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How To Replace Fuel Tank Filler Neck 02-07 Subaru WRX

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Hi. I'm Mike from 1A Auto. We've been installing auto parts for over 30 years.

We'll follow our instructions on our scan tool. This vehicle has a Check Engine light on. Change that.

So it's a PO457, so you'd have a control system. It's a small leak, so it says a leak cap loose/off. It's telling me that the gas cap may need to be replaced. It has been replaced on this car, and the code came back. So we believe that the filler neck is rusty and rotted, because this car has lived its entire life in the Rust Belt. So we're going to replace the filler neck to solve our problem.

To remove this patch of side kick panel, you'd have the door open. There's a small plastic clip here. I'm gonna use the plastic prying tool, you can get these from, just kind of slide it underneath here, and gently pry it out. Try not to pop it out, and then lose it.

So once it pops out, there's a white gromit that locks it, and pushes in there, so that can be reused. Put that aside. There's another fastener here, it's a plastic fastener, so you can actually, if it's too tight, you could use a flatblade screwdriver or the flat end of your trim clip tool and turn it. It's pretty loose, and I'm actually gonna turn it with my fingers to unscrew it. And then pull it off.

I'll take the plastic prying tool, we'll go up underneath this plastic. Just go along, and pop it up off the clips. Pull out the trim.

So with the trim out of the way, we can reach up and up here next to this brown connector on the other side is a green connector. Unplug that green connector, and that's the fuel pump relay. With that unplugged, we can start up the car and let it stall. It will release the fuel pressure, and you can work on the fuel system of the car.

So when you're working on any part of the fuel system in the car, you wanna relieve the fuel pressure. So say you wanna disconnect the fuel line, change the fuel filter. This way you don't have fuel spraying out on you when you go to release those lines. This is the easier way to release that pressure, it makes less of a mess. Basically disconnect it, the fuel pump doesn't run, and you could start the car on the fuel pressure that's remaining in the lines. That fuel runs out, the car stalls, you shut it off, and the fuel pressure is released from the lines.

We're gonna reach up and push the lock in, it's this green tab. Unplug it. Just like that. Leave it unplugged, and now I can start the car. There we go. That's all it takes.

Once it stalls, try to start it a couple times more. A little bit of fuel pressure left. That should be good.

Loosen the lug nuts of the vehicle on the ground. This one has special lug nuts, so I'm gonna use the key. The stock lug nut size is 19 millimeter. This one uses a 21, but it'd be the same exact operation. You use the breaker bar with your 19 millimeter socket, and you just break the lug nuts loose one at a time.

Raise and support the vehicle. You can use a jack and jack stands. We're gonna use our two post lift.

Just use your socket, or in this case the lug nut tool. Finish removing the lug nuts by hand. Take the wheel entire off and put it aside.

To replace the filler neck, you wanna make sure that your fuel tank is at a quarter or less; otherwise you'll need to drain some fuel from the car. It's easiest just to drive it if you can, and run the fuel tank down. You don't want it filled to the top, because when you release this filler neck, you'll spill some gas.

The other thing to note too is that since you're working with gas, there's gonna be gas fumes. Make sure you're working in a well ventilated area, no open flames, sparks, whatever. Just be careful replacing this filler neck.

With that being said, we're gonna remove this cover to get to it. There is a 10 millimeter bolt here, a 10 millimeter bolt here, and then a 10 millimeter nut here on a stud. I've tried to spray them with some rust penetrant. I'm gonna spray some more, they're pretty rusty. It's likely that they're gonna break, so you may wanna have some of these on hand.

Spray some rust penetrant on this stud down here. And we'll try to spray some in here. And try to spray some up here. This cover to protect the filler neck kind of prevents me from getting to the back of them.

I'm gonna use a 10 millimeter socket extension and a ratchet. Gonna go on this one down here, on the stud. Try to get this to move. Yeah, it's just ... it's so rusted. It broke right off.

Try this bolt here. Yup, that one broke. And this one's probably gonna break too. This car's lived its whole life in the Rust Belt. And it's likely this filler neck is very rusted. Yes, it's all rusted here, and up here.

Lemme go up behind, there's three bolts that secure the filler neck to the body. I'm gonna spray the backside of these bolts, that way I can get to them. Back here. Mostly gonna spray this one, 'cause I can get to it now. Remove the gas cap. Let that hang.

There are three eight millimeter bolts that are holding in this flange that's holding in the filler neck up in the body. That one's coming free. Collar can come out.

At this point, I would take a picture of your filler neck and just make sure that you can see all the lines, because you're gonna disconnect a couple of the lines here, and you just wanna make sure you get them back in the same spot. So it's a good idea to just take a picture of it to help you remember. Take those pliers. We'll squeeze these spring clamps and just slide them up the hose. Same for both. Now use a right angle pick to try to break the seal on the hose, but not try to damage the hose too much. So just kind of work around like that. And then you can pull the hose up. These lines are in good shape. I'm gonna try to save these lines. Our replacement filler neck does come with them, from 1A Auto. But since they're in good shape, I kind of wanna leave them in place. Pop this line off.

