Suspension Springs, Shocks, Brakes

Strong vibration under medium to heavy braking

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Old Jan 31, 2009 | 12:44 AM
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LSJ PUP's Avatar
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Strong vibration under medium to heavy braking

Looking for possible explanation for this. The car shows similar vibration that you would undergo when your rotors are warped, but at much stronger level. Checked the brake pads and they have plenty of life. Rotors are gm drilled and slotted. They are 1 year and 4 months old as are the pads. Newest mod to the car are the sportline springs. Springs have been on for a few months now. My only thoughts here are that the stock shocks have gone bad. I beat on the car around corners fairly often. We checked the motor and tranny mounts and they look fine. Any thoughts?
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Old Jan 31, 2009 | 12:46 AM
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I'm thinking the rotors are warped. Even though they are drilled and slotted if you brake hard enough for long enough they're bound to have problems eventually. Only other thing I could think of is if you got new wheels/tires they are out of balance (and yes, tires can be out of balance and you just have to drive to break them in)
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Old Jan 31, 2009 | 12:54 AM
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I would diagnose this as warpped rotors!!!
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Old Jan 31, 2009 | 01:41 AM
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Don't think it's a tire balance issue as the vibration is only present under breaking at medium to high levels. I was really leaning toward warped rotors but because of the severity of the vibration, I began to think there was a different problem. My oem rotors warped and a vibration was present, but nothing of this magnitude. I was be completely surprised if GM would put there name of a better rotor than oem, but worse in terms of it warping to this degree over such a short period of time. Not ruling this out by any means though.
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Old Jan 31, 2009 | 08:17 AM
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Originally Posted by LSJ PUP
Don't think it's a tire balance issue as the vibration is only present under breaking at medium to high levels. I was really leaning toward warped rotors but because of the severity of the vibration, I began to think there was a different problem. My oem rotors warped and a vibration was present, but nothing of this magnitude. I was be completely surprised if GM would put there name of a better rotor than oem, but worse in terms of it warping to this degree over such a short period of time. Not ruling this out by any means though.
check your pads if the pad srface is shiny they are glazed, take a sanding block with some 320 grit and remove the glaze + get rid of drilled rotors...
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Old Jan 31, 2009 | 08:23 AM
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Originally Posted by qwikredline
check your pads if the pad srface is shiny they are glazed, take a sanding block with some 320 grit and remove the glaze + get rid of drilled rotors...
THANK YOU!
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Old Jan 31, 2009 | 08:27 AM
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serioulsly sounds like warped rotors
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Old Jan 31, 2009 | 08:34 AM
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Originally Posted by mrsilent13
serioulsly sounds like warped rotors
x2..
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Old Jan 31, 2009 | 08:47 AM
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Yea, my GM drilled and slotted rotors warpped on me. Both rear one's... they really suck LOL. I and just waiting for the pads to wear out and then I am putting Power Slot's on. Same thing with me though, Medium to Heavy braking is when I get the Vibes
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Old Jan 31, 2009 | 09:03 AM
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It is DEFINATELY, 100% CATAGORICALLY ROTOR WARP!!!!!!!! A dial indicator will reveal for sure.
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Old Jan 31, 2009 | 09:09 AM
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also check the abs system that would make the brakes pulse and shake under all braking my 06 ss/sc did it
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Old Jan 31, 2009 | 09:32 AM
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Originally Posted by BoostinLSJ
also check the abs system that would make the brakes pulse and shake under all braking my 06 ss/sc did it
That's a good point. I would also check that. Maybe it's just the ABS kicking in unnecessarily.
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Old Jan 31, 2009 | 09:35 AM
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Originally Posted by BigTizzle903
That's a good point. I would also check that. Maybe it's just the ABS kicking in unnecessarily.
theres a big difference in feel between those.


