The disc brake chamber is an essential part of the air-brake system. It transfers compressed air from the master cylinder and drives the brakes to stop your wheels. The chamber has a pushrod, a diaphragm and a return spring.

Brake chambers come in a range of sizes, including 16, 20, 24 and 30. They also have either standard or long-stroke configurations.

Inspect the Diaphragm and Pushrod for Damage
Several factors can affect the condition of the chambers. For example, a rotor or disc that is warped or damaged could cause the brakes to fade out.

Inspect the Pushrod for Out-of-Adjustment
Many air brake chamber pushrods today feature an indicator marking that can tell you if a brake is out of adjustment. The indication is usually a brightly colored band around the pushbar. If the indication is not visible, it means the brake is within the adjustment limits and can be safely operated.

Checking the Diaphragm for Out-of-Adjustment
Using an accurate tool, measure the distance between the chalk mark on the pushrod and the face of the brake chamber. This is called the applied pushrod stroke and is a reliable method for inspecting brake adjustment.

It's important to note that this is a limited inspection method and does not give you a complete picture of brake adjustment. It's a good idea to do a comprehensive inspection of all of the brake chambers in your vehicle to verify that each one is within CVSA adjustment limits.