Chevrolet 10 Series 1968, Руководство по обслуживанию

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BRAKES 5-96
F ig . 1 3 9 -Emergency A ir Brake V a lv e s, Fittings and Pipes
buzzer and gauge indicate failure simultaneously, the
problem is in the primary system. Should the buzzer
sound with the gauge continuing to show normal pressure,
the difficulty is in the secondary system.
Whenever a valve or component is disassembled, it
should be cleaned and inspected.
Cleaning and Inspection
1. Wash all metal parts in a good cleaning solvent. Rub­
ber parts should be wiped clean.
2. Inspect all parts for excessive wear or deterioration.
3. Check springs for cracks, corrosion, or distortion.
4. Inspect piston valve seats, body bores and gasket
surfaces for nicks or burrs.
5. Replace all parts not considered serviceable during
these inspections.
AIR COMPRESSOR AND GOVERNOR
(BENDIX-WESTINGHOUSE TU-FLO TYPE)
The Tu-Flo 400 and 500 compressors are single stage
reciprocating piston type compressors. Compressors
can be readily identified by referring to name plate at­
tached to cylinder block. All 500 compressors have
water cooled cylinder heads and water cooled cylinder
blocks. All 400 compressors are air cooled. Governor,
acting in conjunction with air compressor unloading
mechanism, controls compression of air. The governor
used on the compressor is set at a maximum of 125 psi
and a minimum of 105 psi. On belt driven air compres­
sors the crankshaft is mounted in crankcase on a ball
bearing in front and an insert type bearing in rear (See
Figure 141).
BRAKE CONTROL VALVE
Every 200 operating hours or after 5,000 miles or once
each month, lubricate pedal mechanism. Also check the
lever's linkage for adjustment and/or binding.
Every 3,600 operating hours or after each 100,000
miles, or yearly, it is recommended that the inlet and ex­
haust valves, exhaust diaphragm, "O" rings and rubber
parts and graduating spring be replaced if they show signs
of wear or distortion.
Every 7,200 operating hours or after 200,000 miles, or
every two years, disassemble brake valve, clean and in­
spect all parts. Install new parts where they are found to
be worn or damaged.
MANUAL AND EMERGENCY CONTROL VALVE
About once each year the Emergency Control Valve
should be disassembled and cleaned.
DOUBLE CHECK VALVES
Once a year or every 50,000 miles, the check valve
should be removed, dismounted, and cleaned.
DD2 SAFETY ACTUATOR
Every month or after 2,000 miles depending on type of
operation.
1. Check actuator push rod travel and adjust travel at
the slack adjuster if needed. Push rod travel should
be kept as short as possible without brakes dragging.
Excessive push rod travel reduces braking efficiency,
shortens diaphragm life, gives slow braking response
and wastes air.
2. Check push rod to slack adjuster alignment in both
the applied and released positions to be sure the push
rod moves out and returns properly and without bind­
ing. Also check the angle formed by the slack ad­
juster arm and push rod. It should be 90° or greater
when the chamber is in the applied or released po­
sitions.
3. Check tightness of mounting bolts. Check cotter
pins to make sure they are in place. Check that
drain holes are open.
Every year or after each 50,000 miles, depending on
type of operation.
1. Disassemble actuator and clean all parts.
2. Install new diaphragm, or any other rubber parts, if
they are worn or deteriorated.
NOTE: When the diaphragm or spring or both
are replaced, they should be replaced in the
corresponding actuator on the same axle.
DOUBLE CHECK VALVE & STOP LAMP SWITCH
Every month or after 10,000 miles, check the elec­
trical connections and the operation.
Every year or after 50,000 miles, the combined stop
light switch and double check valve should be disas­
sembled and cleaned. Rubber parts and other parts
subject to wear should be replaced if worn or damaged.
TRACTOR PROTECTION VALVE
Once each year, or depending on experience, the
Trailer Emergency Control and Tractor Protection
Valves should be thoroughly checked both operationally
CHEVROLET TRUCK SERVICE MANUAL