Fuel tank woes

[Patto]

Well, this is what happens when I fill up the left fuel tank all the way.  The fumes inside the cabin were really strong and I must have lost 2 gallons of fuel at least off the top.  It only leaks when it's all the way full from what I can tell.  You can see where it meets the fuselage and climbs a little bit.  Inside, there is a little bit of blue under the beam at the leading edge of the rear seat.

Sad thing is I specifically considered the fact that it had been resealed three years ago as a factor in purchasing it.  It was done by the AP that did the annual from what I can tell from the log book entry.

So, if I fill it to a couple gallons shy of full, it doesn't seem to be an issue, but it really bothers me.  What would you do?  Fix now or wait?  How much am I looking at?

[Raptor05121]

You can always open the top inspection panel and do a spot seal

[carusoam]

That's a get fixed item. Good news, the top is easier to find the source.

you can see the fuel where it goes under the trim piece and climbs up the fuselage...  There is only an old piece of duct tape that seals the cabin from that leak.  If you are smelling fuel in the cabin, that could be why.

Another source of fuel smell in the cabin is the fuel level sensor on the side of the tank. Check the rugs for indications.  The blue coloring is traveling...

How long have you had the plane?

Best regards,

-a-

[Gilt]

http://www.donmaxwell.com/publications/MAPA_TEXT/_overlay/Fuel Tank Repair_How We Fix Them 2-05.htm.   

[Patto]

I have only had the plane for two months. There is an entry in the log book for the fuel tanks being resealed 3 years ago. That is the most frustrating part about it.

Thank you for the responses. I will see if I can determine where the leak is by opening that inspection panel. I will also read that document about how the tanks are resealed.

[Ron McBride]

Call Greg at Advanced Aircraft in Troutdale for information.   Greg did a great job on mine.     Also call whoever did the work about warrantee repairs.

Ron

[Patto]

On 8/9/2016 at 3:27 PM, N803RM said:

Call Greg at Advanced Aircraft in Troutdale for information.   Greg did a great job on mine.     Also call whoever did the work about warrantee repairs.

Ron

I tried Googling the name of the A&,P and came up with nothing useful.  How many hours did your guy bill for it?

[Ron McBride]

I had a full strip and reseal completed on 2 tanks.  3 weeks and I think $8500.00.  Seven year warrantee. Completed on time as promised, Greg took me to Portland airport and picked me up also. Price will very on tank size.  Greg. 503. 465-2298

Ron

[Pictreed]

It's a common problem with the older planes so don't loose too much sleep over it.   After that much time I think the sealant gets brittle.

I purchased mine knowing it leaked and I would do a complete reseal when I got a chance because it appears repairs don't work if you just spot fix.  It's like painting over a rust spot. 

I did notice the blue carpet the other day.  Scared me pretty good because I thought it was corrosion.  But then I found out it was fuel stains. 

Mine will be going in around spring.  I just don't top off for now. The reseal is around $7000.  Make sure they know what they're doing.  Weep No More in Minnesota is the closest to you that I know about.  

[carusoam]

Nice thing about fuel stained carpet...

It may only need some screws tightened evenly on the fuel sender.  Or change the cork seal that is falling apart...

removing the plastic panel may reveal a lot of blue goo.... 

You won't need to wait until annual.  Annual doesn't go behind that panel anyways.  So there isn't any savings to be found by waiting...

Best regards,

-a-

[Patto]

So, $7-8k for the re-seal of both tanks. How much would the fuel bladder upgrade be?

[geoffb]

Upgrade is a strong word.

[mooniac15u]

55 minutes ago, geoffb said:

Upgrade is a strong word.

And it begins...

[Patto]

I guess I'm looking at a seven year warranty on an $8k fuel tank repair or a one time expense of having fuel bladders installed, right? How much are they typically?

[geoffb]

Bladders don't last forever.  Also, if I remember correctly you lose a couple gallons per side with the O&N mod.  Both options are expensive and when I was looking at it I couldn't find a strong advantage one way or the other.  As others have said, if yours are only leaking when topped off, you may be able to have a localized repair done for significantly less than a full strip and get many years out of it.

[glafaille]

While examining potential aircraft for purchase, I happened upon a "F" model that had a long running history of fuel leaks and repairs.  To put the problem to rest, the seller had invested, 2 years prior to my examination, in a total strip and seal at a shop well known for the work but located over 600 miles away from his home.

Since the completion of the repair, the aircraft continued to leak fuel and minor attempts to patch made at subsequent annual inspections.  In fact the aircraft still leaked on the day I looked at it.  I asked the owner why he didn't take advantage of the multi-year warranty offered by the tank repair shop.  His reply was that it was just too much of a pain to fly the aircraft all the way back to the shop, and he just couldn't take the time to do it.  Too busy at work.