This one can stay together here. If you follow it down underneath, there's a connector spring clamp here that'll disconnect and pop this one off. We're gonna get to this spring clamp here, see? It's a little bit rustier. For now, lemme slide this off. Like that. Take a right angled pick underneath the hose. Guide the hose off like that.

This is a 10 millimeter bolt behind here. It's pretty rusty, so I gotta force the socket on there. I sprayed some rust penetrant on there, and just gonna work it off. If it comes off a little hard, I can go to it once to stop.

Spray some more rust penetrant on it. And then turn it back on, and continue that process to work rust penetrant into the threads. That's tightening it, now we'll loosen it. It's starting to come loose. So just kept working rust penetrant in here, back and forth, just trying to get the rusty bolt out. Now it's free. So we'll leave that loose. Filler neck will come off of here, once I loosen it from the bottom.

Gonna loosen this hose clamp. It's really, really rusty. I actually knocked some of the rust off of it. Not quite a actual size anymore. Worst case, if you need to you could very carefully clip this off. I'm gonna try to jam a nine millimeter on here, a socket, and see if I can get it to turn. We're gonna get lucky today, it's gonna turn and come off. I will replace this clamp with a new one, so you wanna have a new hose clamp on hand. I'm just gonna undo it as far as it'll go, and then bring it down and slide it over the filler neck here.

There's a push clip so that the filler neck is clipped to these lines here. It's a little bit rusty, I'm gonna spray some rust penetrant on it just to help it slide apart. And then I will take a small flat bladed screwdriver. There's a tab here, I'll push it in. Push this little tab in. And then on this side, I'll just try to push this up through like that. Okay. Filler neck is almost loose.

I'm gonna work on separating the filler neck from the hose on the end of the tank. Use a right angle pick, just kind of work around the hose. Try to break the seal.

I'm actually gonna use a older plastic prying tool. You can get these from 1A Auto. Just so I don't damage the hose, and gently help pry it around here. I just have to break the seal, the hose kind of rusted to it a little bit. And now I can work it out of here. There it is. I'm pulling the filler neck out. Got it out. Past the sway bar. Now you're really gonna smell the gas.

Here's the old filler neck pulled from the vehicle. Here's a brand new one from Does come with these extra breather hoses. They're actually mounted incorrectly, but it's just for shipping. So if you were to use these, the ones that are in the car are stainless and they're not rusty, so I'm not gonna use the ones that came with this. But if you needed them, they are here. You can take a 10 millimeter, and we'll just take them off. They should be pretty loose. And it's purely because of the way they're shipped. They don't have a threaded bolt hole to hold them to the filler neck. So when you're doing this and it looks like it doesn't fit or it's the wrong one, it's actually because these are just mounted here for shipping. So once you take this bolt out, they'd go in and get mounted to the car, and then they'd sit like this, just like the originals. And you'd reuse the bolt that you took outta here, and then this little tab doesn't get used for anything.

We're gonna use the filler neck like this. I need to swap over a couple pieces from it. These hoses can be reused. They're in pretty good shape. It doesn't look like it, but they're actually in pretty good shape, so we're gonna reuse them, and put this new one back in the car. And you just swap over this fuel shutoff valve, but other than that it'll be ready to go.

We're gonna use this hose, so I'm gonna use some needle nose pliers. We'll release the spring clamp here. Pull it up. Use the small pick, just gently pry underneath here. And just work it around it.

Pop the hose off. So the hoses are loose. Flip it over. Spray some rust penetrant on these nuts, on the studs. One on each side. These are eight millimeter, so we'll use the eight millimeter socket and ratchet. Carefully remove them. This one free. Pull this valve off.

I'm just gonna take some rust penetrant on a rag, and just wipe it down, some of the rust off of it. The little rubber seal. So I'll reinstall this part. Push it down in place. We'll use these nuts.

Now we'll tighten them down. Don't go super tight, you don't wanna break off these studs. They're very small. Need to get that one snug. Need to get this one tightened down. I'll just go, once they get tight, just go a little bit more. Just like that. See this hose is already lining up where it was originally. Put it over it.

Put the needle nose pliers and reinstall the clamp. Right back in the same position. Use our needle nose pliers, let's squeeze this clamp, pull it down. Use the pick to separate it.

This car had an EVAP code for a small leak, PO457. It said replace the gas cap. The gas cap was replaced, the code kept coming back. So it's likely that one of these lines here probably has a very small pinhole in it from rust, or somewhere in this area, and it's causing a very small evaporative leak, when the system goes into test mode. So we've replaced the whole filler neck, because it's all rusty.

Reinstall this hose. Go right to the stop. Put the clamp over it. And this will get clamped in the car. Need to remove these Phillips head screws from this collar, or else the filler neck's not gonna fit into the body. This goes on the outside of the body, and then sandwiches the filler neck and holds it in place. So you can just use a Phillips head screwdriver, there's also a slot cut in them for a flathead screwdriver. But I'll use the Phillips head. And we'll put that aside. Leave the rubber gasket on here, that'll go up against the body. Then when you put this in, goes down over it.

