I've got a fuel tank leak....need recommendation

[Earl]

Quote: N601RX

 I think that what Joey was saying was that the plane would not be leaking when you pick it up, but he could not promise that it would not start back leaking on the way back home.

I would ask him is he could try to determine the general condition of the sealent by looking through the filler or even removing one of the toplates and make a decision based on that.  If the general condition is good, then a patch seems much more reasonable than a reseal. If the general condition apears bad, then your money would be better spent on a strip and seal.

[Piloto]

Quote: N4352H

Let's not freak out.....Mooney tank leaks are common and usually the result of hard landings and high load taxi turns, rarely sealant condition. A new $10k seal job can get cracked open in one day of heavy handed flying.

 

This is a misconception. If you would have a leak due to structural deformation you would have a more serious structural problem than just a leak. The major cause of leaks is sealant deterioration on the material itself or the bonding to the metal. The sealant is very much like rubber with streching properties. Like rubber it will deteriorate quickly when exposed to heat thus loosing it flexibility, cracking and bonding ability. To reduce the deterioration is best to have the plane hangared. But if that is not feasible then leave the tanks at least half full so the gas will help keep the temperatures down. With little gas in the tanks the temps in daytime can go over 150F inside the wing. You can see the same effect on cars parked outside were the glareshield and the seat material crack. When the sealant has lost its properties it will usually change color and become powdery like instead of rubbery. If you can pull it from the surface with just your fingers it definitely needs a reseal.

Mooney sealing process of sealing after stuctural assembly is more subject to leaks than sealant application (sandwhich in between stuctural members) during wing assembly. When the sealant is sandwhiched in the structural members keep the sealant in place even after it looses its bonding properties. This is the process used by most jet manufacturers and why you don't hear much about leaks on these planes even though the tanks are over ten times bigger than Mooneys. Later Mooneys like the Acclaim are sealed with the sandwhich process.

José

 

 

 

[Earl]

Quote: Cris

Last year at the time I did the pre buy (Jan.) & purchased my 99' M20S it had some leaks which the seller agreed to patch. Unfortunately he wanted the guy who had done the repair to do it again less than a year and just 7 hrs latter. I elected to have my local MSC do it at a higher cost but I did not have to fly the A/C 600 nm back to the sellers mechanic  pay for airfare etc. Anyway had I known that this was the 3rd repair I might have done something differant. I had the tanks patched and so far so good. The previous repair was just shoddy. It depends in large part on who is doing the work. I've been told it also depends on how one lands the A/C. In the long bodies dropping it in can cause a leak or so I am told.  

[Earl]

OK, here's my current strategy.  Am going to fly up to RMG tomorrow and have Joey look into the tank and check the leaks and give me a no BS opinion about the condition of the sealant and the need for a reseal.

If he thinks its patchable I will get it patched and hope for the best recognizing it may not last or other leaks could show up.  If he thinks it should be resealed I will pursue that option expeditiously.

Thanks to everyone on Mooneyspace and with the resealant companies for their input and advice.  Will keep you posted on what he finds tomorrow.

[Immelman]

For reference, the last leak I had was fixed with a patch. It cost a few hundred bux and 2 days down-time... the 2nd day was just to let the sealant set up before refilling the tank.

[rbridges]

I would do the same.  Good luck.  Hopefully Joey will give you good new.

[KSMooniac]

Quote: ehscott

OK, here's my current strategy.  Am going to fly up to RMG tomorrow and have Joey look into the tank and check the leaks and give me a no BS opinion about the condition of the sealant and the need for a reseal.

If he thinks its patchable I will get it patched and hope for the best recognizing it may not last or other leaks could show up.  If he thinks it should be resealed I will pursue that option expeditiously.

Thanks to everyone on Mooneyspace and with the resealant companies for their input and advice.  Will keep you posted on what he finds tomorrow.

[MARZ]

Quote: Immelman

For reference, the last leak I had was fixed with a patch. It cost a few hundred bux and 2 days down-time... the 2nd day was just to let the sealant set up before refilling the tank.

[John Pleisse]

Quote: Piloto

 

[Earl]

Just to clarify again, I have had a few small spots with very minor leakage.  A couple of rivets about the size of dimes and around one of my sumps but nothing major.  A&P surmised that since I left the tanks mostly empty for a week that some of the already weakened sealant finally gave up.  

Could be that or for hard landings or a combination of the two.

[Piloto]

Structural deformation isn't required to tear tank sealant. Look at most fuel stained Mooney wing walks. Call any Mooney service center...they'll tell you they see 4 year old Ovations and TN's leaking like sivs. Sealant in tanks outside, in the sun, half empty on fuel ..."drying out" is the larger misconception. While the sandwiching process is a marked improvement in technique...it is newer sealants that can withstand and stretch with mild torsion.

Sure...sealant gets old and flakes......but look at the author of this thread. His leak wasn't progressive.

