: Shaking when braking



johnnyrako
12-28-12, 12:14 AM
My car has only 8,000 miles and at speeds of 60 mph + my steering wheel vibrates when lightly braking. This is an obvious warped rotor issue and the dealer states they don't feel it and if it was warped rotors its not covered under warranty.. I find this hard to believe.... Can someone please explain this?
So far, every condition/concern I have identified, the dealer tells me there is nothing wrong.
Apparentky, I have a $70k Teflon car..
My headlights fog-up and it's OK because they only fog up a little... AKA- Safety Concern
My engine runs very rough at idle, when in gear and stopped at a light. It's a known issue but its OK because there's no CEL or codes. AKA- cost avoidance and BS; probably a fowled spark plug but GM won't pay for diagnostics and repair...
Its odd that my wife's Mercedes ALWAYS gets fixed with any concern that is brought up... My Porsche and Viper also get fixed anytime I've taken them to the dealer but GM is in denial and doesn't fix things because their defects are little defects that are within acceptable limits.

vincentm
12-28-12, 12:57 PM
Warped rotors possibly due to a screw up on reinstalling the calipers during a brake job. Im experiencing the same thing, in the market with R1 concepts for new rotors, calipers, and pads.

johnnyrako
12-29-12, 01:31 AM
The car had 8,000 miles not 80,000 miles and it hasn't had a brake job. There shouldn't be any reason for me to consider installing aftermarket rotors since the car is barely broken-in.......

Kingoftypos
12-29-12, 04:44 PM
What are the tire's psi at? Does it match up with the label on the door sill? I never had a display for psi on the radio, so I don't know how accurate they are. Personally I would check with an actual gauge at each wheel.

Of course you have to check the psi when the tires are cold. Meaning the car hasn't moved for at least 6 hours.

KOT

Submariner409
12-29-12, 07:24 PM
Rotors are machined from cast iron - they don't "warp", but they do develop spots of pad resin deposits from city/slow driving. Take the car out to a deserted country road and do several aggressive stops from 65-70. Do not hold the brakes at stop - drive away, do it again, and then drive for at least 5 miles to cool the rotors. Holding the brakes after stops when new or after an emergency stop is a sure way to develop a nasty brake shudder during normal stops.

Don't believe me - get out of here and into several brake/pad/rotor sites and read up on how to use brakes. www.ebcbrakes.com is a good place to start - U.S. , automotive, pads, rotors, and read all the links.

vincentm
12-29-12, 09:39 PM
Ok, warping, bad term, thanks for the info Sub as always:

http://www.ebcbrakes.com/automotive_product_news/what_causes_brake_vibration_steering_wheel_flutter .shtml

Kingoftypos
12-29-12, 09:43 PM
Where did the term "warped rotors" come from? Was there a time where they actually did warp because they were made out of lesser quality metals?

KOT

Cadillac Cust Svc
12-29-12, 10:46 PM
johnnyrako1,
If you would like for us to look into anything further on this with you (either following up with your dealerhsip or helping you locate another dealership to get a second opinion), please contact us either via private message or email at katie_lucille@gmexpert.com (include your name and contact information, the last 8 digits of your VIN, and a summary of the situation).
Sarah (Assisting Katie), Cadillac Customer Service

Submariner409
12-30-12, 11:06 AM
Where did the term "warped rotors" come from? Was there a time where they actually did warp because they were made out of lesser quality metals? KOT

In road racing events - particularly in large prototype sports car events - the front brake rotors will visibly glow red hot during hard (HARD) braking for switchback and slow chicane turns. The cars brake rapidly from 120++ to < 25 and back up to speed. This sort of use destroys rotors and can actually heat the cast iron so hot that it begins to distort - the rotor "warps' - changes shape. It is not uncommon to perform a complete brake change (in less than 1.5 minutes) about halfway through the 24 hour LeMans or the Daytona Rolex 24 Hours (the old Daytona Continental of the 60's and 70's). But our cars don't give that sort of abuse to brakes so the term "warp" has been applied to brake judder and vibration due to pad deposits.

In most, not all, cases a series of controlled aggressive stops from 60 - 70 with immediate driveaway will clean the rotors - until the next month of city driving screws them up again. In severe cases, the act of burnishing the pads and rotors can actually cause smoke and stink. Normal.

johnnyrako
12-30-12, 11:04 PM
I appreciate the feedback but I've never had to do that on any if my other performance vehicles and they never had shuddering in my steering wheel when I brake. I absolutely love the car but these little issues and the dealer not fixing things is beyond irritating...

Submariner409
12-30-12, 11:27 PM
Do yourself a favor and at least find and study several websites on braking, brakes, and brake maintenance.

As I posted before - try the rotor burnishing procedure before you stick your head in the sand with "I've never had to ....". I'm not spouting hearsay or ill-founded opinion - the procedure is a well-documented well-used maintenance trick.

At the very least, you would have the info and experience as further "ammunition" for your dealership repair efforts.

spearfish25
07-14-13, 05:45 PM
Rotors certainly do warp. While pad deposits will cause a steering wheel vibration, overheated rotors can warp and do the same. Go look in a cooking forum and you'll see all kinds of issues with warped cast iron pots and pans. Brakes get far hotter.

Jaxle67
08-24-13, 05:10 PM
Not to get into a warped rotor argument I have found in several cases of mine that loosining of the lugs car jacked up of course and retightening them according to specs with a torque wrench in a criss cross patern has elimimated a lot if not all of the shuddering under braking. Just a suggestion
Jesse

Submariner409
08-24-13, 05:17 PM
Are you posting to get information on the OP's question to Cadillac Customer Care ? This warranty thread has been dormant for almost 8 months.