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HELP 1998 k 2500 brake problem

Discussion in 'Chevy Trucks' started by golfmanres, Oct 15, 2007.

  1. golfmanres

    golfmanres Senior Member
    Messages: 150

    I have a 1998 k2500hd 5.7 ext cab short bed. I have rear durm breaks and disc front. I chaged the front calipers last year and never was able to get it blead right. The ABS light is always on, i was told this is because there is air in the lines. How do i fix this? Do I bleed the brakes when the engine is on?

    Second problem,
    At about 45mph i push on the brakes and the whole truck shakes really hard, then it stops around 30mph. What is causing this? I was told it could be the tires are out of balance, the allignment, But I dont have any shaking when at high speeds 70-75. When I make turns there is no shaking either. And it is only when i push the breaks? Is it the front or rear breaks causing this? Please help me.
  2. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    First of all do you have the repair manual? It may have a way to make the ABS light blink a code for what's wrong. You might have to bleed the ABS controller circuit or circuits. Did you change the rotors or check them for run out? If they have been machined they can warp when close to the limit on thickness. Check and make sure your ABS sensors are all pugged in and seated in their holes / holders. The ABS sensors are real fragile, be cool with them they have a real thin skin. Unplug them and put Dielectric grease in the plugs to protect the connections.The power brake assist system that runs off the power steering may be a problem too. There is a post earlier this year on them. Use the SEARCH function on the gray line above to see if there is more posts on brakes.
    I am A Ford guy but I have worked on or helped on plenty of G.M.'s
    Most of the parts and systems are the same from brand to brand.
  3. golfmanres

    golfmanres Senior Member
    Messages: 150

    So i went today and took the tires off and checked the rotors, drums. Everything looked ok. They are newer rotors. About 5k miles on them. When i change the pads i put new drums on always. I didn't find the sensors that you spoke of. I think I am going to take it to the shop and have them power bleed them. I am going to look at geting new tires and see if that helps the problem next.
  4. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    The sensors should look like the old condensers cans on ignition distributors. They fit in a holder that's over a toothed ring which turns with the rotor / spindle shaft. They sense when one wheel is slowing down quicker then the others. The ABS module then reduces pressure to that brake. This keeps the wheel from locking up. From what you have said I would bet it's the power booster that's the problem. Like I said search it and I bet the posts will help you figure it out.
  5. aulen

    aulen Junior Member
    Messages: 16

    Could it be the ABS causing the shudder? Blead the system as well as you can (can be difficult to get all the air out of these). Try a vacuum system if you can get your hands on one.

    See if you can get the ABS light to go out and then see if it still has the shudder.
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If you changed the calipers and it hasn't been right since, then more than likely you didn't get it bled. I'll bet the air is in the ABS module. You need to bleed these Kelsy-Hays ABS systems in a very specific manner if you suspect air in the ABS module (Read: they can be a real pain!). That's probably why you never got all the air out. Start with the bleeding procedure and re-bleed the system before spending money on parts you may not need, especially pertaining to the shudder you spoke of having too...Air in an ABS equipped brake system can cause all kinds of strange braking problems..it very well could be related to the ABS..Your gonna need a pro shop to do the bleed procedure and make sure they scan the ABS code BEFORE THEY DO ANYTHING ELSE! This is very important for diagnosis but if they're a good shop, they'll know that already.
  7. ed39

    ed39 Senior Member
    Messages: 120

    the shaking your feeling could be your rotors wraped. even tho they are brand new rotors are made cheaply and suck these days. have your tires checked to make sure if they are balenced. that would caus the steering wheel to shake. no need to throw parts at it
  8. Sydenstricker Landscaping

    Sydenstricker Landscaping PlowSite Veteran
    Messages: 3,882

    Hey I got the same shudder prob on my 2000 K2500. I know for a fact that the front rotors are warped. My 94 K2500 had the same issue, new rotors and shudder is gone. If the rotors are new, you may be able to get them machined vs replacing them, if they are within factory wear specs. I am replacing the rotors on mine this weekend. PITA job, but it makes the truck stop 100 times better.
  9. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Go to a bigger Library and get a Professional Repair manual ( Motors, Chilton ) and look at it for the procedure to bleed the ABS controller. Most do have bleeder screws on them. Most of the parts store repair manuals will not have the procedure for this. Go back and read my posts. I was certified in brake repair when I got out of High School. I know a bit about brakes. Replace all the springs and sliders / bolts when you do brakes.Clean up the contact / slide points and use high temp brake grease on them. If you get grease or stuff on brake surfaces when you reassemble the parts, clean it off with alcohol or brake cleaner.Clean machined parts and new parts before you install them. Machine drums and rotors when the system has seen many miles between brake surface replacements. Run out and out of round will cause brake pedal pulsation and poor overall performance of the braking system. Many miles on rotors and drums will polish the working surface of the brakes and diminish the efficiency.
  10. RAZOR

    RAZOR Senior Member
    Messages: 343

    I was having the exact same problem with my 1995 k2500. It was the front wheel sensors. It is very common problem. Clean them up and I bet that will take care of the shudder and the ABS light should go out. It sounds like the ABS is coming on when it should not.