Peterbilt ABS and dash valve leaking.

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by jriol94, Dec 15, 2021.

  1. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    Have both valves leaking when I release tractor brakes. When I push on the brake pedal it stops. I’ve loosened up all the service lines on the brake chambers, they’re not pushing any air into the service line. I then changed abs valve, nothing. Now changed dash valve and again, nothing. What else can I look at?

    trucks a 2002 379
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  3. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    Sorry guys don’t know why it posted twice. Trying to figure out how to remove one
     
  4. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    Sorry guys. Posted twice trying to figure out how to remove one
     
  5. Goodysnap

    Goodysnap Road Train Member

    2,990
    6,989
    Jul 12, 2017
    0
    Please tell us what valve is leaking air and where exactly is the air leaking from?

    This air leaks only when the yellow knob is in, but stops leaking when depressing the brake pedal.

    Just want to be clear- When did it start? suddenly? after a repair?
     
  6. jriol94

    jriol94 Bobtail Member

    17
    7
    Nov 14, 2020
    0
    ABS valve under fifth wheel between tandems and dash valves. Both leak as soon as I push yellow in. Press the brake pedal and it stops while pressed in.
    Started suddenly
     

    Attached Files:

    BoxCarKidd Thanks this.
  7. tigerkilla

    tigerkilla Bobtail Member

    8
    1
    Jul 9, 2014
    Philadelphia. Pa.
    0
    I got an 05’ 379… having the same issues as you except when I depress brake pedal air spills out exhaust on dash valve. So far have replaced abs valve,tractor protection valve,and 1 brake chamber…. I’m kinda at a loss.. commenting to follow.
     
  8. BoxCarKidd

    BoxCarKidd Road Train Member

    3,868
    5,505
    Aug 26, 2014
    0
    ABS valve is from vent on bottom? Dash valves leak air from where?
     
  9. BoxCarKidd

    BoxCarKidd Road Train Member

    3,868
    5,505
    Aug 26, 2014
    0
    Really wondering if air is leaking from the dash valves or if you just hear air flow through them.
    I would start with crimping off or disconnecting drive axle service hoses one at a time. That is while leaking looking for a bad chamber.
     
  10. tigerkilla

    tigerkilla Bobtail Member

    8
    1
    Jul 9, 2014
    Philadelphia. Pa.
    0
    Abs spillage from bottom vent dash spillage from exhaust port
     
    BoxCarKidd Thanks this.
  11. BoxCarKidd

    BoxCarKidd Road Train Member

    3,868
    5,505
    Aug 26, 2014
    0
    I am stumped. Would like to know what you find.
    Is there another like a QR1 C ? connected in the system anywhere? I would look for something like that being bad. Maybe a two way check valve.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  • Draft saved Draft deleted