Original 1965 tanks haven't leaked yet

[Robert Sailor]

I've owned several Mooney's in the past but that was in the 70's and leaking tanks were not an issue. Now it obviously is...so my question to all you experienced folks is..I'm looking at another mid 60's Mooney and as far as i can tell it's very clean and well kept BUT the owner tells me that the tanks are original and have never leaked. From what I read on these forums it's nice to buy a clean Mooney that has had the tanks done recently..What are the odds that these tanks are going to start leaking sooner than later???

[LANCECASPER]

He might be right. Over the years the EPA has tried to take cancer causing chemicals out of sealants, paints, solvents, etc. One example: Mooney that was painted in the early 90's has better paint than one painted in the early 2000's.

That being said though, nothing lasts forever. I'd say if you buy it, start putting money away for a re-seal. Whether they leak now or not, at some point they will. Even if they never leak, although highly unlikely, on a 53 year old airplane there will plenty of other places for that money to go.

[DVA]

We do a fair number of tank reseals and patching, and I’ve learned that time is not a factor in leaking. Each tank from the factory or through the good shops that do aftermarket chemical striping and resealing know that there are inconsistencies in the process from tank to tank.

That plane may never leak. But the older the sealants gets the more brittle they become. (There are three types of sealants used) Since it has never leaked I’d say you’re now into the luck of landings stage. Your biggest enemy will be an exactly perfect hard landing. The flex moments may now be enough to cause the Buna N top coat to split which is likely the only thing at this point that is keeping the wing dry.

I will advise that if it does start leaking you are not a candidate for a patch. Plan on a full strip and reseal and add that to your cost calculation.


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[Guest]

Newer Mooney’s have a reinforcing stiffener under the panel which is in the wing walk area.  It is distinguished by 4 countersunk screws outside of the access cover screws.

Clarence

[LANCECASPER]

From personal experience, when you put those countersunk screws back in, it helps to put a little Permatex Aviation #3 sealer on the threads and let them cure a day or two before putting the new wing walk back on. Otherwise in a few weeks you are taking the wing walk off again.

[Guest]

It also helps to keep Marauder’s friends off the waning walk.

Clarence

[DonMuncy]

My opinion is that if they are not leaking now, it is a total guess. They may go a long time with no problem or they may start leaking tomorrow.

[carusoam]

A couple of hardware issues to review on a 60s original fuel tank...

my 65C got a few things updated...

The fuel cap seats (there is a name for that piece...?) were not stainless steel... rust bits and holes were a challenge...rainwater entering was a challenge...

The fuel sender seals were original cork... and allowed fuel to go where fuel doesn’t belong...

the connector hose between fuel lines was swollen and crunchy...

Its tanks didn’t leak for a long time after that...

All machines age differently. Depending how they are used and stored...

Good luck with the purchase... not a requirement but it helps...

Best regards,

-a-

[RobertGary1]

They’ve likely had a few minor patches but patches aren’t too big of a deal. Far cheaper and easier than the nuclear reseal. 

-Robert 

[Immelman]

You can buy a lot of patches for the cost and donwtime of a reseal.... a LOT of patches.

 

[RobertGary1]

57 minutes ago, Immelman said:

You can buy a lot of patches for the cost and donwtime of a reseal.... a LOT of patches.

 

And if you ask your A&P to show you how its done you can do it for about $100 in material and whatever he charges to review and sign.

-Robert

[DVA]

And if you ask your A&P to show you how its done you can do it for about $100 in material and whatever he charges to review and sign.
-Robert

So ... Finding the actual leak area(s) is usually 75% of the work, discounting that effort can be an expensive mistake. I can assure you that 99% of the time the leak(s) is/are not in the area of the visual leak.




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[RobertGary1]

4 minutes ago, DVA said:

 

So ... Finding the actual leak area(s) is usually 75% of the work, discounting that effort can be an expensive mistake. I can assure you that 99% of the time the leak(s) is/are not in the area of the visual leak.




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http://donmaxwell.com/fuel-tank-repairs-how-we-fix-them/

-Robert

[Robert Sailor]

Some wonderful information from you guys, thanks a million, certainly an educational experience for me.  Robert