Checking the Relay Valve, Midland

Chock the tires. Start the engine and run it long enough to pressurize the air system to at least 80 psi (550 kPa), then shut down the engine.

Repeat as necessary, to maintain 80 psi (550 kPa) pressure during this check.

Clean off road grime from the relay valve, and any debris from the valve exhaust port. Listen for air leakage around the fittings or exhaust port. Tighten the fittings as necessary. Use two wrenches to avoid twisting the tubing.

If the valve fails this check, or is damaged, repair or replace it; see the Midland Service Manual for instructions.