Wet wing fuel stain below rivet

[180Marty]

Seems a great place to install more access panels on the back side.

The back wall of the tank is the rear wing spar so probably don't want to change that. Here is one more pic that shows how the newer 182's have access panels for each wing bay on the under side that my 180K does not have. In reality it wouldn't be a big deal to make more access holes in the older wet wings on the bottom side assuming the doublers maintain the strength of the original wing skin.

 

[skywagon8a]

THE 1985 185 I picked up new passed white fibers, which were caught in the screen and the injectors.
MTV

I bought several new 180 and 185s in the middle 70s. Each of them had those white fibers on the fuel strainer screen on the first inspection only. Never to return and never found them elsewhere.

 

[aktango58]

The back wall of the tank is the rear wing spar so probably don't want to change that. Here is one more pic that shows how the newer 182's have access panels for each wing bay on the under side that my 180K does not have. In reality it wouldn't be a big deal to make more access holes in the older wet wings on the bottom side assuming the doublers maintain the strength of the original wing skin.
View attachment 65014

I did not say it well. Top skin, over the aft area of the tank was my thought. Essentially behind the original ones near the rear spar. Makes it easier to reach, inspect, repair...

 

[180Marty]

I did not say it well. Top skin, over the aft area of the tank was my thought.

I thought of that after I responded. It does seem a fore and aft access cover for each bay, both on top and bottom, of the wing would make sealing so much easier and better than drilling and removing the top wing skin.

 

[stewartb]

They had to replace a wing!

They chose to replace the wing. I think his summary about maintenance costs on old airframes is interesting. I also found his comment about well-applied sealants lasting for 40 years is worth considering. How old is that 185?

Sometimes the old stuff serves us better. Bladders are easy enough to replace. And flexible so not compromised by airframe flex, plus less prone to rupture if a wing gets bent. I considered using a bladder in my Cub wings. I still think it may be a good project to try.

 

[hotrod180]

......Sometimes the old stuff serves us better. Bladders are easy enough to replace. And flexible so not compromised by airframe flex, plus less prone to rupture if a wing gets bent. ....

I've heard a lot of reports of leaking wet wings on later model Cessna's.
One later model 182 on my airport has had the tank(s) resealed more than once.
Makes me glad the early 180's like mine had bladders--
yeah, they go bad, but are if not easy at least relatively straight-forward to replace.

 

[BC12D-4-85]

I've seen the lower skins of a C-185 move or drum some in flight. Heavy fuel and on floats. Not sure why, but the floats tend to change the airframe's vibration nodes so the wings get a focus. If there's movement of the lower skin I suppose the rivets can get stressed.

For example locally there's a couple of Cessna's with the winter's 30#/sq ft total snow load. The wings are twisted aft behind the strut with the ailerons bent down, and the lower skins on the C-150's are well wrinkled around the rivets.

Gary

 

[mvivion]

I bought several new 180 and 185s in the middle 70s. Each of them had those white fibers on the fuel strainer screen on the first inspection only. Never to return and never found them elsewhere.

This one went on for the first 150 - 200 hours, then stopped. The gent I spoke with was pretty sure someone left an entire rag in one tank. He said a little "fuzz" was "normal", but not that long.

I got really good at landing out somewhere, pulling the top cowl, finding the plugged injector, removing, cleaning and replacing, then continuing with the flight. I have no idea how many times I did that, but it was a lot.

Our mechanics tried really hard and long to find the source of that stuff with no luck. They drained fuel, and got in there with light and mirrors, but all you could see in there was black mung. I spent a few hours searching, and trying to probe suspicious "lumps" in the sealant, with no luck. It is REALLY hard to reach all parts of those big flat tanks.

MTV

 

[behindpropellers]

So.... Did you buy it?

 

[nanook]

A solid rivet properly driven in the correct size hole will seal without needing a sealant. I would expose the shop heads in that row and hit them again with a gun and bucking bar…they may have just been under-driven. Do not apply sealant until you leak check them. After you are sure that the rivets sealed, then you can pro seal the shop heads/seams, and wait 24hrs at room temp (70) to cure. If you think these are hard to get to, wait until you get to change a flap rail.

 

[Rob]

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 wonder what this mechanics solution was for sealing the top skin / rivets? I see way more wet wings start leaking on top than on bottom, from sitting parked outside with a little less than full fuel.

I think virtually all wet wings are subject to leaking at some point in their life, if that life is anything more aggressive than a benign Sunday morning airport to airport flier. Purchasing an airplane to see off field operations and not considering sealing a weep or leak or potentially resealing an entire wing is about as realistic as pretending a bladder will never have to be replaced. It is the same concept after all, the sealant / bladder needs to remain intact and flexible to work. Age, drying, and movement all work away at them.

Buy it right, hope to never need to reseal while you own it, but plan on doing it should the need arise, and you'll have no surprises.

Take care, Rob

 

[Charlie Longley]

That’s a pretty small leak that is not active. The biggest PITA on sealing a leak like that is de-fueling. If it’s not active I would just monitor it.

 

[mvivion]

That’s a pretty small leak that is not active. The biggest PITA on sealing a leak like that is de-fueling. If it’s not active I would just monitor it.

In my opinion, there is no such thing as an “acceptable” fuel leak. Your mileage may vary. In my experience small leaks often become big leaks, and usually at the most inopportune time and place.

MTV

 

[nanook]

De-fueling is manageable. You will need to leak check your work. Only one way to find out how bad it is, clean it up and top the tanks. Go fly the thing around and see what you have…Wet wing leaks usually don’t fix themselves…

 

[Rob]

I have no problems with wet wings, and will always have a few (work airplanes). But as expected, have had a couple negative experiences with them. Here's a thought for anyone that thinks they will never leak and need repair. Every wet wing I'm aware of gets 8802, flame master, pro seal, or similar on seams and leaky rivets. And many, but not all, mechanics use one or more of these same products on windows and windscreens. I bet you can't walk the length of a busy ramp and not find a airplane that has one of these sealants coming off in strings. Think of that in your fuel tank

 

[180Marty]

I wonder what this mechanics solution was for sealing the top skin / rivets?

I'm not sure but my plane wasn't the only one done that way. Quickdraw1 from Omaha posted this back in 2018 and said they took the wings off and sent them somewhere. The top skin was removed and you can see the bare metal in this picture. I wonder if it is to get it really cleaned up inside before resealing. I was reading Weep No More at Willmar MN and how he has a sprinkler system for recirculating sealant remover around in Mooney wings. I left a message but the guy never returned my call. Wouldn't it be nice if once cleaned up, you could spray something like Plasti Dip around all the places that would leak.