Universal Full Empty
Please review Brake Wear Indicator details page.
Brake cam rotation measures brake wear. Brake wear begins with rollers at ZERO degrees and ends at 120 degrees. Back the camshaft off until the rollers are deep in the saddle of the S-cam that is ZERO. S-Cam brakes are out of service at 120 degrees of cam rotation as shown above.
Use a straight edge between the center of the yoke pin in the slack adjuster and the center of the S-Cam. Scribe a mark on the S-Cam face, then make it permanent with a hammer and cold chisel.
Remove the snap ring and outer spacer washer at the slack adjuster face. Replace the washer with the Brake Wear Indicator meter. Re-install the snap ring.
With the brake drum and linings in place, Adjust the brake as normal.
In spection is as easy as rotating the meter, (with park brakes released) lining up the external arrow with the ZERO degree timing mark. Count back to a straight line between the adjuster yoke pin and center of the S-Cam with each index mark on the plate being 3 degrees. Then add 5 degrees to include shoe to drum clearance in the measurements.