Usage:
3406B (PEEC) Truck Engines (8TC)
Description of Change: The magnet on the end of the rack assembly in the fuel injection pump group has been improved. See Illustration 1. The epoxy in the former magnet could soften and flow from around the magnet. See Illustration 2. This could cause the rack sensor to loose contact with the rack which causes a Fault Code 22 (rack position fault). The improved magnet contains a different epoxy (red in color instead of the former black). The red epoxy will not soften and flow out of position.
Illustration 1. Location of the 7W7819 Magnet in the 4W3942 Fuel Injection Pump Group.
Illustration 2. Cross section of 7W7819 Magnet.
Adaptable To:
The improved 7W7819 Magnet is part of the 4W2618 Regulator Rack Assembly in the 4W3942 Fuel Injection Pump Group used on 3406B (PEEC) Truck Engines. The part number of the improved magnet has not changed.
Caterpillar recommends replacing the former magnet (with the black epoxy) with an improved magnet (with red epoxy) whenever repairs are needed. The threaded shaft of the magnet is 2.1 mm (.08 ") in diameter. Use care not to break the shaft when removing or installing the magnet on the end of the rack.