Brake lag?

Discussion in 'Ask An Owner Operator' started by TheLoadOut, Mar 7, 2021.

  1. TheLoadOut

    TheLoadOut Heavy Load Member

    713
    2,474
    Nov 6, 2019
    0
    Anybody ever noticed a bit of a brake lag on their first push down on the peddle, but the 2nd push seems to have a better reaction by the brakes?
     
    Trucker61016 and 77fib77 Thank this.
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  3. 77fib77

    77fib77 Road Train Member

    4,856
    17,293
    Jul 7, 2010
    St Louis
    0
    Yep.
     
    Trucker61016 and TheLoadOut Thank this.
  4. Ridgeline

    Ridgeline Road Train Member

    16,921
    71,023
    Dec 18, 2011
    Michigan
    0
    That’s the nature of air brakes, one reason why you take a test not to have any restrictions on your license.
     
    Trucker61016 Thanks this.
  5. Happily Retired

    Happily Retired Road Train Member

    8,646
    16,586
    Apr 16, 2014
    high plains colorado
    0
    Juice brakes, yes, air brakes, should be no lag, none that I ever encountered. Again, moisture somewhere could do that.
     
  6. InTooDeep

    InTooDeep Donner party survivor

    2,070
    9,505
    Jan 17, 2016
    Carmichael CA
    0
  7. Brettj3876

    Brettj3876 Road Train Member

    6,848
    26,399
    Nov 18, 2014
    Canceling cancel culture/CCC
    0
    I've always noticed just a tiny tiny bit of lag to when the trailer grabs.
     
    77fib77, Trucker61016 and TheLoadOut Thank this.
  8. Don379

    Don379 Light Load Member

    279
    419
    Jan 7, 2021
    0
    nope, not normal. should react the same at the first push. That sounds like 100 percent foot valve issue. Put a new one in
     
    Trucker61016 and TheLoadOut Thank this.
  9. AModelCat

    AModelCat Road Train Member

    20,700
    93,091
    Jul 7, 2015
    Canuckistan
    0
    Air brakes have about 0.3-ish seconds of lag time. Takes time for the air to flow from the pedal to the relay valves and from the relay valve to the chambers. Then the chamber needs to stroke and either actuate the caliper or push on the slack adjuster and rotate the cam to push the shoes into the drum.
     
  10. SmallPackage

    SmallPackage Road Train Member

    2,352
    6,454
    Dec 20, 2019
    Marion Texas
    0
    Also depends on the type of valves and the crack pressures they have. A R12 relay valve has a hair more lag then an R14. Some may have a 1 psi crack some have a 3 psi. Also some antilock systems valves are “lazier” then others.
     
    Snailexpress and TheLoadOut Thank this.
  11. TheLoadOut

    TheLoadOut Heavy Load Member

    713
    2,474
    Nov 6, 2019
    0
    Thanks, I think I'll do that.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

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

  • Draft saved Draft deleted