18Horton Fan Inspection Tech Tip

1. Check for Air Leaks Apply air pressure to the fan drive. Confirm that the vehicle’s air system reservoir and air lines are clean and dry and without restrictions. Check solenoid valve for proper operation. a) Listen for air leaks around the solenoid valve, filter assembly, air lines and fittings. b) Look for air leaks. Using a spray bottle, spray soapy water around the spring housing, sheave and bleed hole. Look for bubbles. Maintenance Procedure: If an air leak is present, repair the fan drive with the appropriate Horton repair kit or replace the fan drive with a remanufactured Horton fan drive or new fan drive. Clean and repair vehicle air system as required. 2. Check the Fan Drive Friction Surfaces Check air pressure to the fan drive. A minimum of 90 psi [6.2 bar] is required to fully disengage the fan drive. a) Inspect the fan drive friction facing for wear by measuring the thickness of the friction facing material. A new friction facing is 11 / 32 inch [8.51 mm] thick. Replace the friction facing material if it has worn to ¼ inch [6.35 mm] thick or smaller. The fan mounting friction disc (FMFD) may need to be removed to check liner wear on the two-speed version. b) Check the FMFD surface for wear, discoloration or other signs of overheating. Maintenance Procedure: - If excess wear is present, check engine control module (ECM) and air-conditioning (AC) runtimes. The fan and AC runtime should be set at 60-90 seconds or greater to reduce friction wear and engagements. - Check ECM programming of engine brake. The engine brake should be set to “Fan Off” when the engine brake is applied. - Check for fan obstruction or shroud interference. 3. Check the Fan Drive for Proper Engagement and Disengagement Set the ignition switch to “On” for the following procedures. But DO NOT start the engine. a) Manually engage and disengage the fan drive by disconnecting the electrical connector at the solenoid valve, opening and closing the solenoid valve. b) Remove the air supply to engage the fan drive by following the instructions above. Attempt to move the fan. If the fan rotates with minimal force, the friction surfaces are worn beyond use. Repair with the appropriate Horton repair kit or remanufactured or new fan drive. c) Check the electrical wiring at the thermal switch, air-conditioning pressure switch and the solenoid valve. Make sure there are no loose wires or connections. Maintenance Procedure: - If excess friction wear is present, repair the fan drive with the appropriate Horton repair kit or remanufactured or new fan drive. - If over-cycling of an on/off fan drive is resulting in excessive friction wear, a Horton DM Advantage ® Two-Speed or PolarForce ® Two-Speed Conversion Kit should be considered to replace an on/off fan drive when making the repair. Inspection Procedures FMFD IRON PULLEY ALUMINUM SPRING HOUSING FRICTION LINER MEASURE THIS DISTANCE TO DETERMINE WEAR and On/Off and Two-Speed Fan Drives and Horton Fans NOTE: All Inspection Procedures to be conducted with the engine off. Recommended 25,000-mile (40,000 Km) or 300-hour Preventive Maintenance (whichever comes first). Check area between pulley and clutch pack for air leaks Check bleed hole for air leaks Check for discoloration or other signs of overheating Inspect friction liner wear Signs of overheating TECH Tips 1. Check for Air Leaks Apply air pressure to the fan drive. Confirm that the vehicle’s air system reservoir and air lines are clean and dry and without restrictions. Check solenoid valve for proper operation. a) Listen for air leaks around the solenoid valve, filter assembly, air lines and fittings. b) Look for air leaks. Using a spray bottle, spray soapy water around the spring housing, sheave and bleed hole. Look for bubbles. Maintenance Proc ure: If an air leak is present, repair the fan drive with the appropriate Horton repair kit or replace the fan drive with a remanufactured Horton fan drive or new fan drive. Clean and repair vehicle air system as required. 2. Check the Fan Drive Friction Surfaces Check air pressure to the fan drive. A minimum of 90 psi [6.2 bar] is required to fully disengage the fan drive. a) Inspect the fan drive friction facing f r wear by measuring the thickness of the friction facing material. A new friction facing is 11 / 32 inch [8.51 mm] thick. Replace the friction facing material if it has worn to ¼ inch [6.35 mm] thick or smaller. The fan mounting fricti disc (FMFD) m y need to be removed to check liner wear on the two-speed version. b) Check the FMFD surface for wear, discoloration or other signs of overheating. Maintenance Procedure: - If excess wear is present, check engine control module (ECM) and air-conditioning (AC) runtimes. The fan and AC runtime should be set at 60-90 seconds or greater to reduce friction wear and engagements. - Check ECM programming of engine brake. The engine brake should be set to “Fan Off” when the engine brake is applied. - Check for f n obstruction or shroud interfere c . 3. Check the Fan Drive for Proper Engagement and Disengagement Set the ignition switch to “On” for the following procedures. But DO NOT start the engine. a) Manually engag and dis ngage the fan drive by disconnecting the electrical connector at the solenoid valve, opening and closing the solenoid valve. b) Remove the air supply to engage the fan drive by following the instructions above. Attempt to move the fan. If the fan rotates with minimal force, the friction surfaces are worn beyond use. Repair with the appropriate Horton repair kit or remanufactured or new fan drive. c) Check the electrical wiring at the thermal switch, air-conditioning pressure switch and the solenoid valve. Make sure there are no loose wires or connections. Maintenance Procedure: - If excess friction wear is present, repair the fan drive with the appropriate Horton repair kit or remanufactured or new fan drive. - If over-cycling of an on/off fan drive is resulting in excessive friction wear, a Horton DM Advantage ® Two-Speed or PolarForce ® Two-Speed Conversion Kit should be considered to replace an on/off fan drive when making the repair. Inspection Procedures FMFD IRON PULLEY ALUMINUM SPRING HOUSING FRICTION LINER MEASURE THIS DISTANCE TO DETERMINE WEAR and On/Off and Two-Speed Fan Drives and Horton Fans NOTE: All Inspection Procedures to be conducted with the engine off. Recommended 25,000-mile (40,000 Km) or 300-hour Preventive Maintenance (whichever comes first). Check area between pulley and clutch pack for air leaks Check bleed hole for air leaks Check for discoloration or other signs of overheating Inspect friction liner wear Signs of overheating CATALOG NUMBER 18 www.midwestwheel.com NLINE www.midwestwheel.com Order NLINE ™