freightliner 108SD 2021, Driver Manual

Page: 81 / 191

NOTICE
To prevent voiding the warranty on Barksdale
height-control valves, observe the following:
•
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 with-
out holding the studs can back the studs out,
causing a separation of the two halves of the
valve body, and possibly a leak.
•
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 disas-
sembly will void the warranty.
1. Park the vehicle on a level surface, using a light
application of the brakes. Do not apply the park-
ing 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 that the height-control valve vertical link-
age is connected and oriented correctly.
NOTE: The stud bolt that fastens the height-
control valve horizontal lever to the vertical link-
age is oriented correctly when the linkage rod is
vertical, as viewed from the side of the vehicle;
see
Fig. 4 . The rod may be on the forward or
aft side of the lever to get it to be vertical.
4. 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 con-
figurations; refer to
Group 32 of the 108SD and
114SD Workshop Manual for details.
5. If the axle stop measurement is not correct, see
Group 32 of the 108SD and 114SD Workshop
Manual for adjustment procedures.
6. Apply the parking brakes, and remove the
chocks.
Freightliner TufTrac
1. Inspect the suspension spring assemblies for
pitted, cracked, broken, or abnormally bent
leaves, and extreme rust. If any of these condi-
tions exist, replace the spring assembly.
WARNING
Do not replace individual leaves of a damaged leaf
spring assembly; replace the complete spring as-
sembly. Visible damage (cracks or breaks) to one
leaf causes hidden damage to other leaves. Re-
placement of only the visibly damaged part(s) is
no assurance that the spring is safe. On front
f320562a 10/05/2016
1 2
3
4
5
1. Valve Mounting
Bracket
2. Height-Control Valve
3. Stud Bolt
4. Linkage Rod
5. Axle
Fig. 4, Typical Barksdale Height-Control Valve
Installation (side view)
Suspension
32
108SD and 114SD Maintenance Manual, September 2015
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