- The brake pedal is used to apply the service brakes.
- Spring brake chambers include both service brake and spring brake sections.
- The large coil spring inside a spring brake chamber is under high tension and can be hazardous.
- When the spring in a spring brake chamber is compressed or ‘caged’, it looks different and the spring brake will not apply.
- A spring brake control valve is normally a push/pull type valve fitted with a yellow, four-sided knob located near the driver.
- When the air brake system pressure falls below its normal operating range (normally 414 kPa or 60 psi), the spring brakes will begin to apply automatically.
- If brakes are out of adjustment, the spring brakes may not stop or hold a vehicle.