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Brake Problem on 2004 Silverado

Discussion in 'Lifted & Offroad Suspension' started by BowTieFan1, Mar 7, 2010.

  1. BowTieFan1

    BowTieFan1 Member

    I moved this thread from Brakes, Tires, and Suspension section to General Q&A. I am still looking for help with this. Any mechanics on this forum?

    I am having trouble trying to fix a low and soft brake pedal on my 2004 Silverado. I have already replaced the master cylinder, flushed and bled the brake lines at all four wheels. Still the pedal is low and soft.
    Does anyone know what it could be? There is no loss of brake fluid any where. The master cylinder reservoir is not losing fluid. My truck has disc brakes on all four wheels, and the pads are in good shape. I do not think there is anything wrong with the calipers because the truck does not pull to one side.
    To engage the parking brake, I have to push it down a lot more than usual.
    So, I am not sure if the problem is more likely the booster or the calipers. Can anyone help?

    BTW, sometimes the pedal will be high and firm, then sometimes it will go back to low and soft. If I pump the pedal they will get firmer. When at a stop, I can feel the pedal slowly sinking.
  2. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Pumping the pedal sounds like either ai in the lines or a bad booster.
    Bleed the system correctly starting at the bypass valve then working from the next farthest out caliper (rt rear) next closest and so on until you've bled all the calipers.
    It might take two trips around to get all he air out.
  3. BowTieFan1

    BowTieFan1 Member

    I forgot to mention that I also took it to a mechanic 2 times to have the lines bled. The problem came back after both times from the mechanic. He says he found no problems. :neutral:
    The brakes will feel high and firm one day, then another day they will be low and soft. I do not have to push the pedal hard to get braking, it just goes down too far. I thought that if a booster goes bad, it would make you have to push the pedal much harder.
  4. 99'HEARTBEAT

    99'HEARTBEAT Epic Member Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    I also had a soft brake pedal,went it was time to put on New brake pads.......I went with SSBC's Stainless Steel Slotted Rotor's and added Russell's Stainless Steel Braided Brake lines.......I now have a firm Brake pedal and also less pedal travel.In short my brakes now are a Huge Improvement over the stock Brake's.

    Link,

    http://www.summitracing.com/parts/RUS-672430/
    Last edited: Oct 20, 2012
  5. Blackmax200

    Blackmax200 New Member

    You bench bled the M/C before you put it on, didn't you? If not, you may have forced air into the AB S. If any fluid dripped out of the lines during the swap, same thing.

    Short of taking the truck to a dealer to have the system bled using the Tech II scan tool, you could find a safe place to exercise the ABS system.

    A loose gravel road or wet parking lot will work. Go about 30 mph and hit the brake pedal firm and hard. You should feel the pedal pulsate , which indicates that the system is working. Do this 4 or 5 times, then go back and bleed the brakes in the proper sequence. What you are doing is trying to get any air that could posdsibly be trapped in the ABS hydraulic unit to pass through and on out to the wheels.

    If this does not work for you then the only option is to have a dealer, or a shop with a Tech II, bleed it with the scan tool that cycles the ABS on the lift while bleeeding.

    Hope this helps
    Last edited: Mar 8, 2010
  6. BowTieFan1

    BowTieFan1 Member

    Blackmax,
    yes, I bench bled both M/C`s before I mounted them back to the booster. The mechanic bled the the lines at the wheels afterwards. I do not know how or what method he used though. And the problem came back both times.

    99`Heartbeat,
    replacing my brake pads and calipers have crossed my mind, but the pads are not even half way worn yet.

    I`m thinking it is one of three things. 1. Air is still in the system. 2. The calipers are going bad. 3. The booster or check valve is bad. :neutral:

    I am taking the truck to the dealer in the morning. I`ve tried all that I know.
  7. 99'HEARTBEAT

    99'HEARTBEAT Epic Member Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor


    I should have been more clear in my above reply, I put on new Rotor's and Pads....But after still had a Soft Brake pedal and by putting on SS Braided Brake lines, I No longer have that Soft Mushy Brake Pedal. This New Brake Setup, is a Big Improvement over the Stock Brake Setup!!.....
    :glasses:
    Last edited: Jun 12, 2013
  8. Loggerhead Mike

    Loggerhead Mike Rockstar 100 Posts

    let us know what they found
  9. Dave D

    Dave D New Member

    Henry, I have the same truck, just blue. I'm having issues with the breaks as well. The break lines rusted out and had to be replaced last fall. Then, just within the past month, the calipers in the front started sticking, but only occasionally, usually on the highway after about 15 minutes of driving. If I park the vehicle and let things cool down, then the calipers seem to stop sticking. I thought it was the calipers, so i replace the fronts along with the pads. It was okay for several days and now they were sticking again today! I also have the squishy pedal that is sometimes firm and sometimes not. I don't know what to do next, maybe the master cylinder is the issue. I also bled the breaks several times after I did the calipers... very frustrating and costly!
  10. mikecrawfish8

    mikecrawfish8 New Member

    im haveing same problem with my 2004 4x4. did you find a cure

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