Suspension of the Freightliner AirLiner

cen mm 32.01.000

Warning: Do not replace individual leaves of a damaged leaf spring assembly; replace the complete spring assembly. Visible damage (cracks or breaks) to one leaf causes hidden damage to other leaves. Replacement of only the visibly damaged part(s) is no assurance that the spring is safe. On front spring assemblies, if cracks or breaks exist in the two top leaves, a loss of vehicle control could occur. Failure to replace a damaged spring assembly could cause an accident resulting in property damage, serious personal injury, or death.

Inspect the forward and rear spring brackets for wear, cracks, and other damage. If any of these conditions exist, replace the damaged bracket(s). See of the Century Class Trucks Workshop Manual for instructions.

Warning: Replace worn, cracked, or damaged spring brackets. Failure to do so could result in bracket breakage, possibly leading to loss of vehicle control and resulting in personal injury or property damage.

Inspect the crossmember(s) and gussets for wear, cracks, and other damage. If any of these conditions exist, replace the damaged parts. See of the Century Class Trucks Workshop Manual for instructions.

Important: Before checking the AirLiner suspension height, make sure there is no load on the chassis, and the trailer is unhitched.

Important: To prevent voiding the warranty on Barksdale height-control valves, note the following:

  • Do not overtighten the bolts in the Barksdale height-control valve housing. The bolts should not be loose, and should not require tightening. Only if necessary, tighten the valve housing bolts 45 lbf·in (500 N·cm). Any damage to the valve housing will void the warranty.

  • Do not attempt to disassemble the Barksdale valve body or the control lever. There are no serviceable parts in the valve, and any disassembly will void the warranty.

Notice: When removing or loosening a Barksdale height-control valve from a mounting bracket, always hold the valve-side mounting studs in place with an Allen wrench while loosening or tightening the nuts that attach the valve to the bracket. Because the mounting studs are threaded into the valve body, loosening the nuts without holding the studs can tighten the studs, which can crush the valve body and damage the valve. Conversely, tightening the nuts without holding the studs can back the studs out, causing a separation of the two halves of the valve body, and possibly a leak.

  1. Park the vehicle on a level surface, using a light application of the brakes. Do not apply the parking brakes. Shift the transmission into neutral, and build the secondary air pressure to at least 100 psi (690 kPa). Shut down the engine.
  2. Mark the location of the front and rear tires on the floor, and chock the tires on one axle only.
  3. Check the length of the overtravel lever between its pivot points. See Fig., Ref. A.

    • Measure the length of the overtravel lever between these two points.

    1. V-Shaped Mark

    2. Adjustment Locknut

    3. Overtravel Lever

    4. Cotter Pin

    5. Linkage Rod

    Fig. 1, AirLiner Overtravel Lever and Linkage Rod Measurement

    1. If the vehicle is equipped with an adjustable leveling valve, the length should be 8 inches (203 mm). If the length is incorrect, see of the Century Class Trucks Workshop Manual for adjustment procedures.
    2. If the vehicle is equipped with a fixed leveling valve, see of the Century Class Trucks Workshop Manual for the overtravel lever length for the rear axle installed in your vehicle.
  4. On single-drive rear axle configurations, measure the distance from the bottom of the left axle stop to the top of the U-bolt pad. On tandem (dual-drive) rear axle configurations, measure the distance from the bottom of the forwardmost left axle stop to the top of the axle U-bolt pad. See Fig., Ref. A. The correct distance for single and dual-drive rear axles is between 2-3/8 inches and 2-7/8 inches (60 to 73 mm).

    • Measure height here.

    1. Left Forwardmost Axle Stop

    Fig. 2, AirLiner Axle Stop Measurement

  5. If the axle stop measurement is not correct, see of the Century Class Trucks Workshop Manual for adjustment procedures.
  6. Apply the parking brakes, and remove the chocks.
Note:
Parent topic: Suspension of the Rear Check
Document Number: 0000122034
Manual Publication Date: 2025-02-11
Topic Publication Date: 2024-06-04