FOUR-WAY AIR SOLENOID VALVE
The four-way air solenoid valve installed in the air system allows the operator to engage or release the parking
brake from either cab regardless of the position of the PARK BRAKE control in the other cab. The air valve has
two solenoids, one connected into the circuitry of each cab to activate the valve. This means that only one
solenoid is powered at a time depending on which cab has electrical control (ignition switch on), thus giving that
cab and only that cab control of the parking brake.
Ensure battery disconnect switch is in OFF position.
Relieve air system pressure by draining supply (depress pin in center of automatic drain valve), secondary,
and auxiliary air reservoirs.
Disconnect electrical connector for four-way air solenoid valve (8, Figure 2-7-14).
There may be residual pressure in air lines after air reservoirs are
drained. Wear eye protection when disconnecting air lines to prevent
Loosen clamps (1), tag, and disconnect air hoses (2) from air fittings on four-way air solenoid valve (8).
Tag and disconnect air lines from elbows (9 thru 13).
Remove nuts (5), lockwashers (6), washers (7), and four-way air solenoid valve (8) from mounting studs.
Note that ground wires are installed under one nut (5).
If necessary, note position of 45 elbows (11 and 13) and remove elbows (9 thru 13) from valve.
If removed, install elbows (9 thru 13, Figure 2-7-14) in four-way air solenoid valve (8). Ensure 45 elbows
(11 and 13) are installed in ports noted during removal.
Position four-way air solenoid valve (8) on mounting studs and secure with washers (7), lockwashers (6),
and nuts (5). Secure ground wires on right side mounting stud under one nut (5) as removed.
Connect air lines to elbows (9 thru 13) and remove tags.
Install air hoses (2) on valve air fittings and tighten clamps (1). Remove tags.
Connect four-way air solenoid valve (8) electrical connector.
Close air tank drain valves.