Western Star 47X 2020, Maintenance Manual

Page: 124 / 166

7. Install the cover tetraseal.
8. Install the reservoir on the cover and tighten the
capscrews.
9. Fill the reservoir with 40 ounces (1183 mL) of
methyl alcohol, then install the filler cap.
42–05 Brake Inspection
Parking Brake Operational Check
IMPORTANT: This procedure should be per-
formed prior to lubrication of the brake compo-
nents.
CAUTION
Perform the following check in a clear safe area. If
the parking brakes fail to hold the vehicle, per-
sonal injury or property damage may result.
1. With the engine running, and air pressure at cut-
out pressure, set the parking brake.
2. Put the vehicle in the lowest gear and gently at-
tempt to move it forward. The vehicle should not
move. If the vehicle moves, the parking brakes
are not operating correctly and must be repaired
before the vehicle is returned to service. See
Group 42 of the 47X and 49X Workshop Manual
for repair procedures.
Brake Component Inspection
Air Disc Brakes
1. Park the vehicle on a level surface, shut down
the engine, and set the parking brake. Chock the
tires. Once the tires are chocked, release the
parking brake.
2. Grip the caliper/carrier assembly by the chamber
and verify that it slides in and out freely. Free
play movement is 0.024 to 0.043 in (0.6 to 1.1
mm).
IMPORTANT: The following step to inspect the
caliper mounting bolts should only be performed
at the initial maintenance (IM) interval.
3. Check the caliper mounting bolts by hand to see
if they are loose.
Use a torque wrench set to the applicable torque
value and the Meritor extension tool 3256B1354
to check the caliper mounting bolts. The Meritor
extension tool will only work on M20 axial
mounted bolts; radial calipers use a unique hex-
head bolt. See
Table 1 and Table 2 .
If the caliper mounting bolts turn at all, take the
vehicle to an authorized Western Star dealer for
repair.
If the bolts do not turn, no further work is
needed.
Caliper Mounting Bolt Torque Values
Caliper Description
Torque:
lbf·ft (N·m)
Bendix, Axial Mounted 375±25 (508±34)
Bendix, Radial Mounted 225±22.5 (305±31)
Meritor, Axial Mounted
400±50 (542±68)
Meritor, Radial Mounted
Wabco Maxxus, Radial Mounted 295±22 (400±30)
Table 1, Caliper Mounting Bolt Torque Values
Brakes
42
47X and 49X Maintenance Manual, August 2020
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