User manual BENDIX M32 M32QR ANTILOCK MODULATOR ASSY

[. . . ] The supply, delivery and exhaust ports on the M-32TM modulator are identified with a cast, embossed numeral for positive identification. Identification Air Line Connection 1, SUP Supply (incoming air from foot, relay or quick release valve) 2, DEL Delivery (air delivery to service actuators) 3, EXH Exhaust SD-13-4870 1 Front Axle Systems Wheel Control Service Brake Chamber To Antilock Controller M-32QR TM Modulator To Antilock Controller M-32 TM or M-32QRTM Modulator To Antilock Controller Wheel Control Axle Control Rear Axle System Wheel Control To Antilock Controller M-32TM or M-32QRTM Modulator or or Controller/Relay Assembly M-32TM or M-32QR TM Modulator To Antilock Controller M-32TM or M-32QRTM Modulator Quick Release Valve M-32QR Modulator TM To Antilock Controller Service Brake Chamber M-32TM or M-32QRTM Modulator To Antilock Controller Quick Release Valve Service Brake Chamber Service Brake Chamber Service & Spring Brake Chamber FIGURE 3: TYPICAL WHEEL AND AXLE CONTROL SYSTEMS NOTE: use of a quick release valve is not typically required with the M-32QRTM modulator. Refer to vehicle specifications for recommended configuration. FUNCTIONAL CHECK A wiring harness connects the vehicle modulators to the controller. The ABS controller is able to simultaneously and independently control the individual modulators. [. . . ] In order to control the brake application, the coils of the two solenoid valves contained in the modulator are energized or de-energized in a preprogrammed sequence by the antilock controller. When a solenoid coil is energized, and depending whether the exhaust or hold solenoid is energized, it either 4 ANTILOCK HOLD MODE (Figure 9) The antilock controller will place the modulator in the Hold position when it senses that the correct wheel speed (braking force) has been attained. The antilock controller will also Brake Valve Supply Port Delivery Port Brake Valve Brake Chamber Supply Port Bias Valve Delivery Port Supply or Hold Diaphragm Closed Spring Exhaust Valve Open Solenoid Energized: Exhaust Moves to Down Diaphragm Position Brake Chamber Supply or Hold Diaphragm Spring Exhaust Valve Solenoid Energized: Moves to Exhaust Down Port Position M-32TM Modulator Solenoid Energized: Moves to Down Position Exhaust Port Solenoid Energized: Moves to Exhaust Down Diaphragm Position M-32QRTM Modulator FIGURE 8: M-32TM MODULATOR ANTILOCK EXHAUST OF BRAKES Brake Valve Supply Port Delivery Port Brake Valve Brake Chamber Supply Port Bias Valve Delivery Port Supply or Hold Diaphragm Closed Spring Exhaust Valve Closed Brake Chamber Supply or Hold Diaphragm Spring Exhaust Valve Solenoid Energized: Exhaust Moves to Port Down Position Exhaust Diaphragm Solenoid Returns to Up Position M-32TM Modulator Solenoid Energized: Moves to Exhaust Down Position Port Exhaust Diaphragm Solenoid Returns to Up Position M-32QRTM Modulator FIGURE 9: M-32TM AND M-32QRTM MODULATORS ANTILOCK APPLICATION HELD POSITION place the modulator in the hold position, prior to entering the reapply mode, when it detects recovery from a locked wheel condition. In this mode of operation, the modulator supply/hold solenoid remains energized while the exhaust solenoid returns to its normal position. The exhaust solenoid allows application air to flow to the control side of the exhaust diaphragm, which then seals the exhaust passage. With the exhaust diaphragm seated, further exhaust of brake chamber air pressure is prevented. Because the supply solenoid remains energized, the supply diaphragm remains seated, thus preventing application air from flowing to the delivery port and out to the brake chamber. Build system pressure to governor cut-out and turn the engine OFF. After determining the pressure loss with the brakes released (2 PSI/minute allowed), make and hold a full service brake application. Allow the pressure to stabilize for one minute. Begin timing pressure loss for two minutes while watching the dash gauges for a pressure drop. The leakage rate for the service reservoirs should not exceed 3 PSI/ minute. If either circuit exceeds the recommended two PSI/ minute, apply soap solution to the exhaust port of the modulator and any other components in the respective circuit. The leakage at the exhaust port of most Bendix components, including M-32TM modulators, should not exceed a one-inch bubble in three seconds. If leakage at the modulator is determined to exceed the maximum limits, replace the modulator. ELECTRICAL TESTS 1. Before testing the solenoid assembly of a suspect modulator, its location on the vehicle should be confirmed using the Trouble Shooting or Start Up procedure for the specific antilock controller in use. (See the Service Data Sheet for the antilock controller for this procedure. ) 2. Proceed to the modulator in question and inspect its wiring connector. Disconnect the connector and test the resistance between the pins ON THE MODULATOR. HOLD TO SOURCE (41-42): Read 4. 9 to 5. 5 Ohms. EXHAUST TO SOURCE (43-41): Read 4. 9 to 5. 5 Ohms. EXHAUST TO HOLD (43-42): Read 9. 8 to 11. 0 Ohms. [. . . ] Locate the modulator that will be replaced and clean the exterior. Identify and mark or label all air lines and their respective connections on the valve to facilitate ease of installation. Disconnect both air lines and the electrical connector. These fittings will be re-used in the replacement modulator. 7 Port Designation Supply 1 Delivery 2 Exhaust 3 Electrical Control Source Hold Exhaust 41 42 43 FIGURE 11: M-32TM AND M-32QRTM MODULATORS DIN SYMBOL MODULATOR INSTALLATION 1. [. . . ]