freightliner Custom Classic MT45 2022 Maintenance Manual page 92

42
42–02 Brake Lines Check,
Hydraulic Disc Brakes
Check all hydraulic lines and fittings for damage,
leakage, or looseness.
Replace damaged or leaking components, and
tighten loose fittings.
42–03 Brake Lining Wear
Check, Hydraulic Disc
Brakes
Before checking lining wear with the wheel removed,
review the following brake lining exposure warnings.
WARNING
Breathing brake lining dust (asbestos or non-
asbestos) could cause lung cancer or lung dis-
ease. Unless exposure can be reduced below legal
limits, wear an air purifying respirator approved
by MSHA or NIOSH at all times when servicing the
brakes, starting with removal of the wheels and
continuing through assembly.
To minimize the possibility of creating airborne brake
lining dust, clean the dust from the brake rotor, brake
caliper, and brake assembly, using an industrial-type
vacuum cleaner equipped with a high-efficiency filter
system. Then, using a rag soaked in water and
wrung until nearly dry, remove any remaining dust.
Do not use compressed air or dry brushing to clean
the brake assembly.
1. Check lining wear.
1.1 Apply the parking brake and chock the
tires to prevent vehicle movement.
1.2 On front and rear axles, replace linings
worn to less than 3/16 inch (4.8 mm).
1.3 Make sure that the brake rotor and linings
are free of oil and grease.
2. If the wheel and hub assembly is removed from
the axle, check lining wear. Replace the linings
on all brake assemblies if worn to less than 3/16
inch (4.8 mm) at the thinnest point.
NOTE: To replace the brake linings, see the ap-
plicable foundation brake section in Group 42 of
42/2
the Walk-In Van Chassis Workshop Manual, or
take the vehicle to an authorized Freightliner
dealer.
42–04 Brake Caliper Slide Pin
Lubrication, Bosch
Brakes
NOTE: There is no set maintenance interval for
lubricating pin-slide hydraulic disc brake cali-
pers.
Apply 1/8 oz (3.5 g) Aeroshell grade 5 grease to
each of the two guide pin and guide pin bore sets.
See the Bosch Pin Slide Disc Brakes Service Manual
for additional information.
IMPORTANT: The later ZOH-T caliper has im-
portant differences from the early ZOPS caliper.
ZOPS calipers (since 1998) and ZOH-T calipers
(since 2002) use different slide pins and bolts.
See Fig. 2 and Fig. 3. The later trailing pin is
identified by notches and has a rubber bushing.
Flange-head instead of hex-head bolts are used
with the later caliper. The later bolts have a fine
thread rather than a coarse thread pitch, are
longer, differently colored, and are tightened to a
higher torque specification. Use only the ZOH-T
bolts to assemble a ZOH-T caliper. The ZOPS
caliper bolts have a different thread pitch and
will not assemble correctly in a ZOH-T caliper
mounting. Also, the ZOH-T bolts will not as-
semble correctly in a ZOPS caliper. Do not in-
terchange parts. It is permissible to use both
ZOH-T pins and ZOH-T bolts in a ZOPS anchor
plate, but they must be replaced as sets. Both
the pins and the bolts must be changed.
DANGER
The correct pins, bolts, and bolt torque must be
used. If not, brake function could be impaired and
lead to loss of control of the vehicle, which could
result in personal injury, death, or property dam-
age.
IMPORTANT: The ZOH-T caliper assembly is
similar in appearance to the existing ZOPS cali-
per. The only obvious difference is that one of
Walk-In Van Chassis Maintenance Manual, October 2019
Brakes