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rotors keep warping

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Old 07-27-2008 | 03:19 PM
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Default rotors keep warping

A while back I replaced my front rotors with some brembo blanks because they were warped and it fixed the problem. It didn't take long and it started shaking badly again so i figured it is my rear rotors so i ordered a set of brembo blanks for the rear. to see if my rear rotors were bad, i slowly pulled the e-brake to see if it shook as i was rolling, it didn't so i'm thinking my rear rotors aren't warped after all. i took the tires off the front and spun my rotors and there was some resistance, but they still spun, i dont know how much resistance there is supposed to be. i'm thinking my front brakes are dragging, causing my front rotors to keep warping. do i need to rebuild my calipers?
Old 07-27-2008 | 03:52 PM
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So called rotor warp can be caused by a few things, the reasons I've encountered are poor bedding and simply bad rotors.

Basically poor bedding occurs when you try to use the brakes normally after install and your version of normal is hard braking. A few panic level or high speed stops and they are "warped".

Stocker LSx front rotors have warped on me despite a really good break in for the pads and material. Using brembo blanks now with stock pads for 2 years and 50k now and still going strong.

The break in method I use is slow downs 10-0, 20-0, 30-0 then 40-15 and 60-15 breaking. The brake pressure I apply is about 60-70% of full lock. A little more than normal easy braking but still off from kicking in the ABS. After that I drive around normally for a good 15 mins, stop and go and usually after such a brake in I'm able to do panic stop level braking or high speed 100mph slow downs ie track almost immediately afterwards.
Old 07-27-2008 | 04:02 PM
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I never really went through a process like that when i swapped my rotors, i was just easy on them for a while.
Old 07-27-2008 | 08:21 PM
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Try some different pads then, so far I've used hawk's HPS and AC Delco "Premium Ceramics".

To test if it's rotor warp to be sure, do a lite scuffing of the rotors with some sandpaper, 200 grit or less and also to the pads, rub them on concrete in a figure 8 pattern to scuff evenly. Then re do the bed in procedure. I did that a few weeks ago after I managed to glaze over my rotors doing a good 160mph to 40mph slowdown in really hot weather with 2 year old brake fluid in a short distance. I had to change fluid as I knew it felt off and the rotors had hot spots on it. Even then it wasn't warped, just lost some braking capability.
Old 07-31-2008 | 12:15 PM
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i finally took it to the shop and they tested new rotors with a screwdriver, where they put it on the rotor and spin it and see when it scrapes the rotor and they used the same rotor on the left as on the right and it was uneven on the right, but fine on the left(with the same rotor). you think my hubs could be warped or bent somehow?
Old 07-31-2008 | 02:59 PM
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Did you ever clean and regrease the caliper guide pins?

The rear ebrake is just a brake shoe that works on the inside of the drum part of the rear rotors. The rear ebrake doesn't effect the pads on the rotors.
Old 07-31-2008 | 09:45 PM
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Originally Posted by z28bryan
Did you ever clean and regrease the caliper guide pins?

The rear ebrake is just a brake shoe that works on the inside of the drum part of the rear rotors. The rear ebrake doesn't effect the pads on the rotors.
it turns out it was the rear rotors. he said the e-brake was dragging and it warped them. and yea, he told me that the e-brake was seperate today. after he fixed the ebrake, it engages with the lever at more of a 45 degree angle where it used to be more of a 90. still never figured out what was up with the passenger side hub, but it's obviously not enough to cause a problem.




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