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JOHN aka Eauto
JOHN aka Eauto, The Car Guy
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When applying brakes, there is a loud air leaking sound coming

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When applying brakes, there is a loud air leaking sound coming from the Brake Booster under the dash. After the air leaks for a second, there is a vibrating noise (sounds like an air compressor) coming from inside the engine compartment. It runs only for a second or two, and then the cycle repeats.

Brakes function normally at highway speeds, but not at idle (Which is when the above problem occurs).

Does my Power Brake Booster need to be replaced? And if so, which specific parts? (i.e. just the Brake Booster, or the Diaphragm Drum too?

Vehicle: 2003 Chevy Silverado 1500 2wd 4.8l V8.

the diaphram is internal of the booster, The brake booster will need to be replaced if its leaking

Vacuum Brake Booster Replacement

Removal Procedure

Caution: Refer to Brake Fluid Irritant Caution in Cautions and Notices.

Note: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.

  1. Apply the park brake and block the wheels.
  2. graphic

    1. Remove the brake master cylinder. Refer to Master Cylinder Replacement (Vacuum Boost) Master Cylinder Replacement (Hydraulic Boost).
    2. Remove the vacuum hose from the brake booster check valvegraphic

      1. Remove the pushrod retaining clip (4) from the brake pedal stud (1).
      2. Remove the stop lamp switch (2) and the pushrod (3) from the brake pedal stud graphic
        1. Remove the 4 vacuum booster mounting nuts.
        2. Remove the vacuum booster.
        3. Remove the gasket from the booster and discard.

        Installation Procedure

        1. Install the gasket to the booster.
        2. Install the vacuum booster.

        Note: Refer to Fastener Notice in Cautions and Notices.

        1. Install the 4 vacuum booster mounting nuts.
          • Tighten the nuts to 36 N.m (27 lb ft)


            1. Install the pushrod (3) and the stoplamp switch (2) to the brake pedal stud (1).
            2. Install the pushrod retaining clip (4) to the brake pedal stud (1).
            3. Install the vacuum hose to the brake booster check
            graphic

            1. Install the pushrod (3) and the stoplamp switch (2) to the brake pedal stud (1).
            2. Install the pushrod retaining clip (4) to the brake pedal stud (1).
            3. Install the vacuum hose to the brake booster check valvegraphic


              1. Install the master cylinder. Refer to Master Cylinder Replacement (Vacuum Boost) Master Cylinder Replacement (Hydraulic Boost).
              2. Release the park brake and unblock the wheels.
Customer: replied 6 years ago.

looks it to me......good luck....if this was helpful please hit accept

it says with jc3 or jc4 brakes. your option sticker is stuck inside the glove box....verify that there is a jc3 or a jc4 on that sticker. if either of those is on there its correct

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