Sinking Sleeper

Discussion in 'Peterbilt Forum' started by Racked&Stacked, Oct 4, 2023.

  1. Racked&Stacked

    Racked&Stacked Bobtail Member

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    Oct 4, 2023
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    I have a 2020 Peterbilt 389 car hauler. It’s obvious to me the sleeper has dropped down. I’ve had a couple of mechanics test the leveling valve/ air bags and shocks who’ve all said they’re okay.
    I can tell by the rough/different way it rides, that something’s not right.
    The bags appear to be holding air but could they be dry rotted and/ or maybe I just need new shocks and bags?
    Anyone had any similar issues? IMG_7654.jpeg
     
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  3. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    Is it ever the right height? Has anybody adjusted the leveling valve?
     
  4. Racked&Stacked

    Racked&Stacked Bobtail Member

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    Oct 4, 2023
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    it’s only been maybe a couple weeks that I’ve been able to notice it sinking and has stayed this way.
    I used to have a truck that would sink down overnight but this one’s never done that.
    Had a Peterbilt mechanic look at it and say the leveling valve was fine and the bags were holding air. He didn’t say anything about adjusting the valve.
     
  5. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    I'd see if the valve has moved. If not pull the rod off and lift the valve arm and see if the bags come up.
     
  6. JB7

    JB7 Medium Load Member

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    Check and make sure that there is no contact between the top of the sleeper and the rails that the SUV is sitting on. Or that nothing is contacting the cab or sleeper. It does not look like there is enough space for the cab/sleeper to rise up and level off. If everything is all clear then check the leveling valve as Big Road Skateboard suggests.
     
  7. Transportauto

    Transportauto Light Load Member

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    Just check the height and reset, maybe the valve rod last ots position, if the bags are not leaking enough to keep the cab up and of the valve is operating normal there isn't much else other then where the bags ride beginning to bend inward, then again the leveling valve would compensate, only seen that on rust buckets where the aluminum was so corroded it became weak.
    Also being a parking lot we don't want much movement, not 1 parking lot I owned had any suspension on the cabs
     
  8. Lennythedriver

    Lennythedriver Road Train Member

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    Looks like an airbag is blown?
     
  9. NightWind

    NightWind Road Train Member

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    Mine did that it was a faulty air suspension valve
     
    Oxbow Thanks this.
  10. Judge

    Judge Road Train Member

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    579 pet done that, the plastic leveling valve broke the ball joint off, common on them, know another guys did same thing. shops don’t look, see how much air is in your cab bags, mine was just very little and cab was sitting down like that.
     
    Last edited: Jan 2, 2024
    Reason for edit: spelling
    Oxbow and JB7 Thank this.
  11. Judge

    Judge Road Train Member

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    May be different but mine is this valve, IMG_5469.png The ball joint broke, allowed it to move freely, but when it went down it’d release all cab air.
    Yours in photo is older model, but maybe give somewhere to look
     
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