OM4033.2 Maintenance - Section 4 Automatic Lubrication System 4-23 SYSTEM TROUBLESHOOTING CHART I f the following procedures do not correct the problem, contact a factory authorized service center. TROUBLE POSSIBLE CAUSES SUGGESTED CORRECTIVE ACTION Pump Does Not Operate Lube system not grounded. Electrical power loss. Timer malfunction. Solenoid valve malfunctioning. Relay malfunctioning Motor or pump malfunction. Correct grounding connections to pump assembly and truck chassis. Locate cause of power loss and repair. 24 VDC power required. Be sure keyswitch is “ON”. Replace timer assembly Replace the solenoid valve assembly Replace relay Repair or replace motor and/or pump assembly.
(Refer to Service Manual for rebuild instructions.) NOTE: On initial startup of the lube system, the timing capacitor will not contain a charge, therefore the first timing cycle will be about double in length compared to the normal interval. Subsequent timer cycles should be as specified. Pump Will Not Prime Low lubricant supply. Dirt in reservoir, pump inlet clogged, filter clogged. Pump Will Not Build Pres- sure Air trapped in lubricant supply line. Lubricant supply line leaking. Vent valve leaking. Pump worn or scored. Prime system to remove trapped air. Check lines and connections to repair leakage. Clean or replace vent valve. Repair or replace pump assembly.
(Refer to Service Manual for rebuild instructions.) Injector Indicator Stem Does Not Operate NOTE: Normally, during operation, the injector indicator stem will move into the body of the injector when pressure builds properly. When the system vents (pres- sure release) the indicator stem will again move out into the adjusting yoke. Malfunctioning injector - usually indicated by the pump building pressure and then venting. All injectors inoperative - pump build up not sufficient to cycle injec- tors. Replace individual injector assembly. Service and/or replace pump assembly.
(Refer to Service Manual for rebuild instructions.) Pressure Gauge Does Not Register Pressure No system pressure to the pump motor. No 24 VDC signal at pump sole- noid. Pressure reducing valve set too low. 24V Relay (RB6, K6) may be defec- tive. Check hydraulic hose from steering sys- tem. Determine problem in 24 VDC electric system. Refer to “Pressure Control Valve Adjust- ment”. Replace relay.