User manual BENDIX FD-2 CLUTCH TYPE FAN DRIVE

[. . . ] When the engine coolant temperature reaches the setting of the control valve, the valve exhausts air from the piston cavity. The fan clutch springs force the piston and pressure plate forward on the shaft. When the lining contacts the fan plate, the fan is engaged and is driven by the engine (see Figure 4). FIGURE 3 THERMO-PNEUMATIC VALVE Depending upon optional equipment installed on the vehicle such as radiator shutters and radiator mounted air conditioning condenser, different piping arrangements are necessary. These will be explained in the paragraph on control systems. DISENGAGED When the vehicle is started with a cold engine the thermopneumatic control valve is open. [. . . ] LEAKAGE CHECKS In order to check for air leakage past the only two sliding o-rings in the FD-2TM fan clutch it is necessary to disconnect the single air control line. reservoir (Bendix part number 225000) with a gauge installed to the control port of the fan clutch. reservoir with 100 psi, allow the pressure to stabilize and observe the time required for the reservoir pressure to drop to 90 psi. If the time required is less than 1 minute, leakage is excessive and repair or replacement is necessary. SERVICE CHECKS Before performing the operating and leakage checks, apply the vehicle parking brakes or chock the wheels. With the engine cold, the ignition off and at least 75 psi air pressure in the brake system, note that the fan is disengaged from the pulley and can be turned by hand. Drain all reservoirs and disconnect the air control line leading to the fan clutch and apply at least 75 psi shop air pressure to the fan clutch. If the fan cannot be turned, the clutch is defective and must be repaired or replaced (see appropriate section of this manual). If the fan can now be turned; check the air lines leading to and from the thermostatic control valve for "kinks" or obstructions, and check the control valve itself according to the manufacturer's instructions. After performing Step #1, drain all air pressure from the brake system. If it can be turned, the clutch is defective and must be repaired or replaced. Check the operation of the thermostatic control valve by running the engine up to operating temperature. Note that the fan clutch engages when engine temperature rises to normal or above and disengages after fan cooling is accomplished. If this test is being performed for the first time after installation of the fan clutch, recheck the setting of the thermostatic control valve and compare it with the setting of the engine coolant thermostat or in the case of vehicles with radiator shutters, with the setting of the shutter control. 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. 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. [. . . ] Install piston (16) into piston housing (15) and install unit onto shaft. Install fan plate assembly (20) onto shaft and retain with lock nut (3). With no air pressure applied, the torque required to rotate the clutch must not exceed 150 inch ounces. With 70-75 psi applied, the fan plate must rotate freely, separate from the pulley. [. . . ]