Tools:

• Razor Blade
• 1/4 inch sockets
• T25 Torx Wrench
• Flathead Screwdriver
• WD40 (or other lubricant)
• 1/2 inch Sockets

Parts:

• GM Part number 15131046 – fuel filler hose
  • Amazon for $25
  • Also find it at the junkyard on these vehicles (Credit to Jeep Forum):
    • 2003 Chevrolet TrailBlazer with 83 L (22 Gallon) Fuel Tank (RPO NNK)
    • 2003 GMC Envoy with 83 L (22 Gallon) Fuel Tank (RPO NNK)
    • 2003 Oldsmobile Bravada with 83 L (22 Gallon) Fuel Tank (RPO NNK)
    • 2002-2003 Chevrolet TrailBlazer EXT
    • 2002-2003 GMC Envoy XL
    • 2004 Buick Rainier
    • 2004 Chevrolet TrailBlazer, TrailBlazer EXT
    • 2004 GMC Envoy, Envoy XL, Envoy XUV
    • 2004 Oldsmobile Bravada

 

Take your razor blade and cut a little above where the flapper is located in the filler hose.

Cut down the tube until you have reached the other side of the flapper.
You should be able to remove the flapper from the hose.

Look under the quarter panel by the fuel cap. There is a piece of plastic that can easily be moved out of the way to reveal the filler hose underneath. Excuse the dirty Wrangler.

The hose is held on by two hose clamps. The one attached to the gas tank is oriented poorly and a pain to remove but not terrible. The upper one is simple but the hose is likely harder to remove from the metal filler neck than the lower plastic tank attachment.

Once both the clamps are loosened sufficiently I removed the breather hose as well.

Remove the upper metal fuel filler neck from the body by unscrewing the 4 torx screws.

Now with a bit of muscle you can remove the whole filler tube assembly from the Wrangler.

Once you have removed the assembly you can separate the hose from the fuel filler neck using a flat head screwdriver to loosen it up a bit.

At this point you need to think about how you are going to position the flapper in the hose. You will want to position it with the flapper on top and so the pivot point is at the highest point of the flapper assembly in the tube. You can see in the picture how I will position it in the tube.

Now it is time to insert the flapper into the hose. It really goes in quite easily unless you are trying to do this in the freezing cold. I liberally sprayed some WD40 in there to lubricate it. Once lubricated you can insert the flapper from the top of the hose and push it down inside with a similarly sized socket and extension. Be sure to position it correctly at this point. If you put it in backwards you will not be able to put fuel into your Wrangler. If the flapper pivot is not positioned on the high point of the hose it may cause you problems as well.

I pushed it almost to where it starts to curve. You can push it further if you want but it is not needed. Once you have jammed it in there sufficiently you can pull out the socket and get ready to install it back on your Jeep Wrangler.

To make the tank-side clamp easier to tighten you can release the tab that holds it on the hose with a flat head screwdriver and rotate it about 90 degrees or a fourth of the way as pictured. You can then pinch the tab back down to hold the clamp in place for installation.

Attach the hose back on the metal fuel filler neck without tightening the clamp. Also, attach the hose to the tank and position the hose so everything can be tightened.

Tighten everything back up and attach the breather hose. Also, if your axle breather valve was zip tied up there, be sure to put that back too.

Now you are good to go. No more gas overflowing at the pump. This is one of the most satisfying fixes you will do.