Fuel Caps and other parts for M20C

[Urs_Wildermuth]

Hi all,

during my annual, it has come out that I will need new fuel caps as well as a cable assembly for the trim indicator for my M20C.

Has anyone got any good source where I could find these?

one piece PN 740019, Cable Assy Trim Indicator

2 each: Fuel caps Shaw Aerodevices, Part Nr 431-9

Any ideas are very much appreciated.

 

On the similar topic: I recall that some company once made two caps which fit over the existing fuel caps, preventing water leakage.

http://www.staysealed.com/flushcartdisabled.html

But these are discontinued. Has anyone got a pair of these around for which he doesn't have a use anymore? I've been looking for them for a while.

 

In recent months, I had two instances where a good gallon of water sept into the tanks after rain. Something needs to be done here.

 

Airplane is a 1965 M20C, SN 3269

 

Many thanks

Urs

[Andy95W]

Fuel caps are really expensive.  If they are only letting water in, you probably just need 2 o-rings for each.  Those are recommended to be replaced every year.

[Urs_Wildermuth]

We have done that every year and every year they leak again. We found that they have quite a bit of wear and tear. And what does "Really" mean in terms of expensive? Having the engine cleaned out because of water or, heaven forbid, loosing the engine because it quits in the air after switching tanks is also not cheap......

We had it twice last year that there was so much water in, that it was not visible proper when draining the tank.. (over a gallon... each side) and when they tried to start the engine, it sucked the water in. VERY expensive to rectify each time.

[cliffy]

I can understand your concern. I'm just wondering where the extreme wear is on the caps. Just to be perfectly clear, you say you replaced both orings in each cap (2 orings per cap, 1 large and 1 small) and readjusted the the top lever closing(if it has a nut on the bottom) to get a good tight  seal on the tank ring?  Did you clean and check the tank ring ? Is there rust or a rough surface where the large oring sits on the tank steel ring?

Is the cap physically tight in the tank hole when you close the lever?

Can you post a picture of the caps top and bottom? 

Did all this water come in in one rain storm or did it happen over a long period of time between flights? ? 

Just trying to understand the issues as I've never seen one that was "worn" to the point it couldn't be fixed to function correctly. 

 

[Urs_Wildermuth]

Cliffy,

I'll try to get some pics.

We found that the rim of the top part,where the large o-ring goes, has some holes below the ring. Also the lever is badly deteriorated. The lower part, which has the writing on it, appears ok. It appears closed when the lever is shut, it requires quite some physical force to close and open. The tank ring was checked and cleaned last year, it is totally rusty now as it was before we cleaned it last year.

We re-did the o-rings on last annual (a year ago) and for a while the problem was better, not gone though. It appears to me that the new o-rings usually cure the problem for a few months, but maybe less than half a year. Obviously here there is a LOT of rain, there is hardly one week without it.

Twice, after intensive rain, the quantities of water in the fuel was such, that it was no longer reckognizable at first when draining, I'd estimate more than one gallon in one tank, about half a gallon in the other.

My maintenance thinks that the water gets in through the middle of the cap, not through the side. There is however standing water every time it rains, that is why I want to cover them with the now extinct caps by "staysealed" but apparently they are totally out of production and out of reach. We have to find a way to put a cover over the caps, otherwise we don't know what to do.

I think that at least the levers need replacing, better the whole cap.

 

[ELT]

The stay sealed covers were junk.  Blew off on first use.

[DonMuncy]

I have a pair of gas cap covers once offered by the "Mooney Miser". They are not useable during flight, but I don't think they would blow off while on the ground. If these hold any interest for you, I will give you the information. they should be very easy to duplicate.

[smwash02]

I had the same problem. I spent a lot of time adjusting the spring, but ultimately it would still leak.

I ultimately bought 2-3 on ebay and found some that worked out for me. I have since learned you can clean up the bottom of the tab you flip up and down and that will help it seal up. I plan to see if I can repair my old ones at some point.

My SN is close to you - 3231. Not sure what your budget is, but the ones I found were 60-80 shipped each.

