Thread: need your brake knowledge / input

Because of vibrations at the front ,At 54,460 klms ( car had steel winter rims a good winter tires on at this klms period ) I had the 2007 grand prix 3.8 n/a ,front rotors replace at gm dealer .I also had them put on new pads and cleaned and lubed sliders etc etc.

Appears the rotors were just warned down enough to pass as warranty claim and sliders were seized a bit ,so inside pad on drivers and passenger brakes wore more then the outsides pads.
They put stock rotors on so they say , but they put ceramic pads on versus factory semi metallics. This all done under factory 60,000 klms warranty .

In between those 54,460 KLMS replacements / repairs and the the 60,000 klms , I would say 1 to 2,000 klms ,it next went in for front brake work again ,for eeking / creeking noise at front wheels likely the calipers again , that they even noticed also .

So at 60,000klms they re-cleaned and re-lubed the slides , back of pads and anything esle required. And we had them put back on good aluminium rims and summer tires .


Now at 60, 865 ( bit less during trip time ) we took it on a 2 hour trip up and back from a place call liverpool.
Every time we had to slow down from 80 , 90 , 100, 110 klms to take a turn off or break behind someone ,the steering wheel , pedals, front end bascially etc vibrated / pulsating like crazy , you could both feel and hear the vibration and pulsating.

So just talking to the service advisor , he said they are likely just going to turn down the rotors. I am thinking turning rotors down already that only have about 6,000 klms on them and that before the trip they were cleaned and lubed front and back.

Now from what I ever learned with my gagt and maybe other vehicles or listen to others , that if you turn down a rotors that vibrate like that you likely are just turn down a warped rotor. And by turning down warped rotors , that does not get rid of the warp , and it will come back.

This is the part number for the rotors # 18048698, do you guys think it is the part number for factory original equipment rotors for the 2007 GP 3.8 N/A 4 wheel disc.

I had the same exact problem with my GP. The front rotors were so worn that replacing them was the only option...Pads were replaced with ceramic. The vibrations went away for a while but then returned with a vengence!

After troubleshooting I discovered that the outer tie-rod end and wheel bearing on the passenger side were bad...replaced them. After driving the car for about a week the vibrations were less but still noticeable when braking at high speeds. When slowing to a stop I noticed the brake pedal pulsating which would suggest warped rotors.

I removed the front rotors again and took them to the shop. They said that the rotors were fine, no warp.

At this point the I moved my attention to the rear of the car. The rear rotors looked good but I decided to take them to the shop. Mechanic at the shop put the rotors on the turning machine; he said that both of the rotors were badly warped. After removing 0.020" they were straight. I put the cut rotors back on the car with carbon metallic pads and everything is fine. I didn't know that rear rotors would warp that bad! Warped rear rotors will make it feel like the vibrations are coming from the front of your car.