389 Peterbilt air leaking out of exhaust port

Discussion in 'Trucks [ Eighteen Wheelers ]' started by KittyKicker, Oct 22, 2019.

  1. KittyKicker

    KittyKicker Light Load Member

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    Dec 27, 2015
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    I have a 2015 389 Fitzgerald glider. I noticed tonight that when I released the tractor brakes I could hear air continuing to flow somewhere. It is coming out of the exhaust port on the firewall. This truck has always had a delay between pushing in the knob and the brakes actually releasing, but now the air won't stop blowing out of the exhaust. The truck will hold 120 psi at an idle even with the air coming out of the exhaust, but I can't figure out why it is doing this now and I don't want something to happen while my driver is on the road. Thoughts?
     
  2. S M D

    S M D Road Train Member

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    Mar 15, 2012
    sacramento ca
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    more than likely brake chamber. Release the brakes chock the wheels and listen to the brake chambers. And shut the truck off while the wheels are chocked and brakes are released

    otherwise follow the sound. Could be the fitting got loose behind the dash. It is a glider after all.
     
    KittyKicker Thanks this.
  3. KittyKicker

    KittyKicker Light Load Member

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    You know, I've hear a lot of people talk down about the gliders, but this truck has given me 430,000 plus miles of very low maintenance operation. It really has been a great truck, good fuel mileage, excellent oil analysis results, really no major problems to speak of. Well worth the purchase.
     
    Claytonbigsby Thanks this.
  4. Ezrider_48501

    Ezrider_48501 Road Train Member

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    Apr 2, 2011
    bismarck, nd
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    bad brake chamber. pinch off the service brake lines one at a time you should find one that starts applying the brake when you kink the hose. at the same time your also hear the air leak stop. that will be your bad brake can.
     
    KittyKicker Thanks this.
  5. KittyKicker

    KittyKicker Light Load Member

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    Dec 27, 2015
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    Thank you I will give that a try!
     
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