Chevrolet 30 Series 1967 Service Manual page 262

BRAKES 5-48
purposes use either recommended brake fluid or Di-
Acetone alcohol. Discard fluid after flushing.
CAUTION: Use care when filling hydraulic sys­
tem to prevent dirt from entering through top of
master cylinder.
The air brake system (fig. 78) completely replaces
all hydraulic brake components with air brake parts for
producing and utilizing greater braking forces. The air
compressor in the all air brake system builds up and
maintains the air pressure required to operate all of the
air powered devices.
A pressure protection valve is installed between the
COMPRESSOR
The Tu-Flo 400 and 500 compressors are single stage
reciprocating piston type compressors. Both the 400 and
500 compressors have two cylinders.
5000 Miles:
Depending on operating conditions and experience,
service the compressor air strainer. Remove and wash
all parts. Strainer element should be cleaned or replaced.
AIR BRAKES
GENERAL DESCRIPTION
MAINTENANCE AND ADJUSTMENTS
Fig . 78—A ir Brake System
A manifold check valve is installed in the vacuum line
running from the engine intake manifold to the front
chamber of the booster unit.
primary air brake system and the auxiliary air operated
accessories. A minimum air pressure of approximately
80 psi is required to lift the valve diaphragm off its seat
and permit air to pass to the accessories. Should the air
pressure drop below 80 psi, the diaphragm closes off all
air to the accessories and all remaining air pressure is
reserved for the brake system.
If the element is cleaned, it should be washed in gasoline,
methyl alcohol, carbon tetrachloride, or soap and water.
The element should be saturated in clean engine oil then
squeezed dry before replacing it in the strainer.
Check compressor drive alignment belt tension and
note that all mounting bolts are securely fastened.
35,000 Miles:
Remove compressor discharge valve cap nuts and
check for presence of excessive carbon deposits. Also,
CHEVROLET TRUCK SERVICE M ANUAL