2009 VNL670 CAB air spring height measurement?

Discussion in 'Volvo Forum' started by tmakt, Sep 14, 2019.

  1. tmakt

    tmakt Bobtail Member

    Aug 9, 2010
    I cannot find anything on how to measure the cab height of the truck?

    I got the Hendrickson template for the steer axle. And I found the formula to calculate the drive axle but cannot find the cab height information.

    My cab still sits slightly crooked even after installing new front cab bushings, rear cab shocks, and the rod with bushings on both ends. Can the air springs be bad? I've been told that both the cab air bags are on the same air line so they should be equal. The air bags dont leak but I've never replaced them and Ive had the truck for about 500k and it is about to hit 1m. If I measure from the left frame rail to the bottom of the cab I get 8.5". The right frame rail to bottom of cab reads 8.75".

    I know this isnt a good measurement but you can see the plastic running along the bottom of the cab on the left side is slightly lower in reference to the full fairings on the side of the truck than the right side.
    stillwurkin Thanks this.
  2. stillwurkin

    stillwurkin Road Train Member

    Dec 2, 2017
    Check up under where the bags, or air springs push and mount to hold the cab up. There may be a crack or a support weakend due to corrosion or structure fatigue.
    tmakt Thanks this.
  3. KB3MMX

    KB3MMX Road Train Member

    Dec 29, 2014
    Orrstown, PA
    You can actually adjust the front brackets that hold the cab bushings somewhat.... From the slop before tightening the bolts...
  4. Johny41

    Johny41 Road Train Member

    Feb 10, 2011
    Ontario, Canada
    Any rubber parts are losing elasticity in time , they are made out of thin rubber enforced with some yarn , after awhile are losing capacity to lift and hold cab weight even if are not leaking air, just bulge expand horizontally like a used condom. I would replace them, could diminish your problem but won't fix poorly designed flimsy cab suspension.
    tmakt Thanks this.
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