“Air disc brakes offer quick and easy pad changes – about 15 minutes once the wheel is removed – and don’t require regular lubrication,” said Kevin Pfost, Technical Services Coordinator, Bendix Spicer Foundation Brake LLC (BSFB). “Faster service times equal greater vehicle uptime, as do the longer life cycles of air disc brakes.”
Out with the Old
Prepping for an air disc brake pad change is simple in that the brakes are the same whether they are equipped on a steer, drive, or trailer axle.
If the parking brake is on, it will need to be released or caged so that the axle rotates freely.
Once the wheel is off, exposing the wheel-end, find and remove the cap covering the shear adapter on the brake caliper. Using a 10 mm socket wrench or a ratcheting box wrench on the adapter, turn the adjuster counterclockwise – a clicking noise indicates that the tappets are “backing off,” or loosening the pads’ grip on the brake rotor – until it stops. A chain connects the pair of tappets to extend and retract them simultaneously.
“It’s important never to turn the adjuster without the shear adapter installed,” Pfost noted. “The shear adapter is designed to fail in the event of over-tightening, preventing damage to the adjustment mechanism itself. The adjustment mechanism is not replaceable, so if it goes bad, the entire caliper will need to be replaced.”
