The Mazda B-Series is a line of pickup trucks manufactured by Mazda Motor Corporation from 1961 to 2006. The number in the series indicates the displacement of the engine, so a Mazda B-4000 has a 4-liter engine. This engine utilizes electronic fuel injection, which requires a highly pressurized fuel system. The fuel pump in a Mazda 4000 is mounted to the fuel tank, so the tank must be removed to service the pump.
Open the cap on the fuel tank to relieve pressure. Connect pressure gauge T80L-9974-B to the pressure relief valve on the fuel supply manifold. Place the open end of the bleed hose on the pressure gauge into a gasoline container. Open the pressure gauge to relieve the pressure in the fuel system. Disconnect the pressure gauge from the pressure relief valve.
Disconnect the cable from the battery's negative terminal to prevent accidental sparking. Siphon as much fuel as possible with a hose from the fuel tank into a gasoline container. Raise the vehicle with a jack and mount it on jack stands. Remove the mounting bolts for the skid plate with a socket wrench and remove the skid plate.
Detach the fuel lines from the fuel tank and disconnect the electrical connections to the fuel pump. Support the fuel tank with a floor jack and remove the mounting bolts for the fuel tank straps with a socket wrench. Disconnect the fuel tank straps without deforming the fuel tank. Detach the fuel tank and lower it from the vehicle with a floor jack.
Clean the fuel tank around the fuel pump with a shop towel to prevent contamination of the fuel when you remove the fuel pump assembly. Turn the locking retainer ring for the fuel pump assembly with a socket wrench and locking ring adapter. Remove the locking retainer ring and pull the fuel pump assembly from the fuel tank without damaging the float arm or fuel filter. Discard the mounting gasket for the fuel pump assembly and clean the mounting surface for the fuel pump assembly.
Install the new fuel pump and mounting gasket by performing Steps 2 through 4 in reverse. Tighten the locking ring for the fuel pump assembly by turning it clockwise until it locks into place. Fill the tank with gasoline and check the fuel system for leaks.
