Checking the Suspension Height
Important: 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.
- 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. Have an assistant chock the tires on one axle only.
- Mark the location of the front and rear tires on the floor.
- Measure the distance between the left forward-most axle
stop and the suspension as indicated; see Table., Table., Table., Table. and Table. for an acceptable range of heights for each suspension.
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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, Barksdale Height-Control Valve Installation (side view) (typical)
Suspensions with Single-Leaf Springs: Measure between the top of the U-bolt pad and the bottom of the axle stop.
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- If the measurement is not within the acceptable range,
refer to in the Western Star
47X and 49X Workshop Manual for adjustment instructions.
If the distance is within the acceptable range, apply the parking
brakes.
Table 1, Suspension Ride-Height Measurement, Dual-Leaf Spring, 21k/40k High Ride
Measure Point Suspension Height Measurement Min Target Max A = Measure Here
2-3/8 inch (60 mm)
2-5/8 inch (67 mm)
2-7/8 inch (73 mm)
Table 1, Suspension Ride-Height Measurement, Dual-Leaf Spring, 21k/40k High Ride
Table 2, Suspension Ride-Height Measurement, Single-Leaf Spring, 21k/40k, High Ride
Measure Point Suspension Height Measurement Min Target Max A = Measure Here
2-3/8 inch (60 mm)
2-5/8 inch (67 mm)
2-7/8 inch (73 mm)
Table 2, Suspension Ride-Height Measurement, Single-Leaf Spring, 21k/40k, High Ride
Table 3, Suspension Ride-Height Measurement, Single-Leaf Spring, 40k Low and Mid Ride
Measure Point Suspension Height Measurement Min Target Max A = Measure Here
2-3/8 inch (60 mm)
2-1/2 inch (64 mm)
2-7/8 inch (73 mm)
Table 3, Suspension Ride-Height Measurement, Single-Leaf Spring, 40k Low and Mid Ride
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.
Note: The stud bolt that fastens the valve's height-control 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.
