Leaking fuel tanks

[Marauder]

Our bladders are 22 years old and I have no reason to suspect they are failing. Bonanzas have had bladders since 1947 and a few owners have had to replace them, the latest one I heard of was breaking the nipple off where the fuel drain goes in a 1947 model. The bladder itself was fine at 66 years in service. The other is still the original. Google "cessna bladder leaks". Lots of threads on that. Haven't ever heard of a leaking mooney bladder, but most are still relatively new. At 22 years, yours are the oldest I've heard of. The O&N product does look sturdier than the brand C bladders though....

My plane's bladders are also 22 years old. I had them installed and am happy with them.

[Bob_Belville]

I went through several pages of google search results re Mooney bladder leaks. Found none. I did see a '66C advertised on 4/2013 Aviator Trader listing with 21 year old O&N bladders toted as a selling point: "O&N Bladders installed 5/92,    per STC SA2350CE, eliminating fuel leaks..."

 

There are now at least 500 Mooneys flying with bladders, probably many more than that. If they sometimes leak you'd think we'd see someone reporting it.

[Piloto]

Like the Harley Davidson bikes, you don't have a genuine one unless it leaks.

[mike_elliott]

There are 50 year old bladders still in service in other aircraft. I'm not sure where the 15 year service life that Mike quoted above came from, but I think that it is a woeful underestimation.

 

Jim,

I have only heard stories of bladders being replaced by some A$P's that told of them literally disintegrating when being removed and only being 15 years old. I am sure how they are treated during their life in the wing makes a huge difference. I know back in my racing days, we would replace them every 4 years needed or not. Sometimes they would outlast the cars, however .

While liking the concept of the bladders, I personally felt a proper reseal was the way to go when I added up all the costs, benefits etc., just as you have with the bladders. The key here is one has some viable options to keep their tanks leak free. Do what is right for you, Just know that Paul Beck is one of the true customer focused pros aviation for the most part, lacks the likes of. If one chooses to have him do work for them, they will not be disappointed.

[rbridges]

Not that it applies to the OP, but bladders are only options up through J(?) models. In the bigger Mooneys, reseals are the only option.

[fantom]

There are now at least 500 Mooneys flying with bladders, probably many more than that. If they sometimes leak you'd think we'd see someone reporting it.

500 seems high to me. I suspect that the zealots who have unnatural balloons in their wings are way too embarrassed to admit it when their bubbles burst.

[marks]

Unfortunately, Mooneys are famous for leaks.  Paul Beck at Weep No More in Wilmar MN is so good that his competition recommends him.  I'm one of his happy customers.  No scraping the inside of your tanks, no usable load loss as with bladders, no balony or excuses, Paul Beck is the man.  He is the expert on Mooney fuel tanks.

[Bob_Belville]

500 seems high to me. I suspect that the zealots who have unnatural balloons in their wings are way too embarrassed to admit it when their bubbles burst.

The 500+ number is in the O&N ad in the latest MAPA Log, p. 25, in the context of promoting their add-on bladders for Mooneys that have the basic 54 gallon system to get to 64.

 

I am no zealot but I'm feeling like a salesman again even though I have no personal interest in this matter. I have never even talked to the folks at O&N. I bought a plane that has the bladders and they are fine. OTOH, several on here seem to be willing to run down the bladders with unsubstantiated claims of leaking and worse that they do not back up with any data and I can't confirm on the internet. This medium seems to bring out the worst in some folks. If the bladders are really a serious problem I sure want to know it but vague and false innuendo are not very helpful. That wet wings leak is not at issue.

 

Good grief. 

[Marauder]

Bob -- thanks for defending my bladders! I never understood the controversy -- "bladder envy?" All I can add is that my wet wings were leaking, they were getting worse and the protective coating put on the sealant to protect it from the AvGas was peeling off and filling my tanks with rubber worms. So, I made a decision to install bladders. Twenty-two years later, I am still happy with that decision.