Moral of the story?  Unless you live close to the shop that is repairing your tanks, consider if you will have the time to return there for on going repairs if needed.  A warranty means little if you can't take advantage of it.

Having said all of that, I have not seen or heard of a Mooney with bladder tanks that leaked.  I'm sure it happens, but bladders do seem like more of a permanent fix to the problem.

 

[mooniac15u]

2 minutes ago, glafaille said:

While examining potential aircraft for purchase, I happened upon a "F" model that had a long running history of fuel leaks and repairs.  To put the problem to rest, the seller had invested, 2 years prior to my examination, in a total strip and seal at a shop well known for the work but located over 600 miles away from his home.

Since the completion of the repair, the aircraft continued to leak fuel and minor attempts to patch made at subsequent annual inspections.  In fact the aircraft still leaked on the day I looked at it.  I asked the owner why he didn't take advantage of the multi-year warranty offered by the tank repair shop.  His reply was that it was just too much of a pain to fly the aircraft all the way back to the shop, and he just couldn't take the time to do it.  Too busy at work.

Moral of the story?  Unless you live close to the shop that is repairing your tanks, consider if you will have the time to return there for on going repairs if needed.  A warranty means little if you can't take advantage of it.

Having said all of that, I have not seen or heard of a Mooney with bladder tanks that leaked.  I'm sure it happens, but bladders do seem like more of a permanent fix to the problem.

 

It is pointless to debate bladders vs reseal on Mooneyspace. Everyone here is firmly entrenched on one side or the other. Just choose the option that works for you. 

[Andy95W]

To answer the question on price, it depends on the installer.  The last price I saw on the kit was $8400 and probably about $2500-3000 for installation.  My gut tells me that once the warranty is over, resale value of the airplane will be greater with the bladders, simply because some people look specifically for them.

[pinerunner]

Mine (64 M20E) looked pretty much like this last week and its holding up my annual. I had a known leak down on the lower edge which I have apparently found and resealed since it doesn't show any more but now this one on the top. To test we filled the tanks right to the brim and watched over night. Previously I wouldn't quite fill this tank and then would use it up ASAP to minimize the problem on the lower edge.  I'm doing the process Don Maxwell describes (with oversight from the shop at our airport) to find and seal leaks but I didn't see any bubbles on the upper edge (I need a mirror and light upgrade I think). So now I have to go back in and go after this new leak before I can be signed off. They told me they thought I must be on drugs when I said I wanted to learn to do this myself.

My thoughts after this initial exposure to tank sealing.

1. Yes its a PITA. But you learn and get better at it and can save a lot of money. It gets easier when you know what you're doing.

2. My first sealing of the access doors went fine. No leaks there. So I was doing something right.

3. Going back in the second time was quicker and easier. I think they get easier to work on if you don't let them get too old.

4. I like this better than scrapping paint and ZipStrip which I used to do in my dad's rebuild projects. 

5. This gives you a chance to inspect the interior. I noticed that there's a half inch left under the tube (going to the gascolator) where water could puddle long term and never be drained out. There were some crappy flakes there that I cleaned out.

Some of the access panels came off so hard that I think they must have been sealed on with normal sealant instead of the lower adhesion sealant intended for access panels. This takes the PITA factor much higher but getting them back on with the right sealant makes it easier for the future.

Now that I'm not afraid of it I'm planning a complete strip and reseal this winter. I was hesitant before. I like having the problem in my own hands better than flying to Minnesota and spending 8K that I want to spend on a 650 GTN.

If I don't get flamed too bad maybe I'll post some pictures.

I'm sick off being grounded.

Edited August 18, 2016 by pinerunner

[Guitarmaster]

18 minutes ago, pinerunner said:

Mine (64 M20E) looked pretty much like this last week and its holding up my annual. I had a known leak down on the lower edge which I have apparently found and resealed since it doesn't show any more but now this one on the top. To test we filled the tanks right to the brim and watched over night. Previously I wouldn't quite fill this tank and then would use it up ASAP to minimize the problem on the lower edge.  I'm doing the process Don Maxwell describes (with oversight from the shop at our airport) to find and seal leaks but I didn't see any bubbles on the upper edge (I need a mirror and light upgrade I think). So now I have to go back in and go after this new leak before I can be signed off. They told me they thought I must be on drugs when I said I wanted to learn to do this myself.

My thoughts after this initial exposure to tank sealing.

1. Yes its a PITA. But you learn and get better at it and can save a lot of money. It gets easier when you know what you're doing.

2. My first sealing of the access doors went fine. No leaks there. So I was doing something right.

3. Going back in the second time was quicker and easier. I think they get easier to work on if you don't let them get too old.

4. I like this better than scrapping paint and ZipStrip which I used to do in my dad's rebuild projects. 

5. This gives you a chance to inspect the interior. I noticed that there's a half left under the tube where water could puddle long term and never be drained out. There were some crappy flakes there that I cleaned out.

