Meritor Cam-Main® Q Plus Brakes

Cam-Main brakes are air-actuated, cam-operated, foundation brakes. The Q Plus increases service life and mileage between relines by providing more lining thickness. A specially designed S-cam and heavy-duty shoe return spring allow additional shoe travel required to fully wear the thicker lining blocks. An improved camshaft bushing contributes to longer service life.

Cam-Main Q Plus Operation

When the brake pedal is depressed, compressed air enters the brake chamber, causing the diaphragm to move a pushrod assembly.

The pushrod turns the slack adjuster and brake camshaft. As the camshaft turns, the S-type cam head forces the brake shoes against the brake drum and braking occurs.

When the brakes are released and air is exhausted from the brake chamber, the actuator return spring (within the brake chamber) and the brake shoe return spring return the camshaft, brake shoes, slack adjuster, and pushrod to their released positions.