rotor rub on the bracket. Never noticed it before because my rotors were too thin.
Had to overnight the caliper bracket that got scraped up from the rotor. Gotta pull off the LF hub tomorrow and run a tap thru the hole with the missing bolt to get the rust out of the threads and put a new bolt in. Then I gotta resurface the brand new rotor to get rid of the gouge from the caliper bracket.
This kinda weird stuff only ever happens on my personal cars, never customer cars! lol
So I figured out the problem. GM Technical assistance couldn't even figure it out, they told me it sounds like a bent caliper bracket! Get this, my car has the upper bolt for the LF hub missing from the factory! Thats real safe! When I would make right turns, the top of the hub would flex out just enough to let the rotor rub on the bracket. Never noticed it before because my rotors were too thin.
Had to overnight the caliper bracket that got scraped up from the rotor. Gotta pull off the LF hub tomorrow and run a tap thru the hole with the missing bolt to get the rust out of the threads and put a new bolt in. Then I gotta resurface the brand new rotor to get rid of the gouge from the caliper bracket.
This kinda weird stuff only ever happens on my personal cars, never customer cars! lol
