Thomas SAF-T-LINER C2, Руководство по обслуживанию

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Operational Tests
1. Start the engine, build air pressure in the air
brake system, and check the pressure registered
by a dash or test gauge at the time the governor
cuts out, stopping the compression of air by the
compressor. The cutout pressure should be in
accordance with the pressure setting of the piece
number being used. Common cutout pressures
are from 125 to 135 psi (862 to 931 kPa).
With the engine still running, make a series of
brake applications to reduce the air pressure and
observe at what pressure the governor cuts in
the compressor. As in the case of the cutout
pressure, the cut-in pressure should be in accor-
dance with the pressure setting of the piece
number being used. Cut-in pressure is 105 psi
(724 kPa).
NOTE: If the governor cover is marked nonad-
justable and the adjusting stem has been
sheared off, this is a non-serviceable governor
and must be replaced with a new or remanufac-
tured unit.
2. Never condemn or adjust the governor pressure
settings unless they are checked with an accu-
rate test gauge or a dash gauge that is register-
ing accurately. If the pressure settings of the D-2
governor are inaccurate or it is necessary that
they be changed, the adjustment procedure fol-
lows.
2.1 Remove the top cover from the governor.
2.2 Loosen the adjusting screw locknut.
2.3 To raise the pressure settings, turn the
adjusting screw counterclockwise. To
lower the pressure settings, turn the ad-
justing screw clockwise. Be careful not to
overadjust. Each 1/4 turn of the adjusting
screw raises or lowers the pressure set-
ting approximately 4 psi (28 kPa).
2.4 When proper adjustment is obtained,
tighten the adjusting screw locknut and
install the cover. The pressure range be-
tween cut-in and cut-out is not adjustable.
Cut-In Position
Apply soap solution around the cover and to the ex-
haust port. Slight bubble leakage is permitted. Exces-
sive leakage indicates either a faulty inlet valve or
lower piston O-ring.
Cutout Position
Apply soap solution around the cover and to the ex-
haust port. Slight bubble leakage is permitted. Exces-
sive 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
leakage is excessive, it is recommended that it be
replaced with a new or remanufactured unit, or re-
paired with genuine Bendix parts.
42–03 Hydraulic Brake Lining
Wear Checking
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.
1. Chock the tires on the axle that isn’t being
worked on.
2. Remove the wheel and tire assemblies from the
axle that is not chocked.
3. 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, re-
move any remaining dust. Do not use com-
pressed air or dry brushing to clean the brake
assembly.
4. Measure the thickness of the brake pads at each
end of the raised axle. Replace all of the pads at
both axle ends if any of the linings is worn to
less than 3/16 inch (4.8 mm) at the thinnest
point.
5. Make sure that the brake rotor and linings are
free of oil and grease.
Brakes
42
Saf-T-Liner C2 School Bus Maintenance Manual, November 2020
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