PARKING BRAKE CONTROL (SUPERSTRUCTURE CAB)
Ensure battery disconnect switch is in the OFF position.
Relieve air system pressure by draining supply (depress pin in center of automatic drain valve), secondary,
and auxiliary air reservoirs.
Remove retaining nut (5), shim washer (6) and push control assembly (7) from dash panel.
Tag and disconnect air lines (1 and 2) from elbows (8 and 9).
If necessary, remove elbows (8 and 9) from control assembly (7).
Connect air lines (1 and 2) on elbows (8 and 9) and remove tags.
Position control assembly (7) in dash panel and secure with retaining nut (5) and shim washer (6).
Install knob (4) on control assembly (7) and tighten setscrews (3).
Close drain valves on air reservoirs.
Operating and Leakage Check
If the park brake control valve does not operate as described, or leakage is
excessive, it is recommended that it be replaced.
Chock the wheels and fully charge the air system.
With the PARK BRAKE control pulled out (exhaust position), coat the exhaust port and plunger stem with a
soap solution. A 1 in. (254 cm) bubble in five seconds is permitted. There should be no leakage between the
upper and lower body.
Push the PARK BRAKE control in (applied position).
A 1 in. (254 cm) bubble in three seconds is
Reduce system air pressure and observe the PARK BRAKE control. It should pop out when the air
pressure drops to approximately 40 psi (275 kPa), exhausting the delivery line and engaging the park brakes.