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Brake pedal goes to the floor?

Discussion in 'Trucks and Trailers' started by dfor, Dec 6, 2000.

  1. dfor

    dfor LawnSite Senior Member
    Posts: 821

    1998 GMC K-2500. Lately the pedal has slowly been catching closer to the floor. Now it is all the way and I've almost got no brakes. Someone told me that it was probably that the rear brakes need adjusting. One section of the brake fluid container is empty. Even with adding a little fluid, no luck. What do you guys think?
  2. John DiMartino

    John DiMartino LawnSite Silver Member
    Posts: 2,555

    Glad im not in front of you.Just cut a hole in the floor and mount up some steel plates on your boots,then stop freddy flinstone style.LOL. If you dont know much about brakes or arent mechaincally inclined.,I think its time to take it to a shop.Brakes are nothing to experiment with.If have done repairs before and can tackle it,you should already know where to look.I suspect you either have a blown wheel cyl. or a rusted thru brake line.Being the truck is in the north east and is 12 yrs old, iwould be ready for a big repair bill.Because you waited so long and just because its an old truck,the whole system is probably in need of repair.write me privately and ill go over costs and what is needed.
  3. dfor

    dfor LawnSite Senior Member
    Posts: 821

    John, thanks for the reply. The truck is a 1998 though, not a 1988. I thought that it could be a wheel cylinder also.
  4. John DiMartino

    John DiMartino LawnSite Silver Member
    Posts: 2,555

    Sorry,I thought it was an 88.It's a wheel cyl or the ABS unit,more likely a cyl.Is there any wet drips running off the rear brakes onto the inside of the tires.
  5. Fierospeeder

    Fierospeeder LawnSite Member
    Posts: 51

    After you fill up your fluid, you have to pump the pedal a few times to build up the pressure.

    Check for leaks at your master cylinder where your resevoir is at. there are lines that go down to a proportional valve then splits to the front and rear. The front sometimes has a splitter and goes to each wheel. The steel lines are connected to a rubber hose and go into your caliper. Rubber hoses are common to crack and leak fluid.
    The rear does the same also, a steel line runs back to a splitter and goes to each drum. The drums can leak on the inside from the cylinders. Look for a wet spot inside your wheels using a flashlight, or follow the steel line under your floorpan to see any wet spots.
  6. bandit_36

    bandit_36 LawnSite Member
    Posts: 49

    If you have air in the ABS system you'll be better off taking it to your local dealer or qualified mech. who knows about the kelsy-hayse 4WAL system that you have on that truck. It specialized equipment to bleed the ABS unit, a lot of brake fluid (up to 2qts.)& just the right cuss words to get all the air out & I know them all. I've been a GM tech. for 15yrs.

    Good Luck

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