[fantom]

The 500+ number is in the O&N ad in the latest MAPA Log, p. 25, in the context of promoting their add-on bladders for Mooneys that have the basic 54 gallon system to get to 64.

 

 

Such an ad is an impeccable source

 

Come on, Bob, you, and your friends know deep down that putting rubbers in your wings is an unnatural act.  

 

Double 'good grief'.

 

[jlunseth]

I had my tanks done at Willmar.  It was before Weep No More split off from Willmar Air I believe, but the same people and the same process.  That was four years ago and no issues at all so far, and I have alot of landings on the aircraft since then including some grass field work (hard landings are supposed to be hard on the sealant).

[Shadrach]

Bladders are fine, but I would not want the 40ish pound hit to payload. As Jose said, heat (and also oxidation) is the biggest enemy of sealant (and many other compounds as well). Keeping the tanks full helps with both.  I still have the original wet wings in my 67F. I patched them once, 3 years ago, but still have a few stained rivets in areas I probably missed (it was my fist time so give me a break). What it did remedy was the occasional fuel smell we would get in the pattern.  We'll likely get it resealed in the next 3 years, but they are tight enough that any fuel loss that may happen over a few weeks of sitting is imperceptible.  I think the biggest reason for the sealant degradation has been leaving the tank only partially filled. This is anecdotally born out by the fact that the top of the tanks was the only place where sealant was starting to bubble.

 

I do not buy the notion that the condition of the rubber donuts is a real factor, unless the sealant is totally shot.  I think anyone that has worked with properly mixed and applied CS3204 would probably come to the same conclusion; it is tough and holds onto aluminum with great tenacity...Any landing hard enough to cause a tank leak probably means something else has been bent!  I'd like to glue 2 pieces of aluminum together with CS3204 (or even 3330 access door sealant) and see what it takes to get it to separate; my guess is severe and permanent deformation. 

[Piloto]

I agree with you Ross. If you notice most of the leaks start on the wing walk area. This is caused by the black paint that increases the temperature that causes the sealant to fail when left on the sun with no fuel in the area. Your 46 years old wet wing tank proves that these tanks can last that long when treated well.

 

There are two ways of sealing a tank cavity. On the old Mooneys the sealant was applied after wing assembly. But on larger airplanes the sealant is applied during wing assembly. Before the ribs, skin and spar are riveted together sealant is applied to the mating surfaces and then it get sandwhich between the joining surfaces. This application process not only guarantees a tighter sealing but insure long term sealing even in the event of sealant bonding failure because the sealant is held in place by the assembled structure. The sealant also reduces the possibility of moisture trapping between riveted parts, thus reducing possibility of corrosion. After the assembly is done the excess sealant is cleaned giving the impression of a no sealant job. I believe this is the process used on the Mooney Acclaim and late models.

 

When resealing a tank (after stripping the old sealant) it is important that the low viscosity (A2) type be very well brush in into the crevices and gaps of the structure instead of just applying over. This guarantees a longer tighter seal even if the sealant degrades. I believe this is what has made the difference between Mooneys with no leaks for decades vs those leaking just a few years after comming out of the factory.

 

José.   

[marks]

I asked Paul Beck after he finished my job if I needed to keep my tanks full and he said that during a cold winter or in the hangar it made no difference, but that in the sun during summer to keep the tanks full because of heat.  He said that walking on the most flexing parts of the wing walk area rather than on the rib areas is also not helpful.  When Paul at Weep No More sealed my tanks he replaced my gaskets where the fuel lines enter the lower cabin and he got my outer fuel gauge sensors to work again.  Sealant won't fix loose rivets, so the wing has to be in good shape before the process begins and proper channeling must be in place during the process to be sure that fuel can get around and under ribs where required.  -  It seems clear to me that a properly sealed wing can stay sealed for decades and the same can be said for properly installed O&N Bladders.  Bladders however, cost more to install and weigh more.