Some of the access panels came off so hard that I think they must have been sealed on with normal sealant instead of the lower adhesion sealant intended for access panels. This takes the PITA factor much higher but getting them back on with the right sealant makes it easier for the future.

Now that I'm not afraid of it I'm planning a complete strip and reseal this winter. I was hesitant before. I like having the problem in my own hands better than flying to Minnesota and spending 8K that I want to spend on a 650 GTN.

If I don't get flamed too bad maybe I'll post some pictures.

I'm sick off being grounded.

I'm with ya brother!  I LOVE experimenting with new things and breaking norms and myths!  That's probably why I like Mike Busch's articles so much!  Aircraft ownership is FAR less expensive if you are willing to take a risk and get your hands dirty!  I feel WAY more comfortable when I know what's been done to my plane and how it was done.

Flame on!!

 

Edited August 18, 2016 by Guitarmaster

[Patto]

I talked to a well known and trusted Mooney A&P yesterday, and it sounds like it would be about thirty hours of labor for just the one side. I'm thinking i will assist with the annual and assist with the fuel tank on the left side at that time. Then, when the right side starts to go, I can do it myself with confidence.

I'm with you guys. I like doing things myself and being involved, but I have very little experience and want to feel confident it was done correctly.

[pinerunner]

Update on my right upper surface leak. Although I didn't see bubbles the first time I tried it using cheap mirror and only looking up from the bottom, the second time I did the Don Maxwell (he says he didn't do it first) trick with a shop vac and soap I did spot bubbles. I was looking up from the bottom access port and didn't need a mirror. The three leaks were near each other and the bubbles I saw were very tiny. My leak isn't a gusher. I'll be doing the sealing of the area tomorrow and filling the tank after 48 hours. I hope on Monday that they'll see no blue and finish off my annual.

The quality of your mirrors, lights, and the windows you're looking through matters. If you're a bit of a hobbyist you might play with that a bit beforehand so you can get as good a view as possible. Small camera's are cheap these days too.  

[Guest]

Mooney taught Texans to do it, Cessna and Beech taught Kansans to do it.  The big difference is they did not have to remove the sealant first.  With training and patience I think most could accomplish it.

Doing it fast enough to make a profit and offer warranty is where the others excel.

Clarence

 

[1524J]

2 hours ago, M20Doc said:

Mooney taught Texans to do it, Cessna and Beech taught Kansans to do it.  The big difference is they did not have to remove the sealant first.  With training and patience I think most could accomplish it.

Doing it fast enough to make a profit and offer warranty is where the others excel.

Clarence

 

Agree! Stripping and reselling fuel tanks is not very technical, but beware, it is extremely tedious and you need to be somewhat anal retentive to do the job properly. There are several threads,with good info and some pitfalls to avoid, on Mooneyspace. 

[pinerunner]

Final Update: I finished up the patching job and passed annual. There is still a very slow seep along the lower edge of my right tank. I must have missed a spot that just didn't make enough bubles for me to see.  An important point for me was the success I had resealing the access panels. I had no leaks from any of the access panels I took off and resealed. I cleaned up the exposed edges where the access panel would mate with the skin of the wing using Polygone (the gel kind) that I bought from Skygeek. I wasn't shy about slathering it on before reinstalling the access panels and as you can see in the picture it oozed up though as I tightened the screws. I consider that a good thing since it makes me feel sure I put on enough. Once it cures after 48 hours you can trim it away easily. Any ugly grey stains on the painted wing surface rub away easily since its low adhesion after all and doesn't stick well to paint.

To take the access panels off I unscrew all screws so they're sticking up, place a piece of plywood and 30 lbs of weight on it and leave it overnight so the old seal slowly breaks. On the bottom I do it similar but use a jack pushing up lightly.

Now I feel pretty comfortable going into the tank and looking things over. For the access door sealing I used. 

Flamemaster CS-3330 B-2 Red AMS 3284 Rev. B Type 1 Spec Access Door Sealant - 6 oz (3.5 fl oz) Cartridge Kit

To remove old access door sealant I used

RPM Technology 2035-205 PolyGone 305 Gel High-Performance Polysulfide Depolymerizer / Stripping Agent - 6 oz Jar

I drained a babyfood jar full off fuel from that tank (through the gascolator) before letting the engine sip from there and it was clear.

I plan a complete strip and reseal this winter (though I may put that off if I'm having too much fun flying). I'll buy a gallon of the liquid Polygone for that. That may turn out to be easier in the sense that I won't have have to fuss with finding all the leaks. I also won't have to worry about a stray bit of polygone getting loose and unsealing where I dont want it unsealed. 

They started up on a Cessna 185 (wet wing) leak fix in the shop on-field. It has much less generous access panels.

Edited August 31, 2016 by pinerunner