What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Fuel tank leaks

I

Indy

Active Member
I got my RV-4 painted late last year and have since developed fuel leaks on both wings.

The one on the right wing is around a rivet. The painters told me about it when I showed up--said it was leaking was already there when they stripped it. That's possible I suppose. It's out of my line of sight when I'd sump the tank.

The one on the left wing definitely showed up after the paint job but I can't say exactly how long after (but within a month for sure)seems to be leaking around the fairing and screws. Today, for the first time, I actually saw slowly dripping fuel from the aft/inboard corner of the fairing.

Caveats:
I was not the builder.
I have not yet removed the wing root fairing to see what more I can see.
I have slosh, am aware of Vans' service bulletin, and have read the threads. There is no sign of the slosh being loose when I'd try to scrape it.

Any advice from the RV community?
Right wing leak
30sx2px.jpg

Right wing leak location
2ryr9jd.jpg

Left wing leak
2m6uxxe.jpg
 
I feel your pain...

I've struggled with tank leaks on my RV-4, too. The one in the right tank is fixed, the one in the left tank, well, almost fixed.

I can't comment on what you should do about the slosh. But, judging from where the leak starts on the left fairing, you may have leaking around the fuel sender plate. If it was leaking only along the back baffle, I wouldn't expect to see staining that far forward.

I would suggest you pull that fairing soon and take a look. Fuel seeping out and evaporating is one thing. Leaking enough to drip is totally another, IMHO.

I had a similar issue in June of last year. I had seeping, but no dripping. I was slated to leave for ID from FL with some RV buddies on a Saturday. On Friday I went out to load and thoroughly preflight the plane. I found fuel dripping from exactly where you see it. I delayed the trip for 4 days while I pulled the tank and made a repair. My comfort level was exceeded when the fuel leak was bad enough that it dripped.

YMMV,
 
Last edited:
I went through the same thing with my first RV-4: a bad leak that looked about like the one in your picture and big pieces of slosh coming loose. If there's just a little slosh carefully applied in the seams over the pro-seal it's likely to be ok, but if there was a bunch poured in there and literally sloshed all over the place, you're in trouble (or soon will be).

With mine I took the tanks out, cut 4 or 5" round openings at the rear of each bay, went through about 8 cans of laquer thinner/MEK getting all the slosh and proseal out. And then complete re-seal with proseal only. What a nightmare job. (And then re-painted the tanks too of course.)

I've heard it's difficult to match up a new set of tanks, but I'd explore that option before going through what I did.
 
Indy, you're going to get a lot of different opinions on this, but you definitely want to pull that left tank and investigate the source of the leak. It will probably be fixable but you have to zero in on exactly where the leak is. Then possibly you will have to cut an inspection plate in the rear bulkhead as many have done in the past. This will also allow you to get a good look at the interior of the tank and the sloshing compound and decide if you can live with it.

You say you're not a builder. If you don't feel you're up for this repair, find an RV builder on the field or nearby who can fix this for you and make him your best friend.

I wouldn't worry about the other wing just yet. That looks more like a weep and there may be a couple of options on how to fix that, e.g., you may be able to apply a vacuum to the tank and suck in a sealer of your choice. Or you may have another option. But there is no rush to do this right away. Get that left tank fixed, that's the bad one.
 
Tank Leaking

I have heard green loctite, don't have the number, will wick into and seal some leaks.Worth a try. Indy I am a Tech Counselor for 1114 in your area and we are building a set of 7 wings and tanks for a chapter project. We just started the tanks, second session tomorrow evening, if you want to see what it is all about you are welcome. We could probably work out a deal to build you a set as well.
Terry
 
Last edited:
leak

My tanks were sloshed as well. none coming loose but I do keep an eye on the gascolator screen for evidence.
I had a leak in my left fuel tank and it turned out to be the flop tube in the tank. It had worked loose and I removed it and replaced it with a fixed fuel line and finger screen.
I think removing the tank for a look is a good first step. Good luck.
 
fuel tanks

I had the same problem with my 4 when i bought it. I was not the builder either and i had Evans aviation on the west coast build mine. Did a really nice job. I did take him a long time to get them done but he was very good to deal with. My tanks has "slosh" in them i was not fly n it with that **** in them. If you need evans number let me know. hope this helps.
V
 
loctite

I just sent a e mail to Loctite to possibly gain knowledge on a product of theirs called h8100. trying to see if they are aware of its use with tank sealers , in new construction, as a bond for the ribs to skin and ribs to baffle , and after cured apply proseal or what ever one decides to use to finish the tank. encapsulating the 8100 under the sealant. this bonding agent may work in concert with the rivets and sealant. I humbly ask please don't hit me too hard for trying, I just thought of this and I'm sure its been thought of before but if I don't ask I will not learn
 
tank leaks.

Indy said:
I got my RV-4 painted late last year and have since developed fuel leaks on both wings.

The one on the right wing is around a rivet. The painters told me about it when I showed up--said it was leaking was already there when they stripped it. That's possible I suppose. It's out of my line of sight when I'd sump the tank.

The one on the left wing definitely showed up after the paint job but I can't say exactly how long after (but within a month for sure)seems to be leaking around the fairing and screws. Today, for the first time, I actually saw slowly dripping fuel from the aft/inboard corner of the fairing.

Caveats:
I was not the builder.
I have not yet removed the wing root fairing to see what more I can see.
I have slosh, am aware of Vans' service bulletin, and have read the threads. There is no sign of the slosh being loose when I'd try to scrape it.

Any advice from the RV community?
Right wing leak
30sx2px.jpg

Right wing leak location
2ryr9jd.jpg

Left wing leak
2m6uxxe.jpg
Click to expand...

Removing the wingroot fairing will show you the end of the tank , fuel sending unit and not much else. You will not see the back of the tank which is probably where your leak originates from. I had leaks in both of mine and I had to remove , de-slosh, re-seal, after cutting access panels into the tank back. regular paint remover worked well on the slosh to remove it and does not seem to effect the proseal
Its a lot of work but it has to be done..
Having a heated garage to work in helps a lot this time of the year!
 
You must log in or register to reply here.
Back
Top