Identifying Brake Types

There are two different types of drum brake systems used on C/K trucks Leading/Trailing and Duo Servo. The two systems can be identified without removing the rear wheels by noting the position of the adjustment slot.

Exploded View Of Adjusting Screw Assembly:

Leading/Trailing Brakes: Pushing Release Lever Off Its Stop:

Leading/Trailing
On the Leading/Trailing brake system the adjustment screw assembly is located directly below the wheel cylinder. The adjustment slot is located parallel to the top of the axle tube.

Fig. 1 Exploded View Of Drum Brake Assembly.:

Duo Servo
On the Duo Servo brake system the adjustment screw assembly is located at the bottom of the brake shoes. The adjustment slot is located near the bottom of the backing plate.