User manual BENDIX AIR DISC BRAKE-ADB22X-225-SN6-7-SK7

[. . . ] Bendix® ADB 22XTM, ADB 225TM, SN6TM, SN7TM, SK7TM Air Disc Brakes DESCRIPTION Bendix® Air Disc Brakes use a floating caliper design to provide foundation braking on all axles of heavy commercial vehicles, buses and trailers. Bendix Air Disc Brakes provide safety and performance, as well as ease of service. Available in models with or without a combination spring brake unit, these brakes may also include optional wear sensors and/or wear diagnostic equipment. OPERATION Bendix Air Disc Brakes convert air pressure into braking force. (See Figure 2. ) When the vehicle brakes are applied, air enters the service brake chamber through the supply port, applying pressure within the diaphragm. [. . . ] This guide pin inspection should be carried out if the result of the Caliper Movement Test (see Page 13) is that the technician cannot move the caliper. 13 Tappet and Boot 1 Assembly Caliper 5 Guide Pin 7 Brass Bushing 10 Cover LONG BEARING SIDE 23 Adjuster Unit 61 Shear Adapter 37 Adjuster Cap GUIDE PIN BEARING INSPECTION Use the following procedure to check caliper movement along the guide pins: Remove the Pads (see Page 18). One of the three different styles of guide pin (A, B, or C) may be present (See Figure 28). The bearings for styles A and B use a rubber bushing, and style C uses a guide sleeve. Using hand pressure only (no tools), the Caliper (1) should slide freely along the whole length of the Guide Pin arrangement. With the pads removed, this movement should be at least 0. 8 inch (20mm). If the movement is less than this amount, replace the caliper/carrier assembly. To measure the clearance from the rubber bushing (6a, 6b) or guide sleeve (6c) to the guide pin: See Figures 29 and 30. Remove the pad retainer (11), but leave the pads (12) in position. Attach a magnetic dial-gauge holder to the carrier (2) on the short bearing side of the caliper (1). Use the measuring point on the caliper (1) - see the arrow in Figure 28. Press the caliper in the direction of carrier (2) and set the dial-gauge to zero. screwdriver) between Carrier (2) and Caliper (1) forcing them in opposite directions, and read the maximum value on the dial-gauge. For styles A and B guide pins, if the value is greater than 0. 079 in. (2. 0 mm), or for style C guide pins, if the value is greater than 0. 039 in. (1. 0 mm), the caliper/carrier assembly must be replaced. 68a Cap SHORT BEARING SIDE Caliper Movement 39a 4a 6a (6a): Rubber Bushing (39a): Caliper Bolt (4a): Guide Pin (6b): Rubber Bushing (39b): Caliper Bolt (4b): Guide Pin 4b 6b 39b 6c Guide Sleeve 39c Caliper Bolt 4c Guide Pin 68c Cover FIGURE 28 - GUIDE PINS 12 Pad Assembly 1 Carrier 2 Caliper FIGURE 29 - MAGNETIC DIAL-GAUGE 16 GUIDE PIN SEAL INSPECTION Caliper Guide Pin Seals The long bearing side guide pin (5) is sealed with the cover (10) and with the inner boot (9). Note: It may be necessary to remove the pads to inspect the inner boots (9) if pad wear is minimal. The guide pin (4a, 4b, or 4c, depending on the style) is also sealed with an inner boot (9) and a cover (style C), or a flexible rubber wear indicator in the case of style A guide pins. Inspect the above components, and if damage is found, replace the caliper/carrier assembly. No kits are available at this time for Guide Pin Seals. 13 TAPPET AND BOOT ASSEMBLY INSPECTION In order to inspect the tappet and boot assembly, it may be necessary to remove the pads (12) (see Page 18) and advance the shear adapter (61) clockwise (see Page 15) until the boots are clearly visible. CAUTION: NEVER EXTEND THE TAPPET MORE THAN 1. 18 in. Over-extending the tappet will result in the tappet losing engagement with the threads of the synchronizing mechanism. Since the mechanism can only be set at the manufacturing plant, the CALIPER/ CARRIER ASSEMBLY MUST BE REPLACED if this happens. [. . . ] (3 mm) Spring Brake Removal CAUTION: Follow all standard safety procedures - see note above. Be familiar with the spring brake manufacturer's recommended safety practices. With all air pressure drained from the air brake system, disconnect the air hose from the brake chamber (18/1). Back out the release bolt (Figure 53, arrow D) using a maximum torque of 26 ft. [. . . ]