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Vacuum issues

Discussion in '2nd Gen 4Runners (1990-1995)' started by Tannis133, Apr 6, 2021.

  1. Apr 6, 2021 at 5:54 AM
    #1
    Tannis133

    Tannis133 [OP] New Member

    Joined:
    Dec 1, 2020
    Member:
    #18237
    Messages:
    17
    Gender:
    Male
    Vehicle:
    1995 4Runner
    I'm getting complete vacuum lock on cold starts about once every 3 to 5 days. Brakes lockup and can't move. Have to warm the motor up then take the hose off the brake booster to release the pressure, which is new along with check valve that's inline.

    Any help would be appreciated
    V6 motor, 4x4
     
  2. Apr 6, 2021 at 1:02 PM
    #2
    Moon Landing

    Moon Landing AFFTC 1967/68 Eddies Air Patch

    Joined:
    Feb 4, 2021
    Member:
    #19563
    Messages:
    2,171
    Gender:
    Male
    First Name:
    Jer
    La Quinta, Ca. AKA "The Skillet"
    Vehicle:
    Moon Rock 4Runner
    Nam 68/69
    WAG - booster diaphragm may be bad.

    To test the booster function once the reserve is depleted. Hold moderate pressure on the brake pedal and start the engine. If the booster is working properly, the pedal will drop slightly.
     
  3. Mar 23, 2022 at 3:39 PM
    #3
    Tannis133

    Tannis133 [OP] New Member

    Joined:
    Dec 1, 2020
    Member:
    #18237
    Messages:
    17
    Gender:
    Male
    Vehicle:
    1995 4Runner
    Tannis,
    I have the same issue with my 95’ 4Runner. Two new boosters, new check valve. It will be fine for a week then start doing it. Mine will also do it on warm days if I turn off the motor and then turn it back on in about 5 minutes. Totally baffled. Did you solve your problems? Sure would like some help. Thanks
     
  4. Mar 25, 2022 at 1:21 PM
    #4
    dwb133

    dwb133 New Member

    Joined:
    Mar 25, 2022
    Member:
    #26303
    Messages:
    5
    Gender:
    Male
    I have the same issue with my 95’ 4Runner. Two new boosters, new check valve. It will be fine for a week then start doing it. Mine will also do it on warm days if I turn off the motor and then turn it back on in about 5 minutes. Totally baffled. Did you solve your problems? Sure would like some help. Thanks
     

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