Air pressure issues 97 Pete

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Pete357, Jun 21, 2022.

  1. Pete357

    Pete357 Bobtail Member

    5
    1
    Jun 5, 2022
    0
    Hello, I have a 97 Pete 357 Dump Truck and my issue is my air dryer purges continuously but my air pressure gauge reads 105 on both needles. I have put two compressors on it with two new governors, two air dryers and replaced the main line from compressor to the dryer. One thing that I did notice was when I changed the air line, my pressure did not drop fast and the dryer started going off quicker. The line did leak pretty good. I have pressure in all the tanks and not a lot of water. My mechanic did put the governor on and saw the gauge was reading low. He did adjust the governor up and the gauge went to 120. The dryer went off all the time when driving and every 10 seconds at idle. I did replace the warning sensors and the ones I took out did not look that old. The gauge has one air line and two wires. People I have talked to said change the dryer again and the purge valve. The person I got the truck from told me he change the dryer not to long before I bought it. I thought of replacing the gauge but I do not want to keep changing parts and having the same issues. Any assistance or advice is appreciated.
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  3. lwlevens

    lwlevens Medium Load Member

    619
    424
    Feb 9, 2018
    0
    How about changing the air dryer filter. Mine was popping off every 20 seconds or so until I changed the filter.
     
    Last edited: Jun 21, 2022
  4. Big Road Skateboard

    Big Road Skateboard Road Train Member

    1,880
    8,043
    May 2, 2021
    0
    On that 97, you likely still have stratoflex #4 air lines to the governor. I would expect a leak in the sense line from air tank to govenor. Those stratoflex lines get porus over the years.

    Spray those lines with soapy water and i spect you'll find the issue.

    The only reason it's purging is beacuse the governor is telling it to. No sensors or gauges affect it.
     
    Hammer166, lester and AModelCat Thank this.
  5. AModelCat

    AModelCat Road Train Member

    24,768
    124,815
    Jul 7, 2015
    Canuckistan
    0
    I'd get a mechanical air pressure gauge and stick it on the wet tank. See what's going on there.

    Typically the governor will get its signal from the wet tank. Air in primary and secondary reservoirs is protected by one-way check valves, so any loss of pressure in the wet tank will not be seen on the dash gauges.
     
    Pete357 Thanks this.
  6. lester

    lester Road Train Member

    2,203
    5,378
    Jan 2, 2012
    NW, Iowa
    0
    Yes my first thought to is that the signal has a leak. But..hmm...the signal line tells the compressor when to start building pressure again. So yeah if that line leaks it tells the compressor to build pressure again and then since you haven't really lost actual pressure the dryer will purge again and is starts all over. Change the signal line... had to talk myself through that, sorry
     
    Pete357 and Hammer166 Thank this.
  7. Big Road Skateboard

    Big Road Skateboard Road Train Member

    1,880
    8,043
    May 2, 2021
    0
    BTW, if your mechanic can't fix a simple issue like this, may need to look for another.
     
  8. kranky1

    kranky1 Road Train Member

    1,874
    6,897
    Sep 16, 2015
    Ontario, Canada
    0
    Not a mechanic. That’s probably a technician, looking for where the computer that tells him what’s wrong with it plugs in.
     
    Big Road Skateboard Thanks this.
  9. Pete357

    Pete357 Bobtail Member

    5
    1
    Jun 5, 2022
    0
    When I changed the dryer I put a new filter on both times and the same thing is happening
     
    lwlevens Thanks this.
  10. Pete357

    Pete357 Bobtail Member

    5
    1
    Jun 5, 2022
    0
    I will definitely check this and update the results
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  • Draft saved Draft deleted