Checking the Suspension Height
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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 forwardmost 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)
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- If the measurement is not within the acceptable range,
refer to the Cascadia™ 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
Table 4, Suspension Ride-Height Measurement, Dual-Leaf Spring, 23k High Ride
Measure Point
Suspension Height Measurement
Min
Target
Max
A = Measure Here
2-3/4 inch (70 mm)
3 inch (76 mm)
3-1/4 inch (83 mm)
Table 4, Suspension Ride-Height Measurement, Dual-Leaf Spring, 23k High Ride
Table 5, Suspension Ride-Height Measurement, Dual-Leaf Spring, 46k High Ride
Measure Point
Suspension Height Measurement
Min
Target
Max
A = Measure Here
2-3/4 inch (70 mm)
3 inch (76 mm)
3-1/4 inch (83 mm)
Table 5, Suspension Ride-Height Measurement, Dual-Leaf Spring, 46k High Ride
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:
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.
Important: Suspensions with Dual-Leaf Springs: Measure between the top of the U-bolt and the bottom of the axle stop.
Suspensions with Single-Leaf Springs: Measure between the top of the U-bolt pad and the bottom of the axle stop.