GM Full-Size Trucks 1980-1987 Repair Guide

Fuel Supply Pump


The fuel supply pump on 350 (5.7L) diesel engines is a single action diaphragm type and is serviced by replacement only. No adjustments or repairs are possible. The pump is operated by a pushrod between the camshaft eccentric and the fuel pump which operates the pump rocker arm.


Before removing the fuel pump allow the engine to cool completely to prevent ignition and possible fire from hot engine components such as the exhaust manifold.

When you connect the fuel pump outlet fitting, always use two wrenches to avoid damaging the pump.

  1. Disconnect the fuel intake and outlet lines at the pump and plug the pump intake line.

Keep a rag handy to soak up any fuel that might spill on any other components. Immediately dispose of the rag in a container approved for flammable or combustible refuse.

  1. Remove the upper bolt from the right front mounting boss. Insert a long bolt ( 3 /8 in.-16 x 2 in.) in this hole to hold the fuel pump pushrod.
  3. Remove the two pump mounting bolts and lockwashers; remove the pump and its gasket.
  5. If the rocker arm pushrod is to be removed, remove the two adapter bolts and lockwashers and remove the adapter and its gasket.
  7. Install the fuel pump with a new gasket reversing the removal procedure. Coat the mating surfaces with sealer.
  9. Connect the fuel lines and check for leaks.