Cardiff Kook
PATRON
Sisters, OR
Dry to the touch- not sure if its old. Bottom side of wet wing on 1979 Skywagon
How big of a deal to fix?
Wet wing fuel stain below rivet
- Thread starter Cardiff Kook
- Start date
Dry to the touch- not sure if its old. Bottom side of wet wing on 1979 Skywagon
How big of a deal to fix?
BC12D-4-85
SPONSOR
Fairbanks, AK.
What's the owner/seller got to say about the stain? History of leak-leaks more with full fuel load above-in flight (rough air?) or sitting? Stuff like that.
Edit: Watch out for "they all do it".
Gary
Edit: Watch out for "they all do it".
Gary
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Cardiff Kook
PATRON
Sisters, OR
Isn’t it the same “fuel system” as any wet wing cessna? Aren’t virtually all single piston
Cessna’s since 1979 wet wing? If so- wouldn’t basically any GA mx shop be familiar with this fuel system?
Cessna’s since 1979 wet wing? If so- wouldn’t basically any GA mx shop be familiar with this fuel system?
mvivion
SPONSOR
Bozeman,MT
Nope, because not all shops work on all aircraft types, for one thing. And not all mechanics are widely experienced. You’re assuming every mechanic has a broad and comprehensive experience base. Not necessarily the case.
And, some shops “specialize” on one or another type, and even specific repairs.
MTV
Ken Robbins
Registered User
Petaluma, CA & Kasilof, AK
There are a number of wet wing specialists around the country but this should not be beyond most shops/mechanics. It will be a lot of work to address correctly but not a technically difficult job. I've frankly had more trouble in getting the top access panels to seal up than lower rivet leaks.
My approach for rivet leaks is to access the inside as much needed (don't be shy), clean all sealant from around the leaking rivet tail from about the mid way point between any adjoining rivets. I am a believer in re-setting the rivet with a gun/bar to be sure it is not starting to work. It seems to prevent a recurring leak (especially in Mooney's). Clean it some more and apply the sealant exactly per the instructions and create the environment needed per the instructions. Temp range important for mast sealants and cure time really needs to be followed for full cure before fueling.
Some sealants have adhesion primers available that are not generally in the manual, they are really toxic but really work well. The worst part of the job is the removal and clean-up. getting all the sealant chunks and flakes out of the tank sucks, an air siphon vacuum is a life saver and are not expensive. The aft edge requires long arms mounted to young bodies and a lot of the job is by feel but it is doable.
The pic looks like the neighbor rivet might be getting some color as well. You would likely find there is fuel under the paint around the rivet head, until the paint cracks it doesn't leak much. Like anything else on a plane, wet wings can give trouble but it isn't a regular sort of event here in the shop.
Just more free advice that may be not worth the price.
Ken
My approach for rivet leaks is to access the inside as much needed (don't be shy), clean all sealant from around the leaking rivet tail from about the mid way point between any adjoining rivets. I am a believer in re-setting the rivet with a gun/bar to be sure it is not starting to work. It seems to prevent a recurring leak (especially in Mooney's). Clean it some more and apply the sealant exactly per the instructions and create the environment needed per the instructions. Temp range important for mast sealants and cure time really needs to be followed for full cure before fueling.
Some sealants have adhesion primers available that are not generally in the manual, they are really toxic but really work well. The worst part of the job is the removal and clean-up. getting all the sealant chunks and flakes out of the tank sucks, an air siphon vacuum is a life saver and are not expensive. The aft edge requires long arms mounted to young bodies and a lot of the job is by feel but it is doable.
The pic looks like the neighbor rivet might be getting some color as well. You would likely find there is fuel under the paint around the rivet head, until the paint cracks it doesn't leak much. Like anything else on a plane, wet wings can give trouble but it isn't a regular sort of event here in the shop.
Just more free advice that may be not worth the price.
Ken
aktango58
FRIEND
18AA
Great catch!! I had to go back to the picture as I only saw the really bad one.
There is a fuel stain on all three rivets in that row when I expanded the photo. Could there be an aft spar issue causing a twist or movement to create the leaks?
Serious hypothetical thought there from me on very limited knowledge- but wanting to learn.
Cardiff Kook
PATRON
Sisters, OR
Crap. I see the bigger stain now. Amazing I didnt even notice in person
BC12D-4-85
SPONSOR
Fairbanks, AK.
The "halo" stain circling the rivets may be permanent. What does the owner/seller have to say about this issue? Most anything can be fixed for the right price.
Gary
Gary
Cardiff Kook
PATRON
Sisters, OR
I rubbed on it for a few seconds with my finger- it was on there and i couldnt get it to smudge. May have been under paint?
Cardiff Kook
PATRON
Sisters, OR
I will call to get more details.
When I mentioned it he said it had appeared “sometime in the last year.” He didnt think it was a big deal to address so the conversation moved on.
BC12D-4-85
SPONSOR
Fairbanks, AK.
Ok. You know what to do next.
Gary
Gary
mvivion
SPONSOR
Bozeman,MT
That might be an indication of the care/attention that plane has received. Or not. But a fuel leak like that needs to be fixed.
