Stock Rotors Pulsating
Thread Starter
Racer
Joined: Jan 2005
Posts: 335
Likes: 0
From: New York
Stock Rotors Pulsating
I'm getting a pulsation all the time when I brake, no matter how softly I try to come to a stop. When I purchased my 2000 coupe a couple of months ago the dealer replaced all the pads but did nothing to the rotors. They are now suggesting that I cut the rotors, but I am afraid to degrade their performance. Should I have them cut and will it eliminate the pulsing? The car has 31K miles on it.
Drifting
Joined: Feb 2005
Posts: 1,332
Likes: 0
From: Columbus OH
"cut" the rotors?...Ithink they mean "turn" or at least, "grind down."
basically, they just grind them down flat again; the reason they pulse now is because they're warped from heat...a common problem.
It will not degrade performance at all, but you can only turn them once; if they warp again you'll need to replace them.
They *should* replace the pads too, though the dealer prolly won't. Ask them to re-grease the slide pins on the calipers as well....something else MY dealer never did on brake jobs and can lead to calipers sticking...and heat..and warpage..starting a vicious and expensive cycle.
basically, they just grind them down flat again; the reason they pulse now is because they're warped from heat...a common problem.
It will not degrade performance at all, but you can only turn them once; if they warp again you'll need to replace them.
They *should* replace the pads too, though the dealer prolly won't. Ask them to re-grease the slide pins on the calipers as well....something else MY dealer never did on brake jobs and can lead to calipers sticking...and heat..and warpage..starting a vicious and expensive cycle.
Pro
Joined: Apr 2002
Posts: 726
Likes: 2
From: Denver CO
Best way to do it is on the car. Doubt your dealer has the equipment, though. When on the car, all the little imperfections in runout are compensated with the turning of the rotors....of course if you ever take them off, you have to be sure you put them on the right way or you'll really experience pulsing. Runout has been a problem for a long time on C5s and turning the rotors off the car will solve the problem for a short period of time, but if there is runout cause by other components (bearings, axles, etc.) it will only be a matter of time before the disc wears odd due to the runout and magnifies it enough to result in the pulsing. The runout can be addressed with shims. A company used to make them (may still) and they were approved for use by GM in their stealerships to address the runout issue. You might check into them.
Melting Slicks
Joined: Jan 2002
Posts: 2,096
Likes: 0
From: Size Does Matter CA
Waste of time and money to turn them. Buy Napa rotors for $27.00 a piece. Paint the hats to the color of your vette.
I turn the rotors once by the dealer $200.00 and some change, lasted for about 2 months.
I turn the rotors once by the dealer $200.00 and some change, lasted for about 2 months.
Safety Car
Joined: Jan 2005
Posts: 3,896
Likes: 26
From: Manchester - Political correctness is tyranny with manners.
Originally Posted by iteachflyin
I'm getting a pulsation all the time when I brake, no matter how softly I try to come to a stop. When I purchased my 2000 coupe a couple of months ago the dealer replaced all the pads but did nothing to the rotors. They are now suggesting that I cut the rotors, but I am afraid to degrade their performance. Should I have them cut and will it eliminate the pulsing? The car has 31K miles on it.
Safety Car
Joined: Jan 2005
Posts: 3,896
Likes: 26
From: Manchester - Political correctness is tyranny with manners.
Originally Posted by iteachflyin
I'm getting a pulsation all the time when I brake, no matter how softly I try to come to a stop. When I purchased my 2000 coupe a couple of months ago the dealer replaced all the pads but did nothing to the rotors. They are now suggesting that I cut the rotors, but I am afraid to degrade their performance. Should I have them cut and will it eliminate the pulsing? The car has 31K miles on it.
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Yours is a common (and misunderstood) complaint. The Rotors AREN'T warped. They've got a residue built up from the break pads. (Take a runout gauge to them and mic them for thickness and you'll find they're true and flat) I'd gone through two full sets on the 98. (Heat cracking on the first set, plus pulsation, and pulsation on the second set) Since going to slotted rotors on our 98, the problem hasn't returned.
FWIW, turning the rotors on a sportscar is an excercise in futility. The Rotor's mass is used to dissipate heat and prevent warping. If you remove material, all you'll do is cause it to warp quicker.
FWIW, turning the rotors on a sportscar is an excercise in futility. The Rotor's mass is used to dissipate heat and prevent warping. If you remove material, all you'll do is cause it to warp quicker.
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Drifting
Joined: Feb 2005
Posts: 1,332
Likes: 0
From: Columbus OH
Originally Posted by RocketSled
Yours is a common (and misunderstood) complaint. The Rotors AREN'T warped. They've got a residue built up from the break pads. (Take a runout gauge to them and mic them for thickness and you'll find they're true and flat)
Originally Posted by RocketSled
FWIW, turning the rotors on a sportscar is an excercise in futility. The Rotor's mass is used to dissipate heat and prevent warping. If you remove material, all you'll do is cause it to warp quicker.
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Originally Posted by cadams
It could be heat, it could be residue. No way to know unless we physically see them. In my case, the rotors were definately warped, they had blue spots all over them; one of the front rotors was not fully releasing due to a rusty slide pin.
Last set were the grooved rotors and they've been great for 25k miles or so.
Melting Slicks
Joined: Mar 2005
Posts: 2,534
Likes: 118
From: Columbia, SC
Thread Starter
Racer
Joined: Jan 2005
Posts: 335
Likes: 0
From: New York
Thanks a lot everyone. I won't turn 'em. I'm gonna look into the NAPA rotors, sounds like a good deal. I've got a non-dealer Corvette specialist that I can work with. I'm sure he can do this for me. I'm worse than all thumbs when it comes to fixing stuff. I drive 'em and fly 'em but leave the fixin' to the pro's.
Racer
Joined: Sep 2004
Posts: 384
Likes: 0
From: Sarasota FL
I am in the same situation. I am getting the NAPA rotors and am going to paint the hats. I have a brake shop that will put them on for $30. I will have to remind them to regrease the slide pins. The part numbers for the fronts are 86701 and 86700.
