Fuel Tank Leaks

[gwcolwell]

Have 1974 M20F Exec. Have been on the fence trying to decide what to do and need some experienced advice. Tanks are leaking and staining wing. Need to either reseal or install bladders. Problems are as follows.

a.) Live in Maine. Only two people I can find to do the reseal are WeepNoMore (Willmar, Minn) and Wetwingologists(Ft Lauderdale, Fla). Both appear to be very competant. However the cost and inconvenience of transport make the total bill approximately $10k.

b.) bladders are an option. 8 bladder system is $8k. Installation 40-50 hrs. Even at $50./hr I'm back at the $10k figure(plus transport costs to Pennsylvania and back)

Have mechanical gauges in tops of wings. Am told that if bladders are installed, those have to go. Considering the in tank senders have been overhauled twice and worked for only a month afterward, don't really want to do away with the mecahnical gauges.

c.) Can reseal the tanks myself. Have the ability. Time is an issue(always). Lack of chemical product knowledge and procedure knowledge are an issue. Would like to have someone around, looking over my shoulder while the process is taking place.

Would like someone experienced to chat with.

Please advise.

[1964-M20E]

If you have a mechanic that is willing to supervise and sign off on the work yes you can do it yourself. I have never done it before but contemplating it. I hear it is a messy time consuming process but I do not think nay of it is that technical or requires any great special skills.

[TonyPynes]

At the risk of having the wrath of others come down on my head I will offer you my experience.

There are many companies out there that speciailize in fuel tank sealing beyond those usually mentioned on this and other Mooney lists. These are the companies that seal higher end aircraft on a daily basis. My M20F was in my MRO shop for other things when I asked them who they would recommend and it turned out the cost was much less and it has been several months now and no leaks and it was less than quotes I had received from others.

I was surprised at the cost difference but apparently the company I chose seals many aircraft around my area and so for them it was no big deal.

I could have done it myself with an A&P overseeing but this is a messy and nasty job that is easy to get wrong and if this isnt your specialty you are not going to have a fun time doing it and you may very well get it wrong....even if you are an A&P.

If you have questions or want to know more contact me privately.

YMMV, lots of threads on this issue.

[richardheitzman]

This is one of the toughest decisions you will make with a Mooney. You have to remember that 40+ years on sealant is long, very long. It is just like overhauling your engine. Eventually you have to pay. You can patch and patch, and it will drive you crazy or you can bite the bullet and have it done the right way.

If you own a vintage Mooney, you are either preparing to reseal our tanks, have already resealed your tanks, or bought an aircraft with resealed tanks.

So which way to go. I recommend NOT doing it yourself. After stripping and resealing tanks myself a number of times, I would rather cut off my left leg than do it again. If you have never done it before and you are not a professional A&P mechanic with tools, shop, equipment and lots of time, then leave it alone.

The weep no more system is awesome, and they have it down to a science. The finished product is as good (better) than new, with a warranty. Flying back and forth is the least amount of your worries when it comes to the cost of having your tanks resealed.

I am not a fan of bladders. So no point in me discussing them.

Point is, this is a known vintage aircraft upkeep expense, similar to engine overhaul. Once they start leaking it is time for a reseal. Period. The only area that I would say, if leaking, that does not need a complete reseal is the upper access panel under the wing walk. That area is known for leaking due to the flexing of the panel when people walk on it.

Bite the bullet and get it done, the right way. You will raise the value of the aircraft, and have the knowledge and comfort knowing that it was done right, the first time. No issues.

If you cannot afford to do it, sell the aircraft or take on a partner to help with the expense.

Rich

[richardheitzman]

If you have a mechanic that is willing to supervise and sign off on the work yes you can do it yourself. I have never done it before but contemplating it. I hear it is a messy time consuming process but I do not think nay of it is that technical or requires any great special skills.

I disagree with your comment about not being technical or needing any great skills. If you have not done it before, how would you know? I have seen serious internal damage done to wings from technicians who thought they knew what they were doing when stripping wings. This is not an easy task nor is it a simple task. Due you know how to purge a tank? Do you know what tools you need to strip of sealant? Do you know how to chemically prepare the metal to insure bonding of the new sealant? Do you know how to check for leaks?

Do you know how to test the fuel sending units and calibrate the system after you are done with the tanks? How about inspecting the tanks for corrosion? Repairs?

Ok I am stepping off the box now.

R

[Piloto]

Keep in mind that there is a difference between just a leak repair and a total tank reseal. A leak repair could be as low as $500 while a total strip and reseal could be $10K. This is a messy job that requires hangar facilities and some experience with the actual process. Nothing more frustrating that after you finish the job you end up with more leaks. Patching a leak is the easiest way to fix the problem but there is no guarantee that others will show up. Determining the leak point inside the tank requires some experience dealing with the problem since the outside stain does not necessarily coincides with the location inside the tank. My overall advice is to leave it to someone with experience.

José

[DrBill]

I went through this just a few months ago. Given I have a 3 hour bladder and to be honest, I GAINED 1 GAL capaciity, I went with the 3 bladder system and had it done at the factory, O&N near Scranton PA. They have a month backlog which worked great on getting a cheap round trip airfate from Scranton to Charlotte. I left the plane there a week.

Their price was good for install and they re-calibrated the fuel gauges and the new LOCKING caps look great. I made new "dip" sticks for the tanks but they are real close to the old ones. No more worry about leaking or re-sealing. In my opinion about the same money outlay as a complete re-seal. They took me to the airport on a Saturday and picked me up on the way back. Had lunch at a real nice "local" spot near the airport.

I'd do it agian. No more stains.... ever. IT was a bit over 3 hrs each way but worth it.

