Out of service

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Alex K, Jan 18, 2022.

  1. Alex K

    Alex K Bobtail Member

    9
    2
    Jan 17, 2022
    0
    So i got out of service because service and emergency brake wouldn't pop out when i pumped my brake during dot inspection. They actually did but when psi hit zero. The ticket said it's tractor protection valve. When i remove red line and release the air it actually pops out. Only when i pump my foot brake it just doesn't want to pop. I've replaced tractor protection valve, dash valve, foot valve, both abs valves...all the valves, and still the same
     
    austinmike Thanks this.
  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

    1,303
    4,445
    May 2, 2021
    0
    Are your pressure gauges accurate?
     
    lwlevens and Bean Jr. Thank this.
  4. ZVar

    ZVar Road Train Member

    9,869
    20,550
    Sep 10, 2010
    Flint, MI
    0
    Instead of keep firing the parts cannon at it, take it to a mechanic that can diagnose it.
    Sometimes spending money upfront saves a ton.
     
    bzinger, Heavyd, lwlevens and 3 others Thank this.
  5. Alex K

    Alex K Bobtail Member

    9
    2
    Jan 17, 2022
    0
    I would say yes. Since i changed the air compressor, it does charge to about 140 psi, used to cut off at 125. And when i pump the break primary tenk gets empty much faster then secondary, which wasn't the case
     
  6. nikmirbre

    nikmirbre Road Train Member

    4,381
    6,822
    Jul 27, 2011
    High Point NC
    0
    About 15 years ago in Virginia I got shut down for the same thing in Virginia. Turns out I replaced the valve(red and yellow buttons) but, I failed to replace the spring behind the button......
     
    Badmon Thanks this.
  7. Mike250rs

    Mike250rs Heavy Load Member

    881
    7,061
    Sep 24, 2019
    Raleigh, NC
    0
    Does your truck have a trolly brake? Seen those leak and cause random weird issues.
     
  8. Heavyd

    Heavyd Road Train Member

    7,374
    5,674
    Feb 4, 2009
    0
    Ultimately, its the dash valves themselves and only the dash valves that will pop their buttons out when down to very low psi. If they are stuck in at zero psi, then they are sticking. If you just replaced the dash valve, then it is warranty parts failure. Get another one. A brand new dash valve set will never allow the buttons to stay pressed in with no air pressure behind them. So you can quickly test it right out of the box by pressing each button in and they should be spring loaded to pop right back out.
     
  9. Tiger001

    Tiger001 Bobtail Member

    3
    0
    Jan 21, 2022
    0
    @Heavyd I have 2012 prostar Max13. It shuts off while driving.. Will start back up after 30 mins. It was doing this 1-2 time week but recently it is shutting off few times a day.
    Thank you!
     
  10. Heavyd

    Heavyd Road Train Member

    7,374
    5,674
    Feb 4, 2009
    0
    Shutting off at random can be a few different things with different troubleshooting directions. One common problem is simple loss of ignition power to the engine only. When this happens, just the engine shuts off but everything else stays on, so you get a specific combination of warnings. You will get the ABS and trac warnings lights on, and "Electrical Fault" message in the dash. These modules will log faults that they have lost communication with the engine. Another problem is everything shutting off, so the engine will shut down along with everything else, like you shut the key off. This will not cause warning lights or codes. In both situations, running the engine and going around and wiggling all the harnesses around the engine, ecm and batteries may induce your problem so you can track it down. Always follow the basics first and check battery and main ground connections.

    But, the laptop is the first tool I grab and check for codes related to shutting down, such as fuel pressures, and trouble shoot from there.
     
    nikmirbre and Badmon Thank this.
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  • Draft saved Draft deleted