a couple months ago my brakes were making the car shake something vicious slowing down from 60+. i got the rotors turned, cause the guy at the shop said they still had 50k miles left in them. i put the rotors back on, along with new pads, and stopping was silky smooth for a month and a half. now, as of a couple weeks ago, the wheel is shaking coming down from high speeds again. what'* the deal? is there any way a rotor could be warped? are my alloy wheels buggered up from years of tightening my lugs with an air wrench (i just found out when i did the brakes that you're supposed to use a torque wrench and do them evenly)? help is appreciated.

You have warped rotors. Turning is only a temporary fix. You'll continue to warp rotors unless you somehow fix your wheels so the lugs are mating to the rim right, and use a torque wrench, following the procedure in Techinfo, Specifications.

If you have uneven torque on a Bonneville, you WILL warp rotors in time, especially hot weather. Once they're warped, turning will only buy you a very limited amount of time.

thanks for the info, i really appreciate it. so i'm gonna get some new rotors, but i have 2 questions: 1.do you think my 2 month-old pads are now screwed up and i will need new ones again? 2.do you recommend a brand of rotors? thanks.

-ben

Whenever you install new rotors you need to change the pads too. That way both mating surfaces are clean, and free of grooves. Grooves in the old pads will affect the braking performance if you reuse them with new rotors.

As for a brand of rotor... Contrary to most on here, I just use the cheapies from AutoZone or Advance. The $20 each rotors work just fine for me and I typically get 50,000 out of them before they warp. A lot of it depends on your driving habits (i.e. hard, fast stops, etc.)

Also, it'* a good idea to clean and put some new silicone grease on those caliper slide bolts so the calipers moves freely.

And don't forget to lube the back of the pads. I agree, 2 months on warped rotors would dictate that your pads are garbage. If it had been a week or two, simply scoring them with 60-grit sandpaper would work, but yours will be too far gone.

The rotors you buy will be based on your climate (heat in the summer) driving conditions (hilly or flat) and driving style (like me? Or like 'Ol Timer). Fill us in. If you drive conservatively, with a moderate climate, and no hilly driving very often, good 'cheapie' rotors should be find for you. But you should take some precautions.

1. Clean off the face of the hub with a stiff wire brush and some brake cleaner. Get all the scale, rust, and debris off.

2. Do the same to the back of the wheels, but use a BRASS brush for the aluminum wheels.

3. Make sure you de-burr any damaged lug sockets on the wheel from your impact wrench work.

4. Thoroghly clean all the lug studs, so that there'* no debris in the threads.

5. Put a drop of ANY kind of oil on each stud before installing the lugnut. This will help in achieving even, consistent torque.

6. Torque in the typical 'stagger' or 'star' sequence. First to 50 ft/lbs, then to 75 ft/lbs, then finally to 100ft/lbs. Don't use the cheapie torque wrench. Use a 'clicker'.

If you follow these steps, your rotors will have a much higher chance of survival.