Bleeding ABS

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Thread: Bleeding ABS

  1. #1
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    Bleeding ABS

    hi there,
    recently, I was replacing my brake's rubber hoses on my 97 Silverado. I got busy for while talking to a friend, and I did not remember to plug my brake's hose. when I came back, I notice my master cylinder was dry. Now I have super soft paddle and air in my ABS. I bled my brakes and tried so far:
    1. vacuum bleeding
    2. paddle bleeding
    3. pressure bleeding
    4. I have Snap On Mt2500 scanner, and I tried to access to ABS but my scanner does not support it, nor other scanners except Tech1.
    I still have air in ABS, so is there any other way to bleed my ABS without using Tech1??
    Thanks, Ivan

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    Re: Bleeding ABS

    Quote Originally Posted by Z28 Racer
    hi there,
    recently, I was replacing my brake's rubber hoses on my 97 Silverado. I got busy for while talking to a friend, and I did not remember to plug my brake's hose. when I came back, I notice my master cylinder was dry. Now I have super soft paddle and air in my ABS. I bled my brakes and tried so far:
    1. vacuum bleeding
    2. paddle bleeding
    3. pressure bleeding
    4. I have Snap On Mt2500 scanner, and I tried to access to ABS but my scanner does not support it, nor other scanners except Tech1.
    I still have air in ABS, so is there any other way to bleed my ABS without using Tech1??
    Thanks, Ivan
    Well unless you can find a scanner that will let you perform an ABS Bleed Procedure you will need a Tech2.

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    Re: Bleeding ABS

    I tried my friend's OTC scanner, but it did not have an access. I was thinking about hot wire the ABS's motor,then, bleed the brakes. what is your opinion on that?

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    Re: Bleeding ABS

    I think it would be safer to find a shop with a Tech 2 to do it.

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    Re: Bleeding ABS

    ABS Automated Bleed Procedure
    Important:

    Use the two-person bleed procedure under the following conditions:

    - Installing a new Electro-Hydraulic Control Unit (EHCU) or new Brake Pressure Modulator Valve (BPMV).

    - Air is trapped in the valve body

    Do not drive the vehicle until the brake pedal feels firm.

    Do not reuse brake fluid that is used during bleeding.

    Use the vacuum, the pressure and the gravity bleeding procedures only for base brake bleeding.


    Two Person Procedure
    Raise the vehicle in order to access the system bleed screws.
    Bleed the system at the right rear wheel first.
    Install a clear hose on the bleed screw.
    Immerse the opposite end of the hose into a container partially filled with clean DOT 3 brake fluid.
    Open the bleed screw 1/2 to one full turn.
    Slowly depress the brake pedal. While the pedal is depressed to its full extent, tighten the bleed screw.
    Release the brake pedal and wait 10-15 seconds for the master cylinder pistons to return to the home position.
    Repeat the previous steps for the remaining wheels. The brake fluid which is present at each bleed screw should be clean and free of air.
    This procedure may use more than a pint of fluid per wheel. Check the master cylinder fluid level every four to six strokes of the brake pedal in order to avoid running the system dry.
    Press the brake pedal firmly and run the Scan Tool Automated Bleed procedure (below 15,000 GVW) once, or run the Function Test (above 15,000 GVW) four times. Release the brake pedal between each test.
    Bleed all four wheels again using Steps 3-9. This will remove the remaining air from the brake system.
    Evaluate the feel of the brake pedal before attempting to drive the vehicle.
    Bleed the system as many times as necessary in order to obtain the appropriate feel of the pedal.

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    Re: Bleeding ABS

    I don't see how it can be done otherwise??

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    Re: Bleeding ABS

    Quote Originally Posted by GMCSonoma
    Two Person Procedure
    Raise the vehicle in order to access the system bleed screws.
    Bleed the system at the right rear wheel first.
    Install a clear hose on the bleed screw.
    Immerse the opposite end of the hose into a container partially filled with clean DOT 3 brake fluid.
    Open the bleed screw 1/2 to one full turn.
    Slowly depress the brake pedal. While the pedal is depressed to its full extent, tighten the bleed screw.
    Release the brake pedal and wait 10-15 seconds for the master cylinder pistons to return to the home position.
    Repeat the previous steps for the remaining wheels. The brake fluid which is present at each bleed screw should be clean and free of air.
    This procedure may use more than a pint of fluid per wheel. Check the master cylinder fluid level every four to six strokes of the brake pedal in order to avoid running the system dry.
    Press the brake pedal firmly and run the Scan Tool Automated Bleed procedure (below 15,000 GVW) once, or run the Function Test (above 15,000 GVW) four times. Release the brake pedal between each test.
    Bleed all four wheels again using Steps 3-9. This will remove the remaining air from the brake system.
    Evaluate the feel of the brake pedal before attempting to drive the vehicle.
    Bleed the system as many times as necessary in order to obtain the appropriate feel of the pedal.
    I did the first part, but I do not Tech2

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    Re: Bleeding ABS

    Quote Originally Posted by GMCSonoma
    Use the vacuum, the pressure and the gravity bleeding procedures only for base brake bleeding.
    I did not know that you can not use those methods when you have air in ABS. thanks for the advice.

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    Re: Bleeding ABS

    You're gonna have to have the tech2. GMC Sonoma's procedure also needs a tech2. You need it because it opens ports to allow the brake fluid to flow (I honestly don't know what ports it opens, but you can hear them open when the tech opens them). They'll remain shut unless the Tech's bleed procedure is activated. All late-model GM vehicles this way. That's a shame since brake bleeding use to be so easy. It shouldn't take for a shop to bleed the brakes so my guess is it'll set you back around 30-45 dollars.

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