User manual BENDIX A2LS HYD DRUM BRAKES W-PARKING

[. . . ] ® Bendix® A2LSTM Hydraulic Drum Brakes w/Parking DIRT SHIELD CROSS-OVER PIPE RETAINING SPRING CROSS-OVER PIPE WHEEL CYLINDER END SHOE RETURN SPRING CAP SCREWS EXPANDER END SHOE RETURN SPRING WHEEL CYLINDER GASKET GROMMETS SHOE HOLD-DOWN CLIP (NOT FITTED TO EARLY BRAKES) EXPANDER FIGURE 1 - A2LSTM AUTOMATIC ADJUSTING TWO LEADING SHOE DRUM BRAKE DESCRIPTION The A2LSTM drum brake is a hydraulically operated duo-duplex brake with an automatic adjustment and parking brake feature. The A2LSTM drum brake (automatic adjust, two leading shoes) provides two leading shoes in either direction of drum rotation and an automatic adjustment of the brake shoes to compensate for lining wear. Both the wheel cylinder unit and expander unit have cast integral brake mounting lugs, each taking the brake torque load. The wheel cylinder unit contains two single acting hydraulic cylinders with automatic adjusters. [. . . ] Slowly release the spring pressure and remove spring along with the ferrule. Use snap ring pliers to compress and remove the circlip (snap ring), Figure 17. Remove the dust boots from both ends of the expander housing and discard. Note: The dust boots should not be reused and must be replaced. Remove the abutment tappet, input tappet/ piston and stop pin from the housing. Remove the wedge assembly, wedge seal, retaining ring assembly and washer. Push the roller tappet/piston from the housing in the direction of the input tappet/piston, Figure 17. Note: Do not slide the roller tappet/piston past the wedge turret. Using a small screwdriver, with the end rounded and polished, pry the seals and o-ring from the input and roller tappet/piston taking care not to score the seal grooves or piston surface. DOT 4 FLUID DOT 4 FLUID DOT 4 FLUID GREASE GREASE CLEANING AND INSPECTION Discard all of the old parts that are to be replaced with parts furnished in the repairs kits. Clean all of the metal parts with unused DOT 4 brake fluid or suitable solvent. Do not use gasoline or hot water solution on metal parts. GREASE FIGURE 18 - EXPANDER LUBRICATION POINTS 9 TAPPETS LOCATED OVER WEDGE, CAGE & ROLLER ASSY. 7. Clean the backing plate with a damp cloth and wire brush to remove any dirt or corrosion from the surface of the backing plate. IMPORTANT!PLEASE READ: Do not use an air hose to blow dust out of the backing plate (dirtshield). Never inhale dust from asbestos brake lining. Asbestos dust, when inhaled, can be dangerous to your health. Use a vacuum with a filter to remove dust carefully from the backing plate and drum. Refer to the vehicle service manual for inspection and resurfacing procedures. Wipe drum clean with a cloth dampened in Bendix Metal Clene. Do not contaminate the braking surface of the drum with grease or brake fluid. REASSEMBLY STOP PIN FIGURE 19 - EXPANDER TAPPET LOCATION Note: Normal wear pressure marks should not be mistaken for scoring. Some discoloration of the piston diameter may be apparent; this is a normal result of brake actuation over a long period of operation and should be ignored. Check the helix for burrs, corrosion, or missing teeth. [. . . ] Incorrect linings or lining loose on shoes. Loose or distorted backing plate (dirtshield). 14 1. Replace with correct shoes in axle sets. Replace with correct shoes in axle sets. [. . . ]