User manual BENDIX M-12-M-12R ANTILOCK MODULATOR

[. . . ] ® Bendix® M-12TM & M-12RTM AntiLock Modulator 4 PIN CONNECTOR COVER PLATE SUPPLY PORT DELIVERY PORTS 2 VERTICAL 2 HORIZONTAL CONTROL PORT DELIVERY PORTS 4 VERTICAL SUPPLY PORT WIRE HARNESS 3 PIN CONNECTOR CONTROL PORT M-12TM Modulator FIGURE 1 M-12TM AND M-12RTM MODULATORS M-12RTM Modulator designed for direct controller mounting while the M-12RTM modulator uses a cover plate where the controller would normally mount and a wire harness is attached to the M-12RTM modulator in order to connect it to the antilock controller. Two body styles are available; one with four vertical delivery ports and another with two vertical and two horizontal delivery ports. The M-12TM/M-12RTM modulator is normally mounted close to the service actuators it serves, and it can be nipple mounted to a reservoir or secured to the frame rail. The M-12TM modulator air connections are as follows: M-12TM/M-12RTM Modulator Air Connection Supply (to reservoir) Delivery (to brake actuator) (can have 2 horizontal & 2 vertical deliveries or 4 vertical deliveries) Control (to rear service brake valve delivery) Embossed Identification SUP DEL DESCRIPTION The M-12TM antilock modulator is a standard component in Bendix antilock systems. [. . . ] Proceed to the modulator in question and identify it as an M-12TM or M-12RTM modulator and inspect its wiring connector. In the case of an M-12TM modulator it will be necessary to remove the four cap screws that secure the controller to the modulator. The M-12RTM modulator has an external connector that can be tested without removing the cover. Disconnect the connector and test the resistance between the pins on the modulator. Refer to figure 7. Note: If the resistance readings for the three pin connector are NOT as shown, the wire harness leading to the to the under side of the modulator cover may require repair or replacement. Remove the cover (as discussed elsewhere in this manual) and disconnect the four pin connector and perform the tests shown for the FOUR pin connector. If the resistance is correct at the four pin connector the short wire harness between the four and three pin connectors is at fault. If the resistance values are NOT AS SHOWN, replace the modulator. WARNING!PLEASE READ AND FOLLOW THESE INSTRUCTIONS TO AVOID PERSONAL INJURY OR DEATH: When working on or around a vehicle, the following general precautions should be observed at all times. Park the vehicle on a level surface, apply the parking brakes, and always block the wheels. Always wear safety glasses. 5 DOUBLE CHECK EXHAUST SOLENOID SUPPLY SOLENOID TRAILER CONTROL BRAKE VALVE CONTROL PISTON RESERVOIR DELIVERY SUPPLY EXHAUST SERVICE BRAKE CHAMBER FIGURE 6 ANTILOCK MODE: SOLENOIDS ACTIVATED 2. Stop the engine and remove ignition key when working under or around the vehicle. When working in the engine compartment, the engine should be shut off and the ignition key should be removed. Where circumstances require that the engine be in operation, EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically charged components. Do not attempt to install, remove, disassemble or assemble a component until you have read and thoroughly understand the recommended procedures. Use only the proper tools and observe all precautions pertaining to use of those tools. If the work is being performed on the vehicle's air brake system, or any auxiliary pressurized air systems, make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle. If the vehicle is equipped with an AD-ISTM air dryer system or a dryer reservoir module, be sure to drain the purge reservoir. Following the vehicle manufacturer's recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle. Never exceed manufacturer's recommended pressures. Never connect or disconnect a hose or line containing pressure; it may whip. Never remove a component or plug unless you are certain all system pressure has been depleted. 8. [. . . ] Install gasket(1) onto the controller or cover plate. If installing a controller, connect the four pin connector on the solenoid assembly(3) to the corresponding connector on the controller making certain the connector halves snap and lock. If installing a cover plate, make certain the "pinch" grommet on the short wire harness is in one of the two "notches" in the solenoid assembly(3) so that when the cover plate is installed the wire harness will not be pinched. Note the relationship mark made in step 2 of the disassembly, then secure the controller or cover plate to the solenoid assembly(3) using the four cap screws. [. . . ]