Trailer brakes question on 2017 DOONAN charperal.

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by earnies2, Jul 31, 2021.

  1. earnies2

    earnies2 Medium Load Member

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    May 17, 2012
    Dedham, MA.
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    2017 DOONAN charperal if I set my trailer brake when I release them to move again it takes some time for them to release. I'm wondering if i have a bad valve? Or how to diagnose this problem
     
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  3. Goodysnap

    Goodysnap Road Train Member

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    Jul 12, 2017
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    First thing I would do is leave the brakes released and spray down air tanks and air line connections and inspect for leaks on the trailer. If the air bleeds off the emergency tank while setting, the tank needs to charge or refill before the brakes can release. The tank should be full, when you connect it should only signal air to release the brakes.

    Disconnect the red gladhand when charged and make sure that the emergency tank does not empty all its air out the gladhand.

    From there I would inspect the brake component for binding or sticking components.
     
    baha Thanks this.
  4. earnies2

    earnies2 Medium Load Member

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    May 17, 2012
    Dedham, MA.
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    Thanks for the fast reply when I stop today in a paved lott I will check that and report back. Again thanks
     
  5. earnies2

    earnies2 Medium Load Member

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    May 17, 2012
    Dedham, MA.
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    I checked thecait tank for water it had none. Then I removed the gladhsnd and its not leaking back out. In the process of getting my spray bottle the sky opened up and I was in the middle of an impressive thunder and lightning storm.... I will check for leeks and kinked lines next time I stop....
     
  6. earnies2

    earnies2 Medium Load Member

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    May 17, 2012
    Dedham, MA.
    0
    Update no leaking lines or tank.
    I followed the red airline back to the tank it goes into 3 valve that are stacked onto of each other or mabe its just 1 valve? The red line is connected to the valve and 2 red lines come off the valve and go to the cans... could this be the culprit?
     
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