Put our new hose clamp on, so we don't forget to put that down first. That can sit like that. Then take a little bit of white grease, and just put it around here. That way it slides into the rubber hose that's going into the gas tank. And don't worry about it if the white grease gets into the gasoline, it will just dissolve. But this way it'll slide into the hose and not tear it.

So we're gonna go down. Get this lined up in place here. I'm gonna go underneath. Take this line out of the way. Put it up into the filler neck hose. Just like that. We'll move this, over like that. That will sit like that.

Install this hose clamp. You can see the line on the hose where it was, the original. Tighten this hose clamp up. Just a bit more. I'm using an eight millimeter socket, this way I can get it in place first, close to being tight. I'm gonna put it right back in the same place it was. There's a line marked on the hose. Hold it in place, and then tighten it.

This spring clamp looks pretty rusty, I'm gonna get rid of it. I don't think I wanna reuse it. Take it off this hose, get rid of it. I'm gonna put a worm clamp on here through the hose. Put it onto this one. Slide it down. Put that right about there. Flat blade screwdriver, just tighten it up. Let's open the metal part. Okay.

Push this plastic clip back in here. Lemme get this bolt caught here, and make sure you get this bracket here with the other lines in there. I just wanna get caught, I'm not gonna totally tighten it, 'cause I still need to mount the filler neck into the body, and I wanna have some movement on it. So I'll just get this caught. That should be good. Have some movement, I'll come back and tighten that afterwards.

I'll put this plate in. So it's obviously, it lines up with the shape that's there. And then the bolt holes will need to be lined up a little bit, I have to twist it just ever so slightly.

Alright, we'll put the screws in here. Might need to move the neck around. Get caught. Don't tighten it down all the way, wanna get the other ones caught.

Right. Bring them all down pretty evenly. You don't need to kill these. Till you feel them get tight, you can stop. We'll reinstall the gas cap. Done there for now.

Now I can tighten this bolt. Okay, and once you feel it get tight, just stop. Put these hoses back on. Take our needle nose pliers, clamps back down. Our filler neck was so rusted where it mounted the shield to the bottom, when I went to remove it, it broke off. So the nut's just spinning on the stud. Take some locking pliers. Try to grab onto this, so it doesn't spin. Let's see. Do my best to hold it.

And even if it breaks off, that's not a big deal. I'll find another nut to fit the new one. We're gonna reinstall the plastic protective shield. You just wanna make sure you put that back in there, 'cause it does protect it from rocks and debris. Just goes up, and there is a stud on the bottom it will go over. Just like that. Our hardware broke off, so I found some appropriately sized hardware. The thread is M6 by 1.0, so just find some bolts and nuts that will work for you. We found a nice flange nut we had in our toolbox. I'll get that started.

And then I'll use these bolts on the top. They don't have to be super long. They just need to hold this cover on. If you've got bolts with smaller heads, they might need some washers. But these should work just fine for us. There it is. Get it in place. Get that one started. And get this one up in here. These ones happen to be 10 millimeter. Yours might be a different size. Just use the appropriately sized socket that you need. And don't over tighten them. Once you feel them get tight, just stop. All they're doing is holding on the plastic shield. Perfect. And tighten the nut down here.

Put the wheel back on. Start your lug nuts by hand. I'll just use the, you can use your socket, or whatever. This is the special socket for these lug nuts. Just tighten them up by hand, and lower the vehicle to the ground. Before you take it off the jack and jack stands, you'll wanna torque these. We'll do that in a minute. Torque the lug nuts to 85 foot pounds in a cross pattern. Reconnect the green connector. It's up here, on the other side of the ground connector. Push it up. It'll lock.

Reinstall the trim panel. This goes around it. And then it sits over this little stud here. As we push it in place, you can clip it down in place, and then that will line up. You'll wanna find this with that, and just kind of screw it on, or it'll just push on. We'll take the white part of it, push it into the body. And then push the black pin in to lock it. And that's complete.

We've replaced the filler neck, so now we're gonna erase the code. Code's been erased, we can unplug the tool and start the vehicle. It may take a couple tries to get it started, because we did just disconnect the fuel pump relay, to release the fuel pressure. Well, it fired right up. Check engine light is off. I'll have to fill the car up with fuel, because the check engine light was coming on at three quarters of a tank. And we'll report back and see if we fixed the code.

Thanks for watching. Visit us at for quality auto parts, fast and free shipping, and the best customer service in the industry.

Tools needed for replacement:

    Materials, Fluids, and Supplies

  • Gloves
  • White Grease

  • Pliers, Cutters & misc Wrenches

  • Vise Grip Pliers
  • Needle nose pliers

  • Ratchets & Related

  • Socket Extensions
  • Ratchet
  • 1/2 Inch Breaker Bar

  • Screwdrivers & Related

  • Flat Blade Screwdriver

  • Sockets - Metric

  • 8mm Socket
  • 19mm Socket
  • 10mm Socket

  • Specialty Tools

  • Trim Tool Set

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