Freightliner AirLiner Suspension
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 Group 32 of the 122SD and Coronado 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 Group 32 of the 122SD and Coronado Workshop Manual for instructions.
Visually check the air spring piston for cracks, chips, and broken areas. Check the air bag for rips, tears, and holes. Verify that the air spring assembly does not leak. If any of these conditions exist, replace the damaged parts. See Group 32 of the 122SD and Coronado 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:
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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.
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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.
- 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.
- Mark the location of the front and rear tires on the floor, and chock the tires on one axle only.
- Check that the height-control valve vertical linkage is connected and oriented correctly.
- Measure the distance from the axle stop to the top of the
axle U-bolt pad. The correct distance is determined by the axle and
suspension configurations; refer to Group 32 of the 122SD and Coronado Workshop Manual for details.
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Valve Mounting Bracket
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Height-Control Valve
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Stud Bolt
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Linkage Rod
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Axle
Fig. 1, Typical Barksdale Height-Control Valve Installation (side view)
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- If the axle stop measurement is not correct, see Group 32 of the 122SD and Coronado Workshop Manual for adjustment procedures.
- Apply the parking brakes, and remove the chocks.
Note: The stud bolt that fastens the height-control valve horizontal lever to the vertical linkage is oriented correctly when the linkage rod is vertical, as viewed from the side of the vehicle; see Fig.. The rod may be on the forward or aft side of the lever to get it to be vertical.