Rough ride western star 4900 FA car carrier

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Truckerguy917, Mar 2, 2026.

  1. Mar 2, 2026 #1
    Truckerguy917

    Truckerguy917 Bobtail Member

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    2013 Western star 4900 FA really rough ride. Went to the shop and checked the springs airbags shocks and u bolts. They said all look good. Loaded bobtail or empty trailer whenever I'm going over rough patches in the road truck feels like it doesn't even have air ride. Very stiff. It is a car carrier unit I checked the frame also and the headrack where they connect with eachother. Cab bags and bushings also checked.

    Very noticeable on small bumps of any kind and pot holes. Feels like its coming from the drives and cab is bouncing alot as well

    Had a trans job and motor mounts done recently rode fine for about 2 weeks until I noticed. Any ideas? Thank you
     
    Truckerguy917, Mar 2, 2026
    Truckerguy917, Mar 2, 2026
    #1
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  3. Mar 3, 2026 #2
    JB7

    JB7 Road Train Member

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    Did anyone check the suspension ride height? Manually move the valve lever and make sure air is going into the bags and exhausts air. Do the same with the cab valve. Check the adjustment on the cab valve and the linkage. The bags may be inflated to the max or not inflating at all.
     
    JB7, Mar 3, 2026
    JB7, Mar 3, 2026
    #2
  4. Mar 8, 2026 #3
    Rideandrepair

    Rideandrepair Road Train Member

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    I agree. Looks good doesn’t mean a thing. Heights need to be measured and set. Test driven, re-checked.
     
    Rideandrepair, Mar 8, 2026
    Rideandrepair, Mar 8, 2026
    #3
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