ABS feels like ur brake pedal pulsating, consistently, and usually only under hard braking.



warped rotors= vibrations, car vibrates not just pedal. its annoying and u can DEF tell the difference if u have ever felt ur ABS kick on.
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Old Jan 31, 2009 | 01:02 PM
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Originally Posted by qwikredline
check your pads if the pad srface is shiny they are glazed, take a sanding block with some 320 grit and remove the glaze + get rid of drilled rotors...
bada bing bada boom
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Old Jan 31, 2009 | 02:24 PM
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I guess I'll have them cut after I check the pads. Of the problem comes back after that down the road, which it will, I'll replace them. There should be a disclaimer when you buy these rotors, something to the tune of; the rotors will warp in a little over a year because they suck.
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Old Jan 31, 2009 | 02:41 PM
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There is a diclaimer right above the parts counter. You just cant see it when they are bending you over on the price. I payed $300 for these pos rotors. GM lets me down again LOL
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Old Jan 31, 2009 | 02:42 PM
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Originally Posted by shadowfaxss
It is DEFINATELY, 100% CATAGORICALLY ROTOR WARP!!!!!!!! A dial indicator will reveal for sure.
I agree excpt its not likely they are warped.(put that in your collective pipes and smoke it)

Originally Posted by LSJ PUP
I guess I'll have them cut after I check the pads. Of the problem comes back after that down the road, which it will, I'll replace them. There should be a disclaimer when you buy these rotors, something to the tune of; the rotors will warp in a little over a year because they suck.
There is, its called research. On this site and on all quality brake rotor company sites, you will almost NEVER see drilled rotors billed as a true performance rotor, and you will see many knowledgeable recommending to aovid them like the plague unless youre a show car.
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Old Jan 31, 2009 | 02:58 PM
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Those drilled metal rotors are more for show than for go. I think most of those rotors came with a disclaimers saying not for track use. Cracks will develop around the drilled hole, especially on low quality disks.
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Old Jan 31, 2009 | 04:22 PM
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Guys, they are not warped.

Any other suggestions?

Qwik: Thanks for the suggestion we'll try that.

Last edited by AlphaJaguar5; Jan 31, 2009 at 04:45 PM.
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Old Jan 31, 2009 | 07:21 PM
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Originally Posted by AlphaJaguar5
Guys, they are not warped.

Any other suggestions?

Qwik: Thanks for the suggestion we'll try that.
Alpha buddy happy to help. I was gonna say "snow in the wheels" as you are a semi pro hockey player and may be the hockey rinks are unplowed, but then i said to my self: "Self, Corey lives in FLORIDA" Ooops....
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Old Jan 31, 2009 | 09:55 PM
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Originally Posted by Maven



There is, its called research. On this site and on all quality brake rotor company sites, you will almost NEVER see drilled rotors billed as a true performance rotor, and you will see many knowledgeable recommending to aovid them like the plague unless youre a show car.
What about slotted rotors?
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Old Feb 1, 2009 | 01:03 AM
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It almost sounds like pad imprinting, sometimes called hot spots.

Have you been running fast, then hard on the brakes as you hauled down hard to a dead stop? Like a stoplight? Did you keep pressure on the brakes, to hold the car in place? (Is your car an auto?)

If you get the brakes hot enough, and come to a complete stop still applying heavy pressure on the pedal (without letting the car roll a little,) some of the brake pad material can literally fuse to the rotor resulting in an uneven surface. This can cause subsequent braking vibration, and not always show up as runout on a dial indicator.
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Old Feb 1, 2009 | 01:25 AM
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Originally Posted by Dave7417
This can cause subsequent braking vibration, and not always show up as runout on a dial indicator.
Ive never seen a car with a rotor related pulsation that had rotors that measured within spec.

If the problem is caused by the rotors, youll be able to measure it.
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Old Feb 1, 2009 | 01:40 AM
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I'm leaning toward it being the pads as qwik is suggesting. (Thanks by the way in case Corey didn't pass that along) The rotors look perfect and I don't see or feel any of the glazed ridges that I observed on my OE rotors. Granted I'm not a human dial indicator.
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Old Feb 1, 2009 | 09:10 AM
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Originally Posted by LSJ PUP
I'm leaning toward it being the pads as qwik is suggesting. (Thanks by the way in case Corey didn't pass that along) The rotors look perfect and I don't see or feel any of the glazed ridges that I observed on my OE rotors. Granted I'm not a human dial indicator.
u did gauge the rotors correctly right??

im going to say 99% of the time by looking/feeling the rotors you will not notice anything.
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