26
BRAKE ACTUATOR AND SPRING BRAKE
REPLACEMENT
CAUTION: Replace actuator and spring brakes only
with the same as originally installed on the vehicle.
Replacement with alternate equipment (without written
authorization from Bendix and the vehicle manufacturer)
could compromise brake performance.
CAUTION: Follow all standard safety procedures
including, but not limited to, those on page 2 of this
service manual. See the vehicle manufacturer's
recommendations. When working on foundation
brakes, be sure that the vehicle is on level ground,
that the vehicle is parked by other means than the
foundation brakes, and that the wheels are chocked.
Brake Chamber Removal
With all air pressure drained from the air brake system,
disconnect the air hose from the brake chamber (18/2).
Remove and discard brake chamber mounting nuts (see
Figure 50, arrows B).
Brake Chamber Installation
Note: New brake chambers (18/2) have drain plugs
installed (see Figure 50, arrows A). After installation,
remove whichever plug is at the lowest position. Be sure
that all other drain holes remain plugged. The drain hole
must be aligned downwards (or within ±30°) when installed
on the vehicle.
Before installing the new brake chamber, the actuator
flange (see Figure 51, arrow C) must be cleaned, and
inspected. Consult the vehicle manual. The spherical
cup in the lever (19) must be greased with white grease
(Part No. II14525 or II32868).
CAUTION: Do not use grease containing molybdenum
disulfate.
See Figure 52. The seal, as well as the pushrod area must
be clean and dry.
CAUTION: Do not use brake chambers with seals with a
thickness less than 0.12 in. (3 mm). Use only actuators
which are recommended by the vehicle manufacturer.
Install the brake chamber using new self-locking nuts (EN
ISO 10513). Tighten alternately both the nuts step by step
up to a final torque of 133 ± 7 ft. lbs (180 ± 10 Nm).
Re-connect the air hose and be sure that the hose is not
twisted or in contact with moving vehicle components. The
air hose routing must allow for full caliper travel. Test for
leakage and check the brake operation and effectiveness
before returning vehicle to service.
19
B
18/2
Brake
Chamber
or
18/1
Spring
Brake
A
B
C
FIGURE 50 - ACTUATOR INSTALLATION
FIGURE 51 - ACTUATOR FLANGE
Seal
Pushrod area
0.12 in. (3 mm)
FIGURE 52 - CAP INSTALLATION