GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C6/C7/C8 🢒 Engine 🢒 Engine Controls - 7.2L (Caterpillar) 🢒 Fuel Tank Replacement

Removal Procedure
  1. Drain the fuel from the tank. Refer to Fuel Tank Draining .
  2. If equipped with an air tank , loosen the air tank clamp nuts and position the air tank to gain access to the fuel tank supports.
  3. Support the fuel tank .

    4. Object Number: 816451 Size: SH
  4. Remove the fuel tank support nuts .

    5. Object Number: 816417 Size: SH

    Important: The fuel lines are not designed to uncoil and flex to provide added ease of removal. It may be necessary to remove the tape around the fuel line coil to gain more access.

  5. Lower the fuel tank enough to disconnect the fuel lines and electrical connector.

    6. Object Number: 724691 Size: SH
  6. Disconnect the fuel and evaporative emission (EVAP) lines. Refer to Metal Collar Quick Connect Fitting Service in Engine Controls - 7.8L.
  7. Disconnect the fuel sender assembly electrical connector.
  8. Remove the fuel tank with the fuel tank supports from the frame rail.
  9. Remove the fuel feed and return the line coils (1, 3) from the sending unit (2). Refer to Metal Collar Quick Connect Fitting Service in Engine Controls - 7.8L.
  10. Remove the fuel sender assembly if replacing or servicing the tank. Refer to Fuel Sender Assembly Replacement in Engine Controls - 7.8L.
  11. Remove the fuel tank steps. Refer to Step Replacement in Body Front End.
  12. Remove the nuts, washers, and both fuel tank straps and supports from the fuel tank.
  13. Remove the nut and the fuel sender assembly ground lead from the fuel tank. Note the position of ground lead for installation.
  14. Remove the fuel cap chain retainer and the fuel cap if the fuel tank is being replaced.
  15. Purge the tank if the tank is being serviced. Refer to Fuel System Cleaning .

Installation Procedure
  1. Install the fuel sender assembly if replacing or servicing the tank. Refer to Fuel Sender Assembly Replacement in Engine Controls - 7.8L.

    2. Notice: Refer to Fastener Notice in the Preface section.

  2. Install the fuel tank ground lead.

    3. Tighten
    Tighten the nut to 9 N·m (7 lb ft).

  3. Install the fuel feed and return the line coils (1, 3) from the sending unit (2). Refer to Metal Collar Quick Connect Fitting Service in Engine Controls - 7.8L.
  4. Install the fuel tank chain to the fuel tank with the retainer, if removed.
  5. Install the fuel tank onto the fuel tank supports with the strap to the fuel tank supports.
  6. Install the fuel tank strap nuts and the washers .

    7. Tighten
    Tighten the nuts to 175 N·m (129 lb ft).

  7. Reconnect the fuel sender assembly electrical connector.

    8. Object Number: 724691 Size: SH
  8. Install the fuel feed, fuel return , and EVAP lines to the fuel sender assembly . Refer to Metal Collar Quick Connect Fitting Service in Engine Controls - 7.8L.
  9. If the fuel line tape was removed, tape the fuel line coil.

    10. Object Number: 816450 Size: SH
  10. Install the fuel tank supports to the frame with 2 anchor plates and 6 nuts.

    11. Tighten
    Tighten nuts to 175 N·m (129 lb ft).

  11. Slide the fuel tank into position and support the fuel tank.
  12. Install the fuel tank steps. Refer to Step Replacement in Body Front End.
  13. If equipped with an air tank, reposition the air tank and tighten the air tank clamp nuts.

    14. Tighten
    Tighten the primary air brake supply reservoir support strap nuts to 13 N·m (115 lb in).

  14. Refill the fuel tank.
  15. Inspect for leaks.