Brakes locked up

Discussion in 'Lifted & Offroad Suspension' started by zebra308, Apr 22, 2009.

  1. zebra308

    zebra308 Rockstar

    This is my first post and I'm hopeing that someone here can tell me what the hell is going on with one of my trucks.

    A little history..
    The truck is a 2006 GMC 3500 Sierra flat bed that I bought new. The truck only has 35,000 miles on it.

    Only one problem with it since we've owned it, the HVAC resistor went bad and was replaced under warranty this past December.

    We now have a real problem..It usually presents itself when the brakes are applied. the pedal gets really hard and the brakes won't release. I think it's related to the antilock system? I haven't taken it to the dealer yet as the warranty just went out in Dec. of 08.
    Any help would really be appreciated.
    Thanks in advance.
  2. zebra308

    zebra308 Rockstar

    I guess no one has had a problem like this...Just an update to the issue.

    I took the truck to the dealer last week to get their opinion of what it might be? Needless to say the brakes were working fine when I brought it in( no lockup condition).

    They tested the ABS system and the brake system. According to the dealer, all systems are working correctly. They want to replace all of the brakes and rotors at a cost of approx. $ 800.00. (WOW)

    I was out of town when that call came so I didn't get to talk to the service tech myself. He explained to my foreman that they suspect the calipers slides are dirty or corroded. I would accept that answer if it were one caliper acting up, but all four?

    I'm going into the shop today and take pics of the calipers and rotors, and while we have the wheels off we're going to lubricate the slides. There's better than half of the original pads still on there and the rotors are not scored.

    Hopefully that will fix it. We'll see.
  3. zebra308

    zebra308 Rockstar some pics of the pad contact points on the calipers. You will notice that there's a stainless steel clip that the ends of the pads ride on....and NO CORROSION.

    I think the dealer was trying to take me for a ride?

    We lubricated the clips and used the truck the other day. With a skid of concrete...3,600 lbs...on the truck we had no issues with the brake system.
    I still think it's related to the ABS and it's malfunctioning causing the brakes to lock down on the rotors.
    We'll see?

    Attached Files:

  4. grimreapersshadow

    grimreapersshadow Rockstar 100 Posts

    what kind of booster do you have vacuum powered or hydraulic?
  5. zebra308

    zebra308 Rockstar

    It's the hydroboost type..standard for the 3500 series of trucks.
    We've been using the truck every other day now and everything seems OK.
    It did not need new I was told by the dealer. I hate it when they try and sell you something you don't need.
    The truck stops fine. I still think it's an ABS issue.
    We'll see?
  6. grimreapersshadow

    grimreapersshadow Rockstar 100 Posts

    yeah a dealer works like that and yeah that does sound like a abs problem the more i think about it most i seen a hydraulic system do was just stop pumping and there would be no petal/brakes at all
  7. zebra308

    zebra308 Rockstar

    So far so good. we just lubed the calipers...although I don't really think it was necessary.
    Everything works ok now
  8. zebra308

    zebra308 Rockstar

    Well...after 2 months of trouble free braking...using the truck every day, the problem has surfaced again!

    I will take it to the dealer again and see what they have to say about it this time. There were suggestions of some contaminant in the fluid, but I don't think that's the problem. This time only the 2 front brakes were locked up.

    One interesting thing though. When I open the cap on the power sterring unit...there's an escape of air. just as if you opened a bottle of soda. Not a lot...just a little" phsst".
    I've never had that happen on any vechile I've owned. Maybe we're on to something?
  9. grimreapersshadow

    grimreapersshadow Rockstar 100 Posts

    the abs unit could have a small leak not enougth to see but it could be sucking air into the system some where but i would definatly let the dealer know about it maby they can do a good pressure check on evey thing

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