PLUG 3711281 - Caterpillar

Illustration 1 g00608423
(1) Screen (if equipped) (2) Check valve (3) Spring (4) Bolt (5) Expansion plug (6) Passage (7) Piston assembly (8) Cam (9) Tappet (10) Sleeve assembly (11) O-ring seal
Inspect expansion plug (5) for leaking fuel. If the expansion plug is faulty, replace the fuel transfer pump. Refer to the Governor Service Manual, SENR6454.
Disconnect the inlet fuel line to the fuel transfer pump and check screen (1) (if equipped) for plugging.
Disconnect outlet fuel line for the fuel transfer pump.
Remove check valves (2). Ensure that the orientation of both check valves agrees with the illustration. Install new check valves if the sealing surfaces are rough, worn, or embedded with debris.
Sudden release of spring force can cause injury.To prevent the possibility of injury, follow the procedure to relieve the spring pressure.
There is a spring force behind the cover for the fuel transfer pump. When the bolts that hold the cover in position are removed, the spring force will be released. To prevent possible personal injury, hold the cover in position as the bolts are removed. Remove the cover for the fuel transfer pump by removing three bolts (4). Hold the cover in position and slowly remove the bolts.
Remove piston assembly (7) and sleeve assembly (10). A spring and a check valve are part of the piston assembly. Tappet (9) is part of the sleeve assembly. Inspect the tappet for unusual wear. Replace the sleeve assembly if the tappet shows unusual wear. Inspect the piston and the sleeve assembly. It is normal for the surface of the piston to be polished. Replace the piston and/or the sleeve assembly if excessive wear or deep scratches are present.Note: A shiny, circular wear pattern is normal.
Reassemble the governor components. Use two new O-rings (11) when the sleeve assembly is reinstalled.