This weekend I have to repair the fuel filler neck on my subaru (97 legacy outback wagon). It's leaking when the tank is close to full. I have the factory manual and understand how to get it off. My mechanic thinks I should be able to patch it without having to buy a new one, so that's good.

Anyway, do I need to drain the tank completely or can I leave a little gas in there when I take the neck off? Since it only leaks when the tank is over 1/2 full, it seems I should be able to remove the filler without getting gas all over the garage. Does this sound right? Do I really need to empty the tank all the way?

Thanks!

hey jb, just like your screenname, JBWeld it, JB. Or use MightyPutty

yeah I was planning on using that JBWeld. It works great and I know it holds up to gas because I repaired some carb overflow tubes on my bike with it! It's held up for 6 months now with now drippage of gas out of the carbs!

I did my 95 legacy a couple years ago , with a 1/4 tank and no gas came out from the tank. I used JB gas tank weld on the hole then covered the whole area with a fiberglass patch just to make sure . There is a plastic guard around the filler neck that hold sand and salt and causes this leak.

Thanks. Yeah that's exactly what happened to me. The dirt and crud built up between the plastic guard and the pipe.

I recently did that repair on my car. No need to emplty gas tank cause the filler tube connects to the upper part of the gas tank. That's why it only leaks when the tank is full.

As said before, you don't have to empty the tank since the inlet is on the top BUT it would be a good idea to pump out the few ounces that accumulate in the low spot of the filler pipe. A few ounces of gas spilled on the garage floor could be very dangerous.

One thinhg you will need to do is to use PB blaster or some type of penetrating oil on the 3 screws that holed the filler neck in. Reach up behind the gas cap area and spray them from the back side. Mine were rusted in and took a lot of coaxing to get them out. Many folks end up drilling them out because the phillips head screw strips.

One thinhg you will need to do is to use PB blaster or some type of penetrating oil on the 3 screws that holed the filler neck in. Reach up behind the gas cap area and spray them from the back side. Mine were rusted in and took a lot of coaxing to get them out. Many folks end up drilling them out because the phillips head screw strips.

 

Definatley recommended. I try and hit them a day or two before with Liquid Wrench. I think it penetrates better and leaves behind an oily film if you have the time to wait. I use a lot of PB - but usually for stuff I'm basically dis-assembling basically immediately.

 

Another pointer. There is a rubber gasket and those screws typically are tight even when the rust is broken for several turns. And you don't wanna screw up the heads.

 

I frequently use one of those impact drivers to get them started. Then I use it for the first few turns since it's big and meaty and easy to get a grip on and keep sufficient pressure on the bolt. I have scrapped cars with like new filler tubes because the screws/bolts got buggered up and it's not worth the risk of burning down the garage to use a Dremel or something to cut a slot in them.

can this be patched without removal of the tube?

I would think so. just smear your JB on it all around the outside, that otta get it. No need to remove, just use fingers and smear the patch stuff around.

can this be patched without removal of the tube?

I would think so. just smear your JB on it all around the outside, that otta get it. No need to remove, just use fingers and smear the patch stuff around.

 

Probably can be fixed with the tube on the car, but I would like to wire brush the pipe and paint it or at least treat it with rust reformer before putting it back together. Hopefully I can do this job once and for all!

Probably can be fixed with the tube on the car, but I would like to wire brush the pipe and paint it or at least treat it with rust reformer before putting it back together. Hopefully I can do this job once and for all!

 

I did this job on my car last year. You may want to price out a new tube, or a used part. Consider leaving off the plastic guard to keep the crud from building up again. On the other hand, it may help keep the JB Weld protected.

 

Just my $.02.

UPDATE:

Thanks all for the replies, they helped a lot. Here's what I wound up doing to fix my filler neck, this could help people in the future.

I drove the car until it was a little below 1/4 tank, and no gas came out when I pulled the filler. I took the filler neck off, which wasn't too bad. Spray some PB blaster or something on all those screws, it helped me a lot.

I put the filler neck on the bench and wire brushed it clean, which created more pin holes but I wanted to have clean metal. I wasn't sure at this point if this thing was beyond repair.

Not sure if JBWeld would work, I went to the parts store and wound up buying some of this stuff:

 

 

It worked really well and was only $5. After it was dry (it gets real hard) I painted the filler and put it back on without the plastic shield. I am not sure if I will leave it off, I may try to modify it so it doesn't catch so much crap from the road.

anyway, the permatex stuff worked well, dried pretty quickly and hasn't shown any signs of leaking yet. I had a fairly large area on the filler that was rusted with holes, like maybe four inches square of intermittent holes. The patch worked well and I had a little left over.

Thanks again for all the advice!