Brakes??????

Discussion in 'Peterbilt Forum' started by Cobbh84, Oct 20, 2021.

  1. Cobbh84

    Cobbh84 Bobtail Member

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    Oct 20, 2021
    South Carolina
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    Got a 01 peterbilt 387 with steer axle issues. When brakes are applied the truck pulls hard to the left (driver side stopping harder). I have replaced the quick release valve, abs modules, brake chambers, slack adjusters, drums, shoes. There is no wheel seal leakage and both sides are getting air because the right side is still wearing on the shoes just not as much. I am at a lose and have no clue what else could possibly be going on. Tia for any help!
     
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  3. lester

    lester Road Train Member

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    Is your push rod length correct? Or at least the same side to side?
     
    Magoo1968 Thanks this.
  4. lester

    lester Road Train Member

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    Pins and bushings good? Suppose you could put a air pressure gauge on both sides and check application pressure
     
  5. Cobbh84

    Cobbh84 Bobtail Member

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    Oct 20, 2021
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    I havent checked application pressure yet how would u recommend doing that? I would assume remove air line off the brake chamber and put a pressure gage in place of the chamber? And also everything is identical side to side with all new matching parts and problem goes away when air pressure is taken away from steer axle. If i stand on the brakes full pressure both brake chamber mounting brackets have the same i guess you would say deflection (the bracket bending a small amount from the pressure the brake chamber is applying) and they have the same throw and reaction time.
     
  6. lester

    lester Road Train Member

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    Hopefully someone with more experience than me can chime in. But it should like you've covered everything I could think of.

    To check application pressure yeah just take hose off chamber and adapt it to a pressure gauge. I'd do both at the same time and watch them both closely. I've never done that but seems like a good idea
     
  7. Cobbh84

    Cobbh84 Bobtail Member

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    Oct 20, 2021
    South Carolina
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    Ok i checked the pressures at the brake chamber and they match with the gage in the dash when the brakes are applied. I am putting a foot valve in it tomorrow (only 60$ so figured why not). After that the only thing in the whole system left will be the s cams. Which that got me thinking is it possible the scams could have a slight different pitch causing almost a gear type effect to change application pressure?
     
  8. Cobbh84

    Cobbh84 Bobtail Member

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    Oct 20, 2021
    South Carolina
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    For anybody interested it turned out to be the foot valve causing the issue thanks for the help lester
     
    Grumppy and Snailexpress Thank this.
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