Hummer H1 (2006+). Manual - part 174

3-38 Fuel, Emissions, and Exhaust

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Auxiliary Fuel Tank Vent Filter 

The auxiliary fuel tank vent filter is tie strapped to the top of the auxiliary fuel filler neck hose.

The filter is serviced as an assembly and should be replaced if restricted or damaged.

Removal

1.

Remove and discard the tie straps securing the vent hose to the fuel filler neck hose.

2.

Disconnect the clamp from the filter’s vent line.

3.

Remove the filter from the vent line

Installation

1.

Install the filter on to the vent line.

2.

Install the vent line clamp.

3.

Secure the vent line to the fuel filler neck with new tie straps.

Main or Auxiliary Tank Fuel Line Replacement (All)

Removal

1.

Drain the fuel tank.

2.

Remove the main or auxiliary fuel tank as described in this section.

3.

Disconnect any electrical wires, linkage parts, cables, or lines as needed if insufficient slack exists.

4.

Disconnect the fuel lines at the tank tubes.

5.

Remove the line clamps and the tie straps.

6.

Disconnect the lines at the fuel tank selector valve and remove the lines.

7.

Remove the supply and/or the return lines as needed (Figure 3-19).

Installation

1.

Route the new lines as needed (Figure 3-19). Be sure the lines are not kinked, pinched, or touching hot or rotating parts.

2.

Secure the lines to the frame with clamps, brackets, P-clips, and tie straps as needed.

3.

Connect the rear lines to the auxiliary or main tank as required.

4.

Install the main or the auxiliary fuel tank as described in this section.

5.

Verify that the fuel lines are securely connected and properly routed.

6.

Refill the fuel tank.

7.

Check the tank operation. Verify the proper transmitter operation and selector switch function.

Fuel Tank-To-Filler Neck Hose Replacement

Removal

1.

Drain the fuel tank.

2.

Remove the filler tube housing bolts.

3.

Disconnect the filler tube vent hose.

4.

Loosen the clamps and remove the hose from the tank and filler (Figure 3-23).

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 Fuel, Emissions, and Exhaust  3-39

Figure 3-23:   Filler Tube-To-Tank Attachment

Installation

1.

Install the hose on the tank and the filler tube and tighten the hose clamps.

2.

Install the filler tube and housing.

3.

Fill the fuel tank and check for leaks.

Fuel Tank Draining 

The fuel tank should only be drained with portable air powered drain equipment. This type of equipment is OSHA approved and
will drain the tank through the filler neck.

The tank should be drained prior to removal. Follow the drain equipment manufacturer’s instructions explicitly.

Main Fuel Tank

The main fuel tank is constructed of Polyethylene (Figure 3-24). It is mounted by two straps on the body, inside the right frame
rail. An expandable-type drain plug is provided at the bottom of the fuel tank. The fuel tank top cover is accessible only by removal
of the fuel tank from the vehicle. With the fuel tank removed, the fuel tank sending unit, fuel strainer and fuel supply tube may be
serviced.

Figure 3-24:   Fuel Tank

Removal

1.

Drain the tank with the recommended equipment.

2.

Remove the bolts attaching the fuel filler housing to the body.

3.

Disconnect the tank vent lines, and hoses at the branch tee in the fuel filler housing.

FILLER TUBE

TANK

FILLER TUBE

-TO-

TANK HOSE

 INLET 

TUBE

3-40 Fuel, Emissions, and Exhaust

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4.

Remove the clamps attaching the filler tube to the vent line or body.

5.

Disconnect the filler housing ground strap.

6.

Loosen the clamps securing the connecting hose to the filler tube and the housing (Figure 3-25).

Figure 3-25:   Filler Tube-to-Tank Attachment

7.

Remove the fuel filler housing and the filler neck.

8.

Raise the vehicle.

9.

Remove the rear propeller shaft.

10. Remove the transfer case rear extension housing (Refer to section 5).

11. Rotate the rear axle yoke to a vertical position. The tank may not clear the yoke otherwise.

12. Support the tank with a transmission jack or a other suitable support device.

13. Remove the bolts and nuts attaching the front and rear upper straps to the lower straps (Figure 3-26).

Figure 3-26:   Fuel Tank Mounting Strap Attachment

14. Disconnect the vent lines at the fuel tank.

15. Lower the tank enough to gain access to transmitter wires and the fuel lines.

16. Disconnect the transmitter wires.

17. Disconnect but do not remove the rollover valve line.

18. Lower and remove the fuel tank.

Installation

1.

Position the tank on a jack and raise the tank just enough to permit installation of the wires and lines. 

2.

Connect the fuel lines as follows:

a.

Push the lines onto the tank supply and return tubes. Note that the fuel supply tube is larger in diameter than the return
tube.

b.

Push the line onto the tank tube until it snaps or clicks into place. 

FILLER TUBE

CLAMP

HOUSING

STRAP

UPPER

LOWER STRAP

FUEL TANK

SUPPORT STRAP

LOWER

STRAP

 STRAP

 BRACKET

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 Fuel, Emissions, and Exhaust  3-41

c.

Pull on the lines to verify that there is a secure attachment. 

3.

Connect the wiring and vent lines. Also connect the rollover valve line. 

4.

Install the filler neck-to-tank hose on the fuel tank. Secure the hose with new clamp if required. 

5.

Position the tank and install the bolts and nuts that attach the tank upper to the lower retaining straps. Tighten the strap bolts to
23-27 lb.-in. (3 N•m) torque. 

NOTE:

If the upper and lower straps touch after bolt tightening, replace the straps. They are stretched and will not adequately secure the

tank. 

6.

Install the transfer case rear extension housing.

7.

Install the propeller shaft.

8.

Connect the tank vent lines. 

9.

Lower the vehicle

10. Install the filler neck and connect the ground strap. 

11. Install the filler neck housing and connect the vent line. 

12. Refill the tank. 

13. Start the engine and verify proper operation. Repair any leaks if necessary. 

Fuel Level Transmitter/ Access Plate Replacement

The fuel level transmitter, vents, and access plate can all be serviced once the tank is out of the vehicle (Figure 3-27). 

If the fuel tank requires replacement, be sure to replace all necessary gaskets, O-rings, seals, and strainer with new parts. Coat
fitting threads with Loctite PST before installation. 

Tank Cleaning

In cases where the tank was removed for correction of contamination, remove the transmitter and access plate for maximum access.
Use a soap and water solution and low pressure steam gun. Be sure to clean out the fuel supply and return lines as well. The tank
can be dried with compressed air or allowed to air dry as desired.