MTV
Cardiff Kook
PATRON
Sisters, OR
Here is what the Cessna service manual has to say on leaks
Formandfunction
MEMBER
Leak can be fixed but that stain will be there till you repaint it. If I had to build a story like a detective I would guess that the leak is a decade old and the owner just lived with it. Would make me wonder what else he lived with or how long he let the oilchanges slide. It's all reciprocal and a planes real condition is only as good as the owner/maintainers anal tendencies. Of course supply and demand dictate what we have to work with.
Cardiff Kook
PATRON
Sisters, OR
Reasonable to ask seller to fix it? I told him anything having to do with airworthiness i want fixed. Seems gray as to whether its airworthiness issue per cessna manual if its not actually dripping.
mvivion
SPONSOR
Bozeman,MT
If he doesn't fix it, you should. I'm not a mechanic, but I wouldn't let that slide on an inspection. One thing about leaks: They rarely fix themselves, and they often get worse. The fact that a neighbor rivet also has stains also suggests this may be bigger than you think.
MTV
Perfectly safe and legal to operate as-is, per Cessna and the FAA. Current owner probably doesn’t make mountains out of molehills and uses the airplane for the tool that it is. Should it be fixed? Sure, at some convenient point. Should it be an issue at the sale? Not if everything else checks out, and/or price is right. Of all the things I’d be concerned about on a 180/185 purchase, this is way down the list…
Formandfunction
MEMBER
Yeah,common issue and probably not going to spring a major leak but it does have some paint damage. Pricing accordingly would be appropriate.
You really need to find a shop that can do the repair and ask what the price is going to be. It could be several grand, you want to take that into account if you plan to buy. It would not be a sale stopper for me by any means because you know about it and it can be fixed. I would keep digging hard before you commit. DENNY
Cardiff, I did some reading about wet wing repair. Here’s an article that may help you understand the tanks better. Scroll down for the tank story.
https://www.tennesseeaircraft.net/2017/11/15/when-more-is-less/
https://www.tennesseeaircraft.net/2017/11/15/when-more-is-less/
frequent_flyer
Registered User
Arizona, USA
This link may give some insight into integral fuel tank leaks. The second video of the Mooney leaks puts the Op's problem into perspective.
https://nslaerospace.com/aviation-fuel-tank-sealant-a-guide-to-the-basics/
"That's not a leak THIS is a leak"
https://nslaerospace.com/aviation-fuel-tank-sealant-a-guide-to-the-basics/
"That's not a leak THIS is a leak"
skywagon8a
MEMBER
SE Mass MA6
I've not worked on a wet wing 185. Is there an access panel above the area of those leaky rivets? If so, it should be relatively easy to open that panel to clean off and apply some sealant to those leaky rivets. I see two leaky rivets which at one time made a big mess which has been cleaned off. Notice there is a large stained area of paint covering most of your photo. Look above that top rivet. See the light stain in the paint.
Dry to the touch- not sure if its old. Bottom side of wet wing on 1979 Skywagon
How big of a deal to fix?
Can you post a picture of the top of the wing in this area? This will suggest how to open the tank for repairs. I wouldn't let this keep me from the plane if all else meets your requirements.
mvivion
SPONSOR
Bozeman,MT
Pete,
The only access is to remove the access port surrounding the filler neck. Not very close to this, you’ll want a long, thin arm.
THE 1985 185 I picked up new passed white fibers, which were caught in the screen and the injectors. We searched those tanks a dozen times looking for…..something, with no success. Long reach, big angles, and dark. Eventually, the stuff stopped passing.
Years later, I met a guy who worked at Cessna in those days. Asked him the question: what was the stuff. He said they used white cotton rags to apply and smooth the tank sealer. Apparently, someone fudged their rag count. It was impossible to see even that in that tank, and some very good mechanics tried, as did I.
I hope to never have to muck about in one of those tanks again.
If you’re working in one of those tanks, account for all your rags.
MTV
The only access is to remove the access port surrounding the filler neck. Not very close to this, you’ll want a long, thin arm.
THE 1985 185 I picked up new passed white fibers, which were caught in the screen and the injectors. We searched those tanks a dozen times looking for…..something, with no success. Long reach, big angles, and dark. Eventually, the stuff stopped passing.
Years later, I met a guy who worked at Cessna in those days. Asked him the question: what was the stuff. He said they used white cotton rags to apply and smooth the tank sealer. Apparently, someone fudged their rag count. It was impossible to see even that in that tank, and some very good mechanics tried, as did I.
I hope to never have to muck about in one of those tanks again.
If you’re working in one of those tanks, account for all your rags.
MTV
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180Marty
MEMBER
Paullina, Ia
Here are a couple of pic's of a wet wing. You can see the oval access panels in the top skin. When I bought my 180K with wet wing, the guy said they had to drill and remove the top skin to really do a good job of resealing. I think the wet wing design is great for being simple compared to a bladder if the sealant works. That's a big "if".
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Cardiff Kook
PATRON
Sisters, OR
They had to replace a wing!
aktango58
FRIEND
18AA
Seems a great place to install more access panels on the back side. Extra goop to seal the screw holes.
Yes, it the lower ones will probably leak every 5 years, but like many parts you would remove, clean really well, put new sealant on and reattach.
My guess as a non-A/P is that getting approval for that, even using Cessna parts, would take an act of congress these days.
