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Fill Vent Repair - P0440 Code

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Hey all. Did some service today and figured I would snap some photos and do a quick write up.


I had a CEL code P0440, that one has something to do with the EVAP system leaking. After weeks of searching for the cause and scratching my head, today I finally found it. Where the fill vent goes through the frame rail near the passenger side rear tire, the metal pipe simply rusted away. I had already checked my fill pipe a few times since that is one of the most common causes of the P0440 code but this little piece escaped my eye for quite awhile!! One of the worst things was that I couldn't put more than 1/2 a tank of gas in the vehicle without getting a horrendous headache inducing gasoline fume smell.


Once I found where the fumes were leaking out, I despaired a little. It was a kind of a pain in the butt spot and I couldn't find that part for sale anywhere without buying the whole filler neck assembly for $100+.

Enter my step-dad: he recently repaired his truck's filler neck with some 1 1/4" copper pipe. He showed me his repair work and we decided to give the same concept a go on the Subaru. Scrounged up some 5/8 OD copper tubing, cut & bent a piece, voila!!


No more fume smell, no more CEL!!!!!! Oh, and it cost me $0. Free labor and a piece of scrap copper.


Imgur Album:




Car is jacked up and ready to go.



The smaller diameter pipe on the right is the one that rotted through. These "Before" images are actually from a '95 Legacy, I forgot to take photos before doing the work to my '97 Legacy.



Close up of where the vent pipe goes through the frame. The plastic grommet extends through the frame and trapped a lot of dirt and moisture, causing the pipe to rust right through.



This is the other side of the frame rail where the vent pipe ends and connects to the rubber vent hose that goes to the gas tank. The hardest part of this service was getting up in there to unhook that clamp. On my '97 Legacy there are three hoses that aren't on this '95 which go to the charcoal canister. (The '95 has the canister under the hood instead of behind the rear passenger wheel)



You can see that the pipe is quite corroded and swollen from the rust. I was able to grab on and wiggle it quite a bit. The part of the pipe that is visible on the outside of the frame rail wasn't moving whatsoever so I knew there was a break inside the frame.



After pulling out the filler neck and vent assembly, here is the rusted out vent pipe and the grommet it runs through.



You can clearly see that the worst of the rust happened right inside the protective grommet.



Pic without the grommet. Nasty.



Here you can see my tungsten carbide ring is nice and shiny despite the road grime xD



5/8" OD copper tubing. Bent it to shape and size, wrapped some electrical tape to bump up the OD for a snug fit, went together smoothly. I accidentally broke the bolt that holds the vent pipe bracket and filler neck to the chassis but oh well. Zip ties are in my future! Will probably also stuff some cloth or rubber around the copper pipe so it doesn't rub too much against the frame. In this pic you can actually see the three black rubber hoses that come to and from the charcoal canister. They are visible in the bottom left of the photo.



One last note, this was made much easier by removing the filler neck tube. It wasn't completely necessary but it opened up a lot of maneuvering space for my hands.

Edited by Injulen
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