Ugh. Fuel tank leak

[chrisk]

I went to visit the plane today and noticed the smell of fuel when I opened the cabin door.  After further inspection I found fuel staining on the left hand outer side of the wing.  And before anyone asks, there was no hard landing, the plane is hangered, and the tanks are always refilled when I am done flying.

 

The plane goes to the mechanic tomorrow for a quick look to see if the fuel sender is leaking.  If that is not the cause, it looks like I might be in for a re-seal.  

 

Anyway, I'm planning on painting the plane soon.  Will a re-seal mess up a new paint job?  --It plays into the patch vs re-seal decision.  The current sealant is 32 years old

[mike_elliott]

_{There is a real good chance it is the inboard fuel sender gasget. If you need to get it resealed, I certainly would prior to painting. If you patch, keep in mind you are patching 32 year old sealant, and more than likely, a new leak will spring up in short order, typically 1 week after your new paint job .}

 

_{You have undoubtedly heard the praises of Weep No More for reseal work. Don Maxwell will patch, but sends all the reseal work up to Paul Beck at Weep No More if that tells you anything.}

 

_{Good luck, I hope it is just a few screws on the inboard sender needing a bit of torque}

[Bob_Belville]

Smelling gas inside the cabin... and no stains outside(?) might not be terrible. It could be just the seal around the level sensor access hole which should not be a big deal. If your K is like my E getting the side panel off or perhaps just loose will allow inspection.

[gwcolwell]

Resealed the left hand tank on my M20F. Spot sealed the right. Caused minor paint damage at screw hole area around access panels.  If doing it over again (and I'll have to do the right hand tank sometime soon), I'd reseal the tank and then paint the whole wing so the paint would match. 

[andrew83m]

Hi Guys,

First post so go easy on me!

I'm in the process of examining a 1974 M20F that has a slow leak in the LH tank.

It geared up in 2005 but was apparently repaired to a reasonably good standard, whether the leak is linked or not I don't know, but would like to know what I might be in for if it is leaking, what's the situation for a re-seal? At what point is total tank replacement required?

Thanks,

Andrew

[Bob_Belville]

Hi Guys,

First post so go easy on me!

I'm in the process of examining a 1974 M20F that has a slow leak in the LH tank.

It geared up in 2005 but was apparently repaired to a reasonably good standard, whether the leak is linked or not I don't know, but would like to know what I might be in for if it is leaking, what's the situation for a re-seal? At what point is total tank replacement required?

Thanks,

Andrew

Andrew, post on, this is a welcoming forum. "Tank replacement" would be either a strip and reseal or making a change to O & N bladders. www.onaircraft.com/products-services/mooney-bladders/ There are strong proponents of either choice which you can find by searching the forum for threads.

 

Where are you located? Or the plane you're considering? (Finally, "leak" and "weep" and "stain" or technical terms in this context. You'll want to know how badly the tank is leaking.)

[mike_elliott]

Andrew, post on, this is a welcoming forum. "Tank replacement" would be either a strip and reseal or making a change to O & N bladders. www.onaircraft.com/products-services/mooney-bladders/ There are strong proponents of either choice which you can find by searching the forum for threads.

 

Where are you located? Or the plane you're considering? (Finally, "leak" and "weep" and "stain" or technical terms in this context. You'll want to know how badly the tank is leaking.)

 

 

Hi Guys,

First post so go easy on me!

I'm in the process of examining a 1974 M20F that has a slow leak in the LH tank.

It geared up in 2005 but was apparently repaired to a reasonably good standard, whether the leak is linked or not I don't know, but would like to know what I might be in for if it is leaking, what's the situation for a re-seal? At what point is total tank replacement required?

Thanks,

Andrew

 

If it is the original sealant, it will be 40 years old next year, and you can expect it to sprout new leaks at regular intervals. Just cant understand the poor warranty from mooney Tank patching is about a $500 (.5 AMU) affair by someone like Don Maxwell or Paul Beck (weep no more, willmar, Mn.) Tank resealing is about 7K, (Paul Beck is THE man) bladders are about 10K (64 gal) Both should give you 30 or more years of service. You lose useful load and 3 AMU's with bladders, but gain perceived confidence it shouldn't leak again while you have it. A proper reseal wont leak again either, but they are only guaranteed for 5 years. I have no idea how long the bladder warranty is, maybe 10 years. Bob, you know off the top?

[testwest]

Hey Chrisk

 

Take a look at the wing root area inside the fuselage. You will need to remove some upholstery and panels. You will see where the fuel line comes from the wing and joins the fuselage line. There is a little flexible line right there that might leak. You can buy the correct replacement hose for less than $20 from Aircraft Spruce. If you find this is the issue, I'll dig up the exact details and some pictures.....

[KSMooniac]

If the plane is a long-term keeper, you might want to seriously going with a re-seal prior to the new paint.  If not, just expect to pay a little extra for some paint work after the reseal if it is needed on your watch.

[Bob_Belville]

Bladders also have a 5 year warranty. Willmar used to be just 3 years, but Paul wisely raised it to match O&N. Nice summary, Mike.

On a previous thread there was a fair amount of conflicting opinions - reseal vs. bladders -  but I don't think anyone could provide an example of bladder failure in Mooneys. Several chimed in that they have 20 plus years trouble free bladder experience. The newer reseal materials and techniques have not been around that long. OSISTM.

