TRUCK SERVICE MANUAL
BRAKES-AIR
Fig. 3. Cutaway View of AE-1 Alcohol Evaporator
CONSUMPTION OF ALCOHOL
Example: If a compressor on a tractor-trailer will be
loaded (compressing air) 20% of the total operating time
Complaints of inoperative alcohol evaporator or
of 12 hours (or roughly 2-1/2 hours), consumption of
excessive use of alcohol can be traced to either a wrong
alcohol can be calculated by multiplying 70 cc of alcohol
kit being installed or an incorrect installation of a kit. For
(maximum usage) by 2.5 hours, or approximately 175 cc
that reason the correct selection of a kit is very
of alcohol (1/3 to 1/2 pint) in 12 hours. Additional
important.
calculations reveal that if a compressor operates a
greater percentage of time, more alcohol will be used.
The consumption of alcohol will vary on different
vehicles. The main determining factor on properly
TYPE OF ALCOHOL TO BE USED
installed and maintained units is the percentage of time
It is recommended that only pure methanol alcohol
the air compressor is in its loaded (compressing) cycle.
be used in the air brake system. Certain types of alcohol
Since the alcohol is only used when the compressor is
and antifreeze solutions contain ingredients which leave
compressing air, good maintenance practice should be
residue or deteriorate parts in the air system.
followed by keeping air leakage in the system to a
minimum and keeping the brakes adjusted.
Bendix Heavy Vehicle System Group markets
alcohol under the name "Air Guard."
It is difficult to estimate the amount of alcohol a
vehicle will use. A guide to determine if the alcohol
1 Qt. Can Part No. 242100
evaporator is working properly is:
1 Gal. Can Part No. 246972
Alcohol Usage =
30 cc to 70 cc
(1 oz to 2 ozs) per
hour if compressor
is continuously
pumping.
170