[Hondo]

OR75  "To be honest,I would have expected the O&N installed price to be higher than the quote you got. (+$1500 vs reseal)

Is that quote for 64 gallons ?"

 

No.

 

The quote for 64 gallons was 12725, 8600 for the bladders and 4125 for labor.  Texas sales tax on the bladders would add about 700.

[OR75]

thanks for clarifying . 13-14amu is more what i had in mind.

[Bob_Belville]

thanks for clarifying . 13-14amu is more what i had in mind.

My 54 gallon system cost $4650 plus $1125 = $5775.

 

(In 1997)

[jetdriven]

Its gone up a bit and bladders are no longer a value proposition.  But they do solve the problem of leaking tanks for a long time.

[aaronk25]

Just had reseal by paul and no issues. I wouldn't rule out buying a plane that has bladders as long as it had 64gallons but I would never add bladders to a bird as the 30lbs loss in useful load is substantial to me.

If I'm gonna loose 30lbs I want it to be on something that has some benefits.

[rbridges]

O&N can install them themselves cheaper than probably anyone else can.  In fact, for only around $1500 more than they will sell a third party the materials/kit. 

 

My 64 gallon system was installed there for $8,900 in 2008.  

 

Agreed.  At 13 or 14 AMU bladders would be a non-starter for me.

 

Jim

 

I think my wallet damage was around $10500 in 2011, and that was for 52 gallons.  I know the closer MSC charged more for labor than O&N would have.

[harrispa]

Looking for a leak repair in Central Florida.  Anyone know of a good place to take it to?

 

Thanks

Paul

[Hank]

800-938-8265

Wet Wingologists in Fort Lauderdale. Edison does good work!

[cnoe]

+1 for Edison in Ft. Lauderdale if you're anywhere in the SE.

I took a partnership M20E there last spring and Edison did a great job on our strip & reseal. His stripping process was not excessively aggressive and the end result looks great and performs well (so far). The attention to detail was very good.

Also, Edison dropped me off and picked me up at KFLL at drop-off and pick-up.

My newly aquired J had a fresh tank job by Paul and it looks equally good. I believe (if you go for reseal over bladders) that it's simply a matter of location and scheduling when choosing Edison or Paul.

Chuck

78J

[mike_elliott]

+1 for Edison in Ft. Lauderdale if you're anywhere in the SE.

I took a partnership M20E there last spring and Edison did a great job on our strip & reseal. His stripping process was not excessively aggressive and the end result looks great and performs well (so far). The attention to detail was very good.

Also, Edison dropped me off and picked me up at KFLL at drop-off and pick-up.

My newly aquired J had a fresh tank job by Paul and it looks equally good. I believe (if you go for reseal over bladders) that it's simply a matter of location and scheduling when choosing Edison or Paul.

Chuck

78J

Its also a choice of mechanical or chemical stripping of the old sealer, Unless Edison now uses chemical stripper that preserves the alodine coating on the aluminum like Paul Beck does.

[mike_elliott]

My friend here with a 67F has more spent resealing than a set of bladders cost. and while I generally fill the tanks, I am not sure that is more of an issue with bladders than with sealed tanks. Not talking dry tanks for months on end... just doubt that 1/2 full bladders in a hanger are at risk. 

Bob, your friend went to the wrong person to reseal the tanks then, plain and simple, but this is why there are so many failure stories out there about resealing your wings and why there is such an attraction to "not chance it" and accept a heaver, costlier fix to a leaking tank. Going to the right guy like Paul Beck to do a reseal completely mitigates this, as he is a pro's pro.

You might want to reconsider keeping your bladders full (heck I tried to get you to SNF to do just that with beer) because just like wet wings, heat is an enemy of bladders. They will dry rot even in a hanger in the heat a lot quicker empty than full. They do in race cars, I am sure they would in planes also. Whether it is more of an issue or less than with wet wings, I don't know, but believe it would be a better practice for either to keep the wings full than not to. What does O$N recommend, do you know?