BILL

[rbridges]

great first post. You don't realize the can of worms you just opened. lol.

anyway, I went with bladders b/c it was much easier to get my plane to the local MSC than to fly it to Wilmar or Ft Lauderdale. I don't think you can go wrong with either choice, but my advice is to go with one of the 3.

I'm very pleased with my bladders, but my choice was easier since I have a C model. In my mind, it's basically a glorified 2 seater. I don't plan to use the back seats for much more than a small kid or luggage, so the extra 30 lbs was no big deal. Also, I gained 2 more gallons of fuel capacity. Since my plane is hangared, and I keep fuel in it, I figure the bladders will be around longer than I will.

If I were equal distance from Wilmar or my MSC, it would have been a hard choice, but I probably would have gone with the strip/reseal.

[AmigOne]

What I have heard on reseals is that they are expensive (unavoidable) and that the warranty (if there is one) is short (6 months?). In addition the cost of taking the airplane back can be substantial. On the other hand, bladders last a long, long time so in a way the warranty is not an issue. Also is seems that with bladders you also gain a couple of gallons of capacity.

[Hank]

I had mine stripped & resealed last fall in Ft. Lauderdale (wet wingologists). Don't remember if the warranty is 5 years or 7 years, but it's a long time. Shop the discount airlines, I went round-trip FL to WV for $143. PM for details, but Mooney tanks is Edison's whole business, and he gives a discount for MAPA members. You'll get some good cross-country time going down and back, too. I'm quite happy, and not used to the sudden lack of blue spots on the hangar floor.

[rbridges]

What I have heard on reseals is that they are expensive (unavoidable) and that the warranty (if there is one) is short (6 months?). In addition the cost of taking the airplane back can be substantial. On the other hand, bladders last a long, long time so in a way the warranty is not an issue. Also is seems that with bladders you also gain a couple of gallons of capacity.

Wilmar has a 7 year warranty. it's the same as the one provided by O&N for their bladders. As Hank mentioned, Wet Wingologists provided a similar warranty. I don't think you can go wrong with any of these choices. People will argue both ways, but anything is better than a leaking fuel tank.

[gregwatts]

My 81 J model is at Wetwingologists now having both tanks done. Bladders not my thang!

[N601RX]

If I were thinking about doing the work myself, bladders would be my choice. I would not even think about stripping and resealing if I had to the work myself, but would have no problem doing the bladders myself.

I have a copy of the bladder install instructions if you would like a copy.

[lamont337]

If I were thinking about doing the work myself, bladders would be my choice. I would not even think about stripping and resealing if I had to the work myself, but would have no problem doing the bladders myself.

I have a copy of the bladder install instructions if you would like a copy.

I'd like to take a look at those. If the need ever rises, I think I'd lean toward bladders since I have the early 48-gallon tanks. PM sent.

[gwcolwell]

Your collective wisdom and experience is overwhelming. More confused now than prior to the post. Am presently at Greenville Seaplane Fly In. Have asked same questions to those I know and several gentlemen I don't. One of the vendors displaying at Greenville is an FBO at PWM. He indicates he is capable of addressing my issue by reseal. Initially sounds very good. Expense of the job was estimated slightly less than either Willmar or Ft Lauderdale. Transport cost to PWM are minimal.

New issue? Unfamiliar with the quality of his work. Internal wing damage is not real palitable. Nor is repeat repairs.

[danb35]

What I have heard on reseals is that they are expensive (unavoidable) and that the warranty (if there is one) is short (6 months?). In addition the cost of taking the airplane back can be substantial.

In addition to WeepNoMore's 7-year warranty, it includes his traveling to your location to fix the problems--or so he's posted here in the past.

[rbridges]

Your collective wisdom and experience is overwhelming. More confused now than prior to the post. Am presently at Greenville Seaplane Fly In. Have asked same questions to those I know and several gentlemen I don't. One of the vendors displaying at Greenville is an FBO at PWM. He indicates he is capable of addressing my issue by reseal. Initially sounds very good. Expense of the job was estimated slightly less than either Willmar or Ft Lauderdale. Transport cost to PWM are minimal.

New issue? Unfamiliar with the quality of his work. Internal wing damage is not real palitable. Nor is repeat repairs.

Patch jobs are an unknown. The local MSC quoted me $1000 for a patch but made it clear that no warranty went with it. My feeling is that if one area is leaking, probably won't be too long before other areas start to fail. Unless you're in a bind, I'd go with a complete strip/reseal or bladders.

edit--just reread your post. Make sure he has experience with it. I'd personally go with Wilmar or Ft Lauderdale since they do mooneys all day long.

[fantom]

In my experience, penny wise and pound foolish, especially on jobs like this that require some experience to do well, always come back to bite.

IMO it's smart to get it done right, the first time, by the experts...that would be Wilmar or Ft. Lauderdale. Or you could use my lawn mower repair guy and save a couple of thousand.

[adrian]

Hello,

I am renovating an M20E at Brunswick, Maine (or rather my A&P is!), including resealing the tanks. It is an unpleasant and time-consuming job, and took a lot longer than initially expected to do it properly. It took repeated applications of solvent and a lot of labour to get rid of all the old sealant. Fortunately I'm not paying an hourly rate - if I had been, it would probably have been cheaper and would certainly have been faster to take it to Wilmar.

I decided against bladders because I wanted to add long range tanks (another learning experience.... sealing the new tanks is very very hard when the aircraft has been treated with ACF-50) and also wanted to save weight for various other new toys. Hopefully the 8 month renovation will be finished in the next few weeks!

Feel free to drop into BXM sometime.

Adrian.