Loosen and remove the four screws securing
the left front console to the dash.
Using the wrench flat closest to the threaded
Pull out the left front console enough to gain
end, screw the valve into the fitting.
access to the rear of the air pressure gauge. Loosen
the two fittings and tag and remove the nylon tubes
Operating and Leakage Checks
from the rear of the gauge
With air pressure in the system, pull the exposed end
Remove the hardware securing the gauge to
of the valve stem removing the spring load from the
the front console and remove the gauge.
ball check valve. Air should exhaust from the valve's
exhaust port. Release the stem, and the air flow
should stop. Failure of the valve to pass the
operating test would indicate the valve should be
Install the air pressure gauge into the front
repaired or replaced.
console using the attaching hardware.
Coat the exhaust port with a soap solution. A
Install the two nylon tubes to the fittings in the
leakage of a one inch bubble in five seconds is
rear of the gauge as tagged during removal.
permitted. Excessive leakage indicates dirt in the
valve or a faulty ball valve or seat. If excessive
Secure the front console to the dash using the
leakage is indicated, the valve should be repaired or
Connect the batteries as tagged previously.
AUTOMATIC DRAIN VALVE
Start the engine and observe the air pressure gauge.
The automatic drain valve is designed to eject
The green arrow on the gauge (primary) should rise
moisture and contaminates from the air system
first until a pressure reading of approximately 95 psi
reservoir upon a slight reduction in reservoir
(655 kPa) at which time the red arrow (secondary)
pressure. It operates automatically from ascending
should begin to climb. Both arrows should level off
and descending reservoir pressures, has only one
at approximately 110 psi (7584 kPa).
moving part, and requires no manual assistance of
control lines from other sources. The valve has a
die cast aluminum body and cover.
Chock the vehicle wheels.
A safety valve is installed in the top of the supply
reservoir to protect the air system against
Deplete all pressure in both air systems.
excessive air pressure buildup. The valve consists
of a spring loaded ball valve subjected to reservoir
Remove the drain valve from the bottom port
pressure which permits air to exhaust from the
of the reservoir.
reservoir to the atmosphere if the pressure rises
above 150 psi (1034.3 kPa/1 0.3 bar). This
pressure setting is nonadjustable and is determined
by the force of the spring.
To prevent early plugging of the drain valve
filter, thoroughly flush and clean the reservoir before
installing the drain valve.
Chock the vehicle wheels.
Aerate the reservoir thoroughly if any solvents
Deplete the pressure in both air systems.
have been used to clean the reservoir.
Using the wrench flat, closest to the reservoir,
Install the drain valve in the bottom port of the
unscrew the valve from the fitting on the reservoir.
reservoir and tighten.