[jetdriven]

I haven't heard of a single instance of a bladder in a mooney needing repairs. Ours are doing fine at 22 years

[Bob_Belville]

Agreed, Bob. I'm in the bladder camp, too. But Chris has a K, so they aren't an option for him. I was just trying to answer Mike's bladder warranty question.

Jim

My bad. Did not make the connection. 

[Bob_Belville]

I haven't heard of a single instance of a bladder in a mooney needing repairs. Ours are doing fine at 22 years

Mine are 16 year w/o any issue at all. I'm thinking seriously about adding the 10 gallon increase which would make my trips to New England more dependably non stop.

[fantom]

I haven't heard of a single instance of a bladder in a mooney needing repairs. Ours are doing fine at 22 years

 

I have, but not first hand. I have, however, seen several ugly Bonanza examples.

 

Keep condoms in the nightstand, and seal those tanks properly.

[Bob_Belville]

I have, but not first hand. I have, however, seen several ugly Bonanza examples.

 

Keep condoms in the nightstand, and seal those tanks properly.

Ahh, here we go again.   Go Bosox!

[andrew83m]

Hi Guys,

Thanks for the advice, I should mention that I'm based in Sydney, Australia.

According to one of the LAME's that has worked on the A/C prior, it is more of a weep or seeping than leak dripping out and mainly occurs when the tank is full, once a third is out it seems to stop... strange.

[Shadrach]

Hi Guys,

Thanks for the advice, I should mention that I'm based in Sydney, Australia.

According to one of the LAME's that has worked on the A/C prior, it is more of a weep or seeping than leak dripping out and mainly occurs when the tank is full, once a third is out it seems to stop... strange.

It's not strange at all if the plane has been parked out side in the sun with partially filled tanks.  Heat is the enemy of almost all sealing compounds.  Out in the sun with the top of the wing absorbing heat  the sealant on the inside will heat up too if there is no fuel to absorb said heat. "top tank" leaks are common and will only get worse if the plane is left in the sun. I've patched my 46 year old tanks (still original) and they've been holding nicely for the last 2 years. However, I will likely have them stripped and resealed prior to painting.  The stripping process is going to cause paint blemishes, they can be minimized, but there is no to avoid them completely.

[Bob - S50]

FWIW, I've heard it is not good to 'fill' the tanks after flight.  You want some fuel but not full fuel.  If you fill the tanks and the temperature rises, the fuel will expand and exert pressure on the skin and thus possibly damage to the sealant.  I've also heard that it is the fuel vapor in the tank, not necessarily the liquid that protects the sealant.

 

While I'm new to Mooney's we plan to park the plane with 30 gallons.  That keeps the wings wet, leaves enough for a 2 hour local flight, or a reasonable useful load if I want to fly with 4 adults.  We have not had a leak yet (knock wood) but if we do we'll fix or reseal.

 

I don't like bladders because they weigh about 30# which is that much less useful load available.  When researching the purchase of our plane, we also found the cost of purchase and installation of bladders was actually more expensive than a reseal.

[Bob_Belville]

FWIW, I've heard it is not good to 'fill' the tanks after flight.  You want some fuel but not full fuel.  If you fill the tanks and the temperature rises, the fuel will expand and exert pressure on the skin and thus possibly damage to the sealant.  I've also heard that it is the fuel vapor in the tank, not necessarily the liquid that protects the sealant.

 

While I'm new to Mooney's we plan to park the plane with 30 gallons.  That keeps the wings wet, leaves enough for a 2 hour local flight, or a reasonable useful load if I want to fly with 4 adults.  We have not had a leak yet (knock wood) but if we do we'll fix or reseal.

 

I don't like bladders because they weigh about 30# which is that much less useful load available.  When researching the purchase of our plane, we also found the cost of purchase and installation of bladders was actually more expensive than a reseal.

I do not believe full tanks will do what you imagine. There are vents that will port excess fuel overboard. 30# of weight at the fuel station is worth it for decades of trouble free fuel tanks. (My bladders are 16 years old and I do not expect to have to ever service them.) It is true that bladders cost a little more than your FIRST reseal not counting any patching required or paint touch ups.  .

[FlyDave]

I went to visit the plane today and noticed the smell of fuel when I opened the cabin door.  After further inspection I found fuel staining on the left hand outer side of the wing.  And before anyone asks, there was no hard landing, the plane is hangered, and the tanks are always refilled when I am done flying.

 

The plane goes to the mechanic tomorrow for a quick look to see if the fuel sender is leaking.  If that is not the cause, it looks like I might be in for a re-seal.  

 

Anyway, I'm planning on painting the plane soon.  Will a re-seal mess up a new paint job?  --It plays into the patch vs re-seal decision.  The current sealant is 32 years old

Chris,

 

Read this thread and coordinate reseal & paint with the vendors appropriately:

 

http://mooneyspace.com/topic/4581-where-to-get-fuel-leaks-fixed-on-the-west-coast/?hl=%2Breseal+%2Bpaint#entry58792

 

Dave

[carusoam]

Check your tank vents to make sure they are working.

Bugs have been reported to like them for nesting areas in many areas of the country.

Best regards,

-a-