Just like everything else on this Earth, time and the elements will continue to wear until there is nothing left. One of the more susceptible areas of your Subaru to the winds of time is the fuel filler neck. Pulling off it’s plastic battle armor (if you live in a harsh winter environment) will show you a well worn soldier. It has tried it’s best but once the rust takes hold it is only a matter of time.

With newer Subaru’s being drive by wire once emission leaks start from this area your cruise control is doomed to be offline. But with a little time, effort and know how you can alleviate this problem, let’s take a look at what it takes.

Time frame

This is a pretty straightforward job that should be done in less than an hour and half. -Unless- rust has taken hold, do a quick removal of the plastic shield before delving into this repair to save yourself from additional headaches. Having your gas tank as low as you can is also a big plus, the more fuel the more fumes and the likelihood of spills.

Tools

This list is pretty simple with just a few nuts, bolts and clamps holding it altogether. Find you favorite socket set with a ratchet, a flathead screwdriver, a couple pliers of various sizes and lastly a decent sized prybar can help you remove the rubber hose and filler neck.

Grey Pneumatic 3/8th socket set Gearwrench 3/8ths ratchetMilwaukee 3/8ths electric ratchet Milwaukee 3/8ths impact gun — Grey Pneumatic 3/8th socket set Gearwrench 3/8ths ratchet
Milwaukee 3/8ths electric ratchet Milwaukee 3/8ths impact gun

Parts

As stated in the title we will need a new fuel neck. I sourced mine from Subaru but there are plenty of aftermarket options out there. Other parts that are likely worn, torn and ready for replacement are the fuel neck valve and rubber gasket.

Other common items are the hardline that runs along the fuel neck and the rubber hoses.

Do not proceed:

If your work area is unventilated, fuel fumes are no joke and can/will cause serious health hazards. Even in a well ventilated area I would highly recommend a respirator mask with the proper filtration.

Highly Recommended:

Before starting this job run the tank as low as you can. Anything under 1/4th a tank will help keep gas spillage and fumes ruining your install and giving you a mess and massive headache.

How to

You can start with finding a flat area to proper chalk your car and lift it skyward. If you need help lifting your Subaru click this link to follow along. You will likely only need to lift the rear up to get all the access you need.

Getting the vehicle off the ground, with the passenger rear wheel removed and on jack stands will help open up your work area.

Next up removal of the right rear passenger tire will help you open up your work area. With the plastic shroud visible you can now unbolt the three bolts that hold it in. There is very likely that these bolts will break off, so be ready for it. Having the shield out of the way you can now see the rusty mess that is your filler neck.

Here were are looking at the filler neck. I had previously removed the cover while investigating a emissions code.

With the fuel door open we can start with the gas cap, stuffing a few rags down in it will keep the fumes to a minimum. Now the three bolts that surround the fuel neck will need to be removed. This allows you to take out upper plate that sandwiches the fuel neck to the unibody.

We can head down into the wheel well to undo various emissions hoses. If you haven’t purchased replacement hoses for these you will want to take the upmost care. These lines will be very fragile and a hard twist with a pair of pliers can tear them. There are two located just to the right of the filler neck. The last one will reside on the underside of the car below the fuel neck.

You can now set your sights on the rubber fuel hose that the filler neck slides into. With the clamp loosened you will want to take a dull flathead screwdriver to help break the rubber hose’s seal on the neck, by following around the outside of the filler neck. Using a can of rust penetrant you can spray in between the rubber hose and filler neck. Slow and steady is the name of the game, unless you would like to replace it. When you the seal is broken between the two items you can begin to pull the neck away from the tube.

Pop! Freedom! If you find the filler neck not coming free, put a prybar on subframe above the filler neck and push the filler neck away from the rubber hose.

If you find issues with them separating by hand, I found placing a pry bar against the subframe and pushing the filler neck to the rear of the car can help pop the filler neck free. You have now freed your filler neck!

Here is the rusty mess of a fuel filler neck! Some areas looking much better than others.

Up next you can start removing the rubber hoses and hardline to transfer them over. As stated in the parts section I highly recommend having replacement parts ready to go incase of a line or hose breaking. The check valve on the backside of the filler neck was so rusty it was unable to be removed and new nuts were necessary.

Swapping over the hardline and hoes to the new unit.

After you have swapped over all your hoses, hardlines and valve it’s time to install the new unit! I highly recommend placing the filler neck into the unibody opening. Then moving back down below the car to slide the neck into the rubber tank hose. You can use a small spray of rust penetrant to help if the neck won’t slide in. Then sliding the clamp into place you can tighten it down.

This is where the new rubber seal goes to protect the painted side of the car.

Then the upper metal plate goes on top and you reinstall your bolts.

We can move to the hardlines on the unibody and connect the two hoses and clamps to complete the evaporative lines. Then moving to the fuel filler door you can place your new seal and the upper plate that sandwiches everything together. Installing the final three bolts will secure the neck to the car. Lastly you can take your plastic splash shield and reinstalling it to the filler neck to help keep the new unit from rusting out even faster.

Congrats! You have now replaced your fuel filler neck and can continue to fill your vehicle the favorite fossil fuel of your choice! If your fuel neck was rusted through you may have repaired a check engine light and an evaporative emissions leak.