GM Full-Size Trucks 1980-1987 Repair Guide

Gasoline Fuel Filter

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CAUTION
To reduce the chance of personal injury, cover the fuel line with cloth to collect the fuel and then place the cloth in an approved container.

There are three types of fuel filters; internal (in the carburetor fitting), in-line (in the fuel line) and in-tank (the sock on the fuel pickup tube).

REMOVAL & INSTALLATION




CAUTION
Before removing any component of the fuel system, refer to the Fuel Pressure Release procedures in this section and release the fuel pressure.

Carbureted Engines

Internal filters are located in the inlet fitting on all carburetors. Elements are placed in the inlet hole with the gasket surface outward. A spring holds the element outward, sealing it by compressing a gasket surface against the inlet fitting. A check valve is also built into the filter element.

  1. Make sure the ignition is off.
  2.  
  3. Relieve fuel system pressure by unscrewing the fuel tank cap.
  4.  

See Figures 1, 2, 3 and 4

Click image to see an enlarged view

Fig. Fig. 1: Use a suitable line wrench to disconnect the fuel line from the carburetor fuel inlet nut

  1. Disconnect fuel line connection at fuel inlet filter nut.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Loosen the fuel inlet nut using the proper size line wrench or socket

  1. Remove fuel inlet filter nut from carburetor. Using a line wrench will prevent the flats on the nut from rounding during removal and tightening.
  2.  



Click image to see an enlarged view

Fig. Fig. 3: Finish unthreading the fuel inlet nut by hand, then remove the nut and fuel filter assembly from the carburetor

  1. Remove filter and spring.
  2.  



Click image to see an enlarged view

Fig. Fig. 4: The fuel filter may now be remove from the inlet nut

  1. If removed, install check valve in fuel inlet filter. The fuel inlet check valve must be installed in the filter to meet Motor Vehicle Safety Standards (MVSS) for roll-over. New service replacement filters must include the check valve.
  2.  
  3. Install fuel inlet filter spring, filter, and check valve assembly in carburetor. Check that the valve end of filter faces toward the fuel line. Ribs on closed end of filter element prevent filter from being installed incorrectly unless forced.
  4.  
  5. Install nut in carburetor. Tighten nut to 18 ft. lbs. (24 Nm).
  6.  
  7. Install fuel line and tighten connection.
  8.  
  9. Start engine and check for leaks.
  10.  

Gasoline Fuel Injected Engines

The 220 TBI unit used on the V6 and V8 engines contains a constant bleed feature in the pressure regulator that relieves pressure any time the engine is turned off. Therefore, no special relieve procedure is required. However, a small amount of fuel may be released when the fuel line is disconnected.

The in-line filter on the fuel injected models is found along the frame rail.

  1. Make sure the ignition is off.
  2.  
  3. Disconnect the fuel lines.
  4.  
  5. Remove the fuel filter from the retainer or mounting bolt.
  6.  
  7. To install, reverse the removal procedures. Start the engine and check for leaks.
  8.  

The filter has an arrow (fuel flow direction) on the side of the case, be sure to install it correctly in the system, with the arrow facing away from the fuel tank.

 
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