Air pressure problem

Discussion in 'Trucks [ Eighteen Wheelers ]' started by niksafree, Mar 24, 2018.

  1. niksafree

    niksafree Bobtail Member

    11
    8
    Mar 24, 2018
    0
    Hello and good day everyone,
    Truck is running on 6.5 rpm and air pressure keeps falling, goes bellow 60, I can hear air dryer purge too often. After I increase the rpm with cruise control to 8, then it builds up the pressure and goes to 125, drops normally to 95 and then It goes back to 125. Also if I turn off the engine, after less then 30 mins pressure is way below 60.
    I would appreciate some answers.
     
    Last edited: Mar 24, 2018
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  3. sealevel

    sealevel Road Train Member

    2,664
    10,282
    May 31, 2012
    U.S. 41
    0
    You have a air leak. Cut the truck off, get out and crawl around. Its a bad one too, you will hear it.
     
    Justrucking2 Thanks this.
  4. xsetra

    xsetra Road Train Member

    5,169
    7,105
    Aug 21, 2011
    0
    Do what sealevel said.
    Charge up your air. Set brakes disconnect air to trailer. If you still lose pressure, the leak is in the tractor.
    You now know if the leak is in tractor or trailer. Crawl under and listen.
    A short hose helps narrow the search.
    One end to your ear the other end you listen for leak.
    Also soapy water spray works great.
    Good luck.
     
    HopeOverMope Thanks this.
  5. niksafree

    niksafree Bobtail Member

    11
    8
    Mar 24, 2018
    0
    Update: Pressure in tank 1, doesn't go under 60.
    Pressure in tank 2 goes to 0.
    I have already tried going under, but I can't hear anything. Will try with the soapy water.
     
  6. Smellfunny

    Smellfunny Road Train Member

    1,446
    967
    Jan 28, 2012
    South Carolina
    0
    Best thing to do is disconnect discharge line off of compressor and put shop air to it and listen for leaks like that.
     
  7. niksafree

    niksafree Bobtail Member

    11
    8
    Mar 24, 2018
    0
    Air compressor was bad. Replacing it fixed the pressure problem, but air leak is still there.
     
  8. Lav-25

    Lav-25 Medium Load Member

    570
    906
    Mar 31, 2018
    0
    Air up truck , chock tires , turn off truck, listen and trace.( do it bob tail) check bypass vavles and susp. Leveler and supply air to air bags.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

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