[John Pleisse]

Quote: Piloto

Structural deformation isn't required to tear tank sealant. Look at most fuel stained Mooney wing walks. Call any Mooney service center...they'll tell you they see 4 year old Ovations and TN's leaking like sivs. Sealant in tanks outside, in the sun, half empty on fuel ..."drying out" is the larger misconception. While the sandwiching process is a marked improvement in technique...it is newer sealants that can withstand and stretch with mild torsion.

Sure...sealant gets old and flakes......but look at the author of this thread. His leak wasn't progressive.

[jetdriven]

Another + for fuel bladders.  Student pilot style "bang it on" landings, grass strip landings, leave it out in the sun.  Flourosilicone o-rings in the caps.  20 years.  No leaks.  Of course, bummer,  not an option for M20K.

[docket]

GO TO WEEP NO MORE.

[GeorgePerry]

Quote: ehscott

Hank: have you since done a reseal on the tank or just keep patching?  Your plane is a little older than mine which was why Joey thought a patch should work. 

[Earl]

Just got back from Cole Aviation and after inspeciting the tank and seeing where the leak is located (on the outboard portion of the right tank) he was pretty sure based on his experience that a complete reseal is not necessary.  What he does is empties the tank and does a complete coating of outboard tank.  Said he has done numerous projects like this wth good results.

Still debating what I am going to do but am leaning toward having it patched rather than having a total reseal done.  If it lasts me a couple of years (or possibly longer in his experience) so that I can get it done where I want and when I can work it around my business travel schedule.  Will get it done in mid-June when I am out of the country and in the meantime I now have a plane with a 55-gallon tank.  At 20 gallons there is no leaking at all.

I recognize the obvious risk of wasting $1K and having a reseal done shortly thereafter and I will be happy to allow others to say they told me so.    I'll keep y'all posted on my final decision and how it turns out.

[KSMooniac]

Good luck!  Sounds like a prudent decision to me, with just a minor bet to get you a few more years of service.

[Earl]

Quote: KSMooniac

Good luck!  Sounds like a prudent decision to me, with just a minor bet to get you a few more years of service.

[MooneyMitch]

Good choice.  All will be fine. 

[davewilson]

I called several different shops regarding sealing mooney tanks. Monroy has the long range kit and highly recommended JOSE in Fort Lauderdale. He has done hundreds of repair jobs  tanks, all brands of aircraft, as well as mooneys for MANY years. He is not the new kid on the block. I just want to say thank you to jose for taking the time, about a 15 minute phone conversation, regarding the sealing, pros and cons of bladders etc. Long range tanks cannot be added to bladders! Jose will also travel to your airport, for expenses only, to temporarily patch to get the plane to his facility. He is negotiable on his price and will compete with any legitimate shop! DO THE JOB RIGHT, and get those tanks resealed with the best epoxy on the market! Thanks jose, dave wilson Prospective mooney owner.

[GeorgePerry]

Quote: ehscott

Still debating what I am going to do but am leaning toward having it patched rather than having a total reseal done.  If it lasts me a couple of years (or possibly longer in his experience) so that I can get it done where I want and when I can work it around my business travel schedule.  

[danb35]

Quote: davewilson

DO THE JOB RIGHT, and get those tanks resealed with the best epoxy on the market!

[davewilson]

I realize there are no mooneys that can use auto fuel. There are numerous other types of aircraft with wet wings, that can use car gas.  I have heard thru several reliable sources that the ethanol additive in todays auto fuel, will DESTROY these approved sealants. Any one heard otherwise. What really surprises me is that ALL automobiles, ancient and contemporary run just fine with this ethanol additive. No problems with leaking seals, O Rings, fuel injectors, hoses or gaskets? There should be a sealant that will stand up to ethanol!

[Jeff_S]

Quote: ehscott

Just got back from Cole Aviation and after inspeciting the tank and seeing where the leak is located (on the outboard portion of the right tank) he was pretty sure based on his experience that a complete reseal is not necessary.  What he does is empties the tank and does a complete coating of outboard tank.  Said he has done numerous projects like this wth good results.

Still debating what I am going to do but am leaning toward having it patched rather than having a total reseal done.  If it lasts me a couple of years (or possibly longer in his experience) so that I can get it done where I want and when I can work it around my business travel schedule.  Will get it done in mid-June when I am out of the country and in the meantime I now have a plane with a 55-gallon tank.  At 20 gallons there is no leaking at all.

I recognize the obvious risk of wasting $1K and having a reseal done shortly thereafter and I will be happy to allow others to say they told me so.    I'll keep y'all posted on my final decision and how it turns out.

[N601RX]

Quote: Jeff_S

Joey patched one of my tanks last Fall and so far it's held up just fine. That may not be enough time to really tell, but as I said, so far so good. In doing this work, he also noticed that whoever had patched this tank before had covered up some important drain holes that allow fuel to flow from the outer tanks to the inner ones. So it's highly likely that I was carrying around fuel that was never available to me if I'd needed it (short of doing a very steep turn to the opposite side I guess!).