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Warped? Rotor Q

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mattman, Jan 10, 2002.

  1. mattman

    mattman 1/2 ton status

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    This is kinda long. This pertains more to my BII but my Jimmy is doing something similar.

    Over the summer, whenever I hit the brakes it felt like I had a warped rotor (or two) up front. They always squealed and sometimes felt like they were grabbing when braking. You could creep with the brakes on and feel it grab on the high spots. Well, when the cold weather set in a couple of weeks ago, the problem really lessened. However, yesterday when it was real warm, my brakes were doing it real bad again. In fact, it felt like the more I used them the worse it got. It felt almost like I was out of pad and the rivets were up (there not, brand new pad)

    Before it got cold, I put a new set of pads on (couldn't hurt) and tried to break the glaze on the rotors. However, I had spots on the rotors that looked like rust but wouldn't sand out. I had it on both rotors even the one I installed new about 2 years ago.

    Now to the question. I had read somewhere that one thing that will warp a rotor is hard panic stops. It does something to the metal in the rotor when the rotor is real hot and clamped.
    Is this true? If so, can it be turned out? Or is my only alternative new rotors? I'm curious because I don't want to go through all the trouble of pulling and turning my rotors just to find out I have to go through it all again and put on new rotors.

    Sorry about the long post and thanks for any help and input.

    90 GMC Jimmy, 350 TBI, 700R4, 32's, D.O.D.
    84 Bronco II 216,000 smoking and going.........
     
  2. Esteban86K5

    Esteban86K5 1/2 ton status

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    Your brakes are basically pulsating. I had this problem when i first got my blazer and I replaced the brakes without turning the rotors. All I did was had the rotors turned and Presto!!! No more pulsating. I've never heard of rotors being warped by hard braking. If that was the cause I'd be replacing my rotors every year.[​IMG][​IMG]

    <font color=blue>It's easier to teach a child than to fix an adult.</font color=blue>

    <a target="_blank" href=http://community.webshots.com/user/geltyone>Webshots Pics.</a>
     
  3. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>Rotors get warped from constant heating and cooling, like driving around town for a few miles, stopping for a few hours then getting back in and doing it again. You never get fast enough to cool them and your using the brakes more around town than on the highway. Find a dial indicator and measure the runout, if the runout isnt too excessive you can have the rotors re-faced. Dont change pads without re-surfacing the rotors
     
  4. Executioner

    Executioner 1/2 ton status

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    If two of the lug nut are tight say 60 lbs./ft. and the others are even tighter say 120lbs./ft.
    Any heating and cooling under those conditions will warp the hub and rotor.
    And usually can't be turned with much sucksses.
    Good luck
     
  5. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>Good point, if the lugnuts are too tight or unevenly tightened, the rotors will not be re-usable
     
  6. m j

    m j 1/2 ton status

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    caliper guide pins in less then perfect shape will hang and drag cooking the rotor
    I have seen more "siezed" calipers with guide pins being the culprit then hydraulic piston siezed, one reason good brakes are 4 piston

    formerly 77chev
    still a jerk though
     
  7. mattman

    mattman 1/2 ton status

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    Thanks for all the responses. Sounds like I just need to bite the bullet and get some new rotors. I know the lug nuts were torqued right - I torque them everytime with a torque wrench. Also, it primarily gets used for city driving - rush hour city driving, which in this town is a lot of braking. Only reason I changed the pads was it always felt like the rivets were up and they weren't (checked this on a regular basis) and I thought a new set might help (didn't have much to lose) but they haven't.

    90 GMC Jimmy, 350 TBI, 700R4, 32's, D.O.D.
    84 Bronco II 216,000 smoking and going.........
     
  8. RESTORE89

    RESTORE89 1/2 ton status

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    before you replace tehm take them to a shop, and they can tell you if they can safley turn them and get them true again. i ahd the same prob with an old vette, and i took them off and carried them to a brake shop, and they said they had already been turned before and if they turned them again they would be to thin to be safe, so i repalced. but if yours are not to bad then save the cash and have them turned. most shops wont charge anything to just check
    good luck
    chris

    It needs a bigger motor.
    what's in it now?
    doen't matter it NEEDS A BIGGER MOTOR
    89 350tbi/700r4h/np208/4.11's
     

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