Brakes acting up. Need advice.

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by Firemedic724, Dec 28, 2012.

  1. Firemedic724

    Firemedic724 New Member

    Hi All,
    I have a Chevy Silverado 2500 HD LT with 92,000 miles on it. Recently I have noticed that when coming to a full stop then releasing the brakes to go again it feels like the brakes are sticking. I have removed all of the calipers and checked for any pads hanging up. All pads and calipers move freely. I have also noticed that when at a stop if I push hard enough I can put the brake pedal to the floor. I am not using a great amount of force but enough to make it happen. Someone mentioned that this could be the hydro booster. Does anyone have any insight? How do I test the hydro booster?
    I appreciate any help.
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Here are the test instructions that came with my remanned hydro boost:

    1. With engine off, apply and release brake pedal 5 to 10 applications to deplete
    accumulator reserve pressure. With foot slightly pressing brake pedal, start engine.
    Pedal should drop and then push back against your foot.
    2. With engine running, turn steering wheel until lightly against steering stop. After
    5 seconds return wheels to the straight ahead position and turn engine off. Apply and
    release brake pedal. There should be at least one power assisted brake application.
    Start engine and allow accumulator to recharge before moving vehicle.
    3. Test drive vehicle. WARNING: Do not operate vehicle until brake and booster
    systems are functioning properly. There should be one power assisted application.

    Common problems and causes.
    1. Hard pedal - Slipping belt, low pump pressure, restricted system.
    2. Pedal stays down - Contamination in booster.
    3. Long pedal/no pedal - Possible brake hydraulic problem. Block master cylinder ports,
    recheck pedal action. If pedal is firm the problem is beyond the master cylinder.

    I would check out any rubber brake hoses on the truck. You would have to have someone press the pedal to the floor and you look around the truck. I suspect that you may have a rubber hose ballooning when you press the pedal to the floor.
  3. a.graham52

    a.graham52 Rockstar 100 Posts

    even in a brand new truck with hydroboost the brake pedal will go to the floor. totaly normal as long as nothing else is wrong (blown brake line etc). yes you should be able to pump the pedal up stiff with the engine off but as long as its running that pedal will travel.

    what do you thinking the brakes are "sticking"
  4. Dana W

    Dana W Rockstar 3 Years 500 Posts

    There may be some trash in the line blocking the fluid from backing off the caliper pistons. Does it seem to pull to one side? If so, that will clue you which side to blow out first.
  5. Firemedic724

    Firemedic724 New Member


    The brakes are not pulling to one side. They brake evenly. So should I flush the system out with new fluid? It sounds like you guys don't think it's the hydro booster?
  6. Dana W

    Dana W Rockstar 3 Years 500 Posts

    It's hard to say, but with that many miles new brake fluid certainly won't make it worse. Since the brakes stop evenly it is unlikely that both sides will be clogged with exactly the same amount of debris.

    It is possible that your caliper slide/retainer bolts and/or the pad slide area in your calipers can be dry/rusty/dirty. Where the moving parts rub need some sort of lube. There is high temp brake grease that you can apply to the slide bolts and the ends of your pads where they slide on the caliper. Some should be used when the pads are changed.
  7. j cat

    j cat Epic Member 5+ Years 1000 Posts

    the pedal to the floor with the engine running would indicate the master cylinder is failing. with the 92,ooomi and how old ??? 6 plus yrs ? I would replace all the brake fluid first. this would require to open the bleed screw and push back the caliper pistons fully then bleed out.. do not push back the pistons then open bleed screw as this pushes the contaminated piston fluid into the ABS contral valve section.

    if the brake effort does not improve after this then replace the master cylinder.

    sometimes the cal pistons will stick at a point in the wear of the brake pad material. I have found the rear piston on some to get bell shaped and stick. contaminated fluid will also cause the seals to swell, then the piston binding as well. it does not take much mineral oil to cause these type issues when brake fluid has this mineral oil get into it.
  8. a.graham52

    a.graham52 Rockstar 100 Posts

    just remember that even brand new trucks (atleast untill 2010, havent cared to check the newest ones) the pedal WILL go to the floor normally if the vehicle has hydroboost.

    i would still like to know why the OP thinks the brakes are sticking.

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