If your vehicle has air brakes, you will have this parking brake. It is located above the radio in the instrument panel.
Pulling it out applies the parking brake. The parking brake light will come on when the air parking brake is applied.
Vehicles built for use as tractors or towing vehicles have two air brake controls. They look like this:
Caution: When the yellow PARKING BRAKE and the red TRAILER AIR SUPPLY knobs are both pushed in, the rig will be free to move. It could strike someone or something. When both of these knobs are pushed in, hold the regular brake pedal down to keep the rig from moving.
To charge a trailer's air brake system do the following:
- Move your vehicle into the proper position.
- Apply the parking brake by pulling the yellow parking brake knob out.
- Hook up the trailer air system properly.
- Get into the vehicle.
- Push and hold down the regular brake pedal.
- Push in both the yellow parking brake and the red trailer air supply knobs. This will charge your trailer's air system.
After a few minutes, the trailer system should be fully charged. When it is, the air pressure gage will show about 125 to 135 psi (862 to 931 kPa). See Air Pressure Gage for more information.
For driving with a trailer, the yellow and red, if equipped, knobs must be pushed in. When you are not pulling a trailer, the red trailer air supply knob must be pulled out.
Caution: If you apply any one of the air brake parking controls while the vehicle is moving, the rig will stop suddenly. If you are not ready for this, you or others could be injured. Do not apply any one of these controls while you are driving, unless you have to make an emergency stop.
If the air pressure drops below 60 to 70 psi (413 to 482 kPa), the primary brake light and warning buzzer will come on. If the air pressure drops to 35 to 45 psi (241 to 310 kPa), the red trailer air supply knob will automatically pop out and apply the spring brakes on the trailer.
If the air pressure drops to 35 to 45 psi (241 to 310 kPa), the yellow park brake knob will automatically pop out and apply the spring brakes on the truck or tractor.
If you ever have a complete loss of air so that your air brakes automatically apply, there is a way that the tow operator can release the parking brakes to tow the vehicle. See Towing Your Vehicle .
