Air Suspension not airing up all the way

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by mechman, Dec 2, 2021.

  1. mechman

    mechman Bobtail Member

    3
    2
    Dec 2, 2021
    0
    I have a 2001 Volvo that rises to ride height just fine with an unloaded trailer. As soon as I load it I'm riding on my fenders. I drained any water out of the tanks and replaced the air dryer unit while it was in the shop as well as the air levelling valve. Nothing seems to work. I removed the dump signal air line to the levelling valve and there is no air coming to it so the dump valve isn't the issue. Even with the tires riding on the fenders the air bags are still hard but just not enough pressure to lift with load. Is there a priority valve or something I'm missing that would cause the levelling valve to not receive full tank pressure? Thanks
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  3. Goodysnap

    Goodysnap Road Train Member

    2,891
    6,714
    Jul 12, 2017
    0
    Install a pressure gauge at your supply line at the leveling valve. You will likely find low pressure. Trace it back to the air tank where you will likely find a pressure regulator in the tank which is likely blocked or not delivering enough pressure. Newer trucks can be regulated or plumbed directly thru the air dryer.
     
    Oxbow, mechman and Rideandrepair Thank this.
  4. mechman

    mechman Bobtail Member

    3
    2
    Dec 2, 2021
    0
    Thanks! I plumbed it direct and it still did it. Ended up being 3 air bags that were rusted through on top with pin holes that weren't making noise.
     
    Oxbow and Goodysnap Thank this.
  5. goga

    goga Medium Load Member

    689
    1,188
    Nov 11, 2021
    Earth..
    0
    Replace the leveling valve as well, since you are doing air bags. Hope all 4 are getting replaced?)
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  • Draft saved Draft deleted