SERVICE MANUALROBERT BOSCH MODEL MW INJECTION PUMPSection 11TIGHTENING UNSEALED NUTS OR SCREWS TOCORRECT LEAKAGEUnsealed nuts or screws may be tightened to stop fuel orlubricating oil leakage. When careful tightening does notstop leakage, fittings which use copper gaskets can beremoved. For example, injection pump housing fuel inletand outlet fittings and oil inlet fitting use copper gasketsbetween fitting and housing which can be replaced.IF DELIVERY VALVE HOLDER (FIGURE 27) LEAKS,DO NOT TIGHTEN HOLDER. FOLLOWPROCEDURES IN CURRENT WARRANTY MANUALTO RESOLVE HOLDER LEAKAGE.Figure 27.REPAIRING OR REPLACING FUEL INLET ORRETURN FITTINGSReplacing Fuel Return Check Valve The fuel returncheck valve (Figure 28) has a nominal opening pressureof 18 psi and retains fuel within injection pump whenengine is stopped. Return fuel flow from pump iscontrolled by an orifice in the fuel return hose.The valve can be cleaned or replaced as required. Toremove valve, disconnect fuel return hose at fuel returnline fitting located just below intake manifold center.Noting position of valve will aid in its reinstallation.Figure 28.Injection Pump Housing Pump Return Connectorand ElbowFuel leakage can occur at injection pump housing returnelbow or connector (Figure 28). If tightening does notstop leakage, install new elbow fitting or use LoctiteHydraulic sealant on elbow. Install a new copper gasketif fuel leaks at pump housing connector.Injection Pump Housing Inlet Connector and ElbowThe final filter to pump housing hose (Figure 29) uses aflex connector at the filter header. Remove hose atheader, then hose bracket at bottom of pump housingprior to removing hose. The hose connects to a brasselbow which is threaded into the pump housingconnector (Figure 29). Fuel leaks may be corrected byinstalling a new copper gasket between pump housingand inlet connector or by installing a new elbow.CGES-185-3PRINTED IN UNITED STATES OF AMERICAPage 21
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
