Freightliner Cascadia. Instruction - page 15
MOP Number
Lubrication of Front Suspensions with Grease Fittings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32–03
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32–00
Suspension Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32–01
Suspension U-Bolt Torque Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32–02
Suspension
32
Index, Alphabetical
32–00 Safety Precautions
Safety Precautions in this section apply to all
procedures within this group.
DANGER
When working on the vehicle, shut down the en-
gine, set the parking brake, and chock the tires.
Before working under the vehicle, always place
jack stands under the frame rails to ensure the
vehicle can not drop. Failure to follow these steps
could result in serious personal injury or death.
32–01 Suspension Inspection
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
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 assem-
bly could cause an accident resulting in property
damage, serious personal injury, or death.
Front Suspension Check
Inspect the front spring assemblies for cracked, bro-
ken, or abnormally bent leaves. If any of these condi-
tions exist, replace the spring assembly; see Group
32 of the Cascadia
™
Workshop Manual.
Front and Rear Suspension
Shock Absorber Check
Make sure the shock absorber brackets are tight,
and the shock absorber is not striking or rubbing the
frame or some other part of the chassis. Striking or
rubbing the frame is characterized by chafe marks on
the shock absorber body and the frame rail; see
. Check the rubber mounting bushings for
cracks, cuts, swelling, dry rot, or missing pieces. If
the shock absorber bushings are no longer service-
able, replace the shock absorber with a new one.
Inspect the shock absorber for oil leakage. Some
misting of the oil is normal, and does not mean the
shock is leaking. If the shock absorber is damaged
or leaking, replace it with a new one; see Group
32of the Cascadia
™
Workshop Manual.
Freightliner AirLiner Rear
Suspension Check
Components Checking
Inspect the forward spring brackets for wear, cracks,
and other damage. If any of these conditions exist,
replace the damaged bracket(s); see Group 32 of
the Cascadia
™
Workshop Manual.
Inspect the spring bushings for wear or other dam-
age. If any of these conditions exist, replace the
damaged bushings.
WARNING
Replace worn, cracked, or damaged spring
brackets. Failure to do so could result in bracket
breakage, possibly leading to loss of vehicle con-
trol 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 Cascadia
™
Workshop Manual.
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
f321090
05/24/2007
Fig. 1, Direct-Acting Shock Absorber (front suspension
shown)
Suspension
32
32/1
not leak. If any of these conditions exist, replace the
damaged parts; see Group 32 of the Cascadia
™
Workshop Manual.
Suspension Height Checking
IMPORTANT: Before checking the AirLiner sus-
pension 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 fol-
lowing:
• 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.
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 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. Have
an assistant chock the tires on one axle only.
2.
Mark the location of the front and rear tires on
the floor.
NOTE: The stud bolt that fastens the valve’s
height-control lever to the vertical linkage is ori-
ented correctly when the linkage rod is vertical,
as viewed from the side of the vehicle; see
. The rod may be on the forward or aft side of
the lever to get it to be vertical.
3.
Measure the distance between the left forward-
most axle stop and the suspension as indicated;
see
,
,
,
, and
for an acceptable range of heights for
each suspension.
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: Mea-
sure between the top of the U-bolt pad and the
bottom of the axle stop.
4.
If the measurement is not within the acceptable
range, refer to the Cascadia
™
Workshop Manual
01/12/2000
f320562a
1
2
3
4
5
1.
Valve Mounting Bracket
2.
Height-Control Valve
3.
Stud Bolt
4.
Linkage Rod
5.
Axle
Fig. 2, Barksdale Height-Control Valve Installation (side
view) (typical)
Suspension
32
32/2
for adjustment instructions. If the distance is
within the acceptable range, apply the parking
brakes.
32–02 Suspension U-Bolt
Torque Check
CAUTION
Failure to retorque the U-bolt nuts could result in
spring breakage and abnormal tire wear.
A
f320838b
12/20/2005
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, 20k/40k High Ride
1.
Park the vehicle on a level surface and apply the
parking brakes. Chock the tires.
2.
Check the U-bolt torque. See
for U-bolt
torque specifications. Tighten in a diagonal pat-
tern as shown in
. Set a click-type torque
wrench to the mid-point torque value for the fas-
tener being checked. Turn the wrench in a clock-
wise motion (looking up) until the torque wrench
clicks, then release pressure on the torque
wrench, and turn the wrench again until it clicks.
If the nut turns on the second application, the
bolt is stretching and must be replaced. See
Group 32 of the Cascadia
™
Workshop Manual
for bolt replacement procedures.
f320961a
A
09/24/2009
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, 20k/40k, High Ride
Suspension
32
32/3
