Warped Brake Rotor?

1263 Views 13 Replies 6 Participants Last post by Slipgate, Feb 6, 2015

wayfst

Discussion Starter · Feb 3, 2015

I have a shaking or vibration when applying the brakes from a moderate to high speed. The front brakes were done by the dealer 2 - 3 years ago but only 7 or 8 thousand miles, maybe less put on the car since then. The dealer says warped rotors are causing the vibration which means they probably didn't turn them when they did the brakes.

Is it better to replace the rotors or can I have them turned, assuming they have never been turned and if they have that there is enough left to turn? It seems I read somewhere that it is better to just replace them on a cadillac but I can't find that thread so don't know if I read that or not.

Any issue's with O'rielly or Autozone rotors? I did read on this forum that all rotors are made in China. Probably at the same plant...

What about the pads? There should be alot of pad left (haven't looked yet), if so is it alright to reuse them or might warped rotors have damaged them in some way that is not easily visible?

Thank you for any and all advice. This is my folks car and I want to do it right (unlike the Cadillac dealership)

Brian

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Submariner409

· #2 · Feb 3, 2015

Passenger car - and most other - rotors are cast and machined from gray iron. It does not warp.

Rotors can be skimmed to remove surface irregularities and brake pad resin deposits, or you can look through any of several aftermarket brake manufacturer sites to find a suitable set of daily driver rotors and pads (usually ceramic) that will give strong, reliable, smooth, quiet service.

Look at www.rockauto.com and www.placeforbrakes.com.

Study the Tech Tips for how-to information - there are several specialized procedures you must follow for these cars - like screwing in the rear caliper pistons.

ALL hub, wheel and rotor mounting surfaces must be absolutely clean and true. No loose/worn front suspension parts/bushings. Lug nuts torqued to 100 lb/ft sequentially in a star pattern.

For brake rotor construction, breakin and care - study the tech papers in the Automotive sections of www.ebcbrakes.com and http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths . Both companies are HUGE brake disc manufacturers.

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Submariner409

· #4 · Feb 3, 2015

From the 2002 Seville GM service manuals:

NOTE: Whenever the rotor has been separated from the wheel bearing flange, clean any rust or contaminants from the wheel bearing flange and the brake rotor mating surfaces. Failure to do this may result in increased lateral runout of the brake rotor and brake pulsation. (In this case, "lateral runout" is vibration.)

See also GM/Cadillac TSB #01-05-23-001B of 01/31/2008

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Submariner409

· #6 · Feb 3, 2015

Stuck front caliper(s) on these cars is rare. Better bet is a torn front center motor mount along with wear on the several other engine and cadle mounts as well as worn/loose front sway bar links and mounting bushings.

ANY slop in any of those powertrain mounts is an invitation to vibrations.

Don't overlook tires that have broken radial belts or tread misalignment.

Last resort, after rubber mount checks and hub/rotor/wheel cleaning and alignment checks, is a Hunter Road Force wheel balance procedure.

Bottom line: These cars are hypersensitive to front end - powertrain - mounting and alignment faults.

EDIT: Front center motor mount - covered in here and Tech Tips a million times - Get a trusted assistant, open the hood. Start the engine at idle. You stand next to the driver's side fender, looking at the engine/radiator relationship. Have your assistant firmly hold the service brakes with the left foot, place the stick in D and accelerate the engine to 1200 rpm or so. If the engine torques - rotates - more than 1" toward the firewall the front center mount is toast. Replacement is a mechanical aptitude test .............

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Submariner409

· #9 · Feb 4, 2015

In many - if not all - cases, "dirty" rotors can be cleaned of deposits and winter rust by performing several aggressive stops from 55 - 60 mph, driving away immediately after each stop and finally letting the rotors cool for 2 - 3 miles of normal driving after the cleanup stops. This procedure will get the rotors HOT - not to worry - those rotors are designed to run cherry red during aggressive road course work. That's one reason they're made of cast iron.

Hot rotors ??? Common.

https://www.google.com/search?q=nig...JrKG4erNsiZgMAH&ved=0CCIQsAQ&biw=1366&bih=618

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Submariner409

· #12 · Feb 5, 2015

Just like brake shoes and drums, it all wears out as it's designed to do. Rotors are NOT forever - by any means. Normal maintenance items.

That's why, for every mile you drive, you put $0.29 in the bank to pay for car ownership costs.

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