All air tanks full no secondary pressure

Discussion in 'Trucks [ Eighteen Wheelers ]' started by dirthaller, May 2, 2025 at 4:00 PM.

  1. dirthaller

    dirthaller Road Train Member

    1,034
    11,804
    Sep 22, 2011
    Coloratah
    0
    2014 Peterbilt 389 discharged all the air to fix air leak (firewall manifold) and now my tanks all build air, no leaks, but no secondary air pressure. The brakes work, the trailer air works, but the secondary needle won’t budge. No transmission air, seat air etc. I’ve even pulled both primary and secondary lines off the air dryer and both are pushing air.
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Big Road Skateboard

    Big Road Skateboard Road Train Member

    5,723
    29,917
    May 2, 2021
    0
    I think Pete used check valves at the tanks on those trucks. If you've got air outta the dryer ports, what happens when you pull the tank drain?
     
    dirthaller Thanks this.
  4. dirthaller

    dirthaller Road Train Member

    1,034
    11,804
    Sep 22, 2011
    Coloratah
    0
    Full pressure all tanks. Unless the air tank is split and there is a check valve inside the tank
     
  5. dirthaller

    dirthaller Road Train Member

    1,034
    11,804
    Sep 22, 2011
    Coloratah
    0
    Is there a check valve coming out of a tank that just serves secondary?
     
  6. Big Road Skateboard

    Big Road Skateboard Road Train Member

    5,723
    29,917
    May 2, 2021
    0
    What dryer, or how many air lines are on it? Maybe a pic?
     
    dirthaller Thanks this.
  7. Big Road Skateboard

    Big Road Skateboard Road Train Member

    5,723
    29,917
    May 2, 2021
    0
    Also, did you replace the air manifold?
     
    dirthaller Thanks this.
  8. dirthaller

    dirthaller Road Train Member

    1,034
    11,804
    Sep 22, 2011
    Coloratah
    0
    I just unhooked the two that were leaking inside and outside of the cab then spliced them together with extra air line to see if there were any other leaks and there’s not. Although if I had some secondary air…….. might leak?
     
  9. dirthaller

    dirthaller Road Train Member

    1,034
    11,804
    Sep 22, 2011
    Coloratah
    0
    ADIS primary and secondary outputs are right below. The governor in the front four auxiliary ports in the back has the 10 inch purge tank
     
  10. dirthaller

    dirthaller Road Train Member

    1,034
    11,804
    Sep 22, 2011
    Coloratah
    0
     

    Attached Files:

  11. dirthaller

    dirthaller Road Train Member

    1,034
    11,804
    Sep 22, 2011
    Coloratah
    0
    I even tried teeing the two outputs of the dryer together. So primary and secondary were both charged in case it was a pressure problem off the dryer. Purge valve and governor works fine.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.