freightliner M2 Plus Maintenance Manual page 117

Brakes
2.1 Remove the top cover from the governor.
2.2 Loosen the adjusting screw locknut.
2.3 To raise the pressure setting, turn the
adjusting screw counterclockwise; to
lower the setting, turn the screw
clockwise. Be careful not to overadjust.
Each 1/4 turn of the adjusting screw
raises or lowers the pressure setting
approximately 4 psi (28 kPa).
2.4 When proper adjustment is obtained,
tighten the adjusting screw locknut, and
install the top cover. The pressure range
between cut-in and cut-out is not
adjustable.
Cut-In Position
Apply soap solution around the cover and to the
exhaust port. Slight bubble leakage is permitted.
Excessive leakage indicates a faulty inlet valve or
faulty lower piston O-ring.
Cut-Out Position
Apply soap solution around the cover and to the
exhaust port. Slight bubble leakage is permitted.
Excessive leakage indicates a faulty exhaust valve
seat, exhaust stem O-ring, or O-ring at the top of the
piston.
If the governor does not function as described, or if
leakage is excessive, it is recommended that it be
replaced with a new or remanufactured unit, or
repaired with genuine Bendix parts.
42–04 Bosch Hydraulic Brake
System Inspection
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
disease. 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.
Business Class M2 Plus Maintenance Manual, 02/10/2023
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, as follows.
1.1 Apply the parking brakes. Chock the tires
to prevent vehicle movement.
1.2 Remove one or more of the lining
inspection plugs, and measure brake
lining thickness.
1.3 On front and rear axles, replace linings
worn to less than 1/16 inch (1.6 mm).
1.4 Make sure that the brake rotor and linings
are free of oil and grease.
1.5 Install the inspection plug(s).
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 1/16
inch (1.6 mm) at the thinnest point. Check the
brake pads for wear and replace, as necessary.
42–05 Dana Spicer, Haldex,
and Gunite Slack
Adjuster Lubrication
IMPORTANT: Perform a brake inspection before
lubricating the camshaft bracket.
Automatic slack adjusters that have a grease fitting
must be lubricated periodically to ensure proper
brake operation.
WARNING
Failure to lubricate slack adjusters could lead to
dragging brakes or a brake failure, resulting in
property damage, personal injury, or death.
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