[carusoam]

I bought a set for my C from my MSC.  Expensive is a couple hundred USD each I think...

having the exact part number helps if you want to go EBay.  There are a few companies that specialize in used ones.

the fuel neck or the receiver for the cap may have been changed along the way.  Often that original part rusts away allowing water to ingress into the tank.

Check to see if your fuel neck is SS before buying a cap for an outdated receiver.

Best regards,

-a-

[Yetti]

There are 3 o-ring per side.  Two of them are 010 and seal the shaft.  Then an 338 for the outer ring.

The shaft of the lever is steel so some emery cloth can clean that up.

I used Jet Lube to keep things smooth

They should not be hard to open.

They are easy to service.

http://www.amazon.com/gp/product/B00138384I?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01

 

 http://www.amazon.com/gp/product/B0055E1RLM?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01

 

http://www.amazon.com/gp/product/B009CFNL46?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

 

 

[Yetti]

There are a fair amount of caps for sale on flea bay

[neilpilot]

7 hours ago, Urs_Wildermuth said:

We had it twice last year that there was so much water in, that it was not visible proper when draining the tank.. (over a gallon... each side) and when they tried to start the engine, it sucked the water in. VERY expensive to rectify each time.

Hi Urs,

I do agree that you want caps that seal properly, but I also find it somewhat surprising that you attribute a leaking fuel cap to the accumulation of a gallon of water.  If you leave the cap completely off, that results in an opening of approximately 3.5" diameter (maybe a bit more).  Not doubting your data, but it would require a 24" column of rain to pass 1 gallon through a 3.5" opening.  Please check my math on this.

Have your fuel tanks ever been repaired, or do you have bladders?  If, for example, fuel equalization holes in the wing ribs are blocked with sealer during repair or relining, as I understand it water is not free to drain toward the wing sump and a surprising amount of water can accumulate in the wings over time.  This could present a real problem irrespective of the condition of your caps.

[Guest]

9 hours ago, Urs_Wildermuth said:

Hi all,

during my annual, it has come out that I will need new fuel caps as well as a cable assembly for the trim indicator for my M20C.

Has anyone got any good source where I could find these?

one piece PN 740019, Cable Assy Trim Indicator

2 each: Fuel caps Shaw Aerodevices, Part Nr 431-9

Any ideas are very much appreciated.

 

On the similar topic: I recall that some company once made two caps which fit over the existing fuel caps, preventing water leakage.

http://www.staysealed.com/flushcartdisabled.html

But these are discontinued. Has anyone got a pair of these around for which he doesn't have a use anymore? I've been looking for them for a while.

 

In recent months, I had two instances where a good gallon of water sept into the tanks after rain. Something needs to be done here.

 

Airplane is a 1965 M20C, SN 3269

 

Many thanks

Urs

Search for Mooney SB M20-229A. It explains the fuel cap.  If you want to find your leaks first, connect a long piece of surgical rubber hose to the fuel vent under the wing.  With your mouth blow into the hose, you will see the wing skins bulge a bit.  Pinch the hose, then spray soap and water on the cap.  The leak should be very clear.  Fix as required

Clarence 

[carusoam]

Neil makes an interesting point.

My C collected water around it's cap in a large amount.  I think there is a larger amount of water that runs down the wing and into the tank if there is a way to get past the seal.  Kind of like a large funnel.

Best regards,

-a-

[Jim Peace]

Try this place for the fuel caps.  I think I bought my Shaws there:

 

https://www.preferredairparts.com

[Urs_Wildermuth]

Thanks for all the comments.

We found that apparently the problem is in the actual filler. It is pretty badly corroded. We have tried to locate the parts, but so far were not able to. Comment we got from one of the German MSC's is that Mooney does not support the "C" Model anymore. So I wonder what to do. We need to exchange the filler plates in order to stop the leak, moreover, we need to get rid of the corrosion in there if we can't. The actual caps may not even be the problem.

I've written to Don Maxwell and I hope he can come up with some source for these parts.

[carusoam]

Take a look at the alternatives...

The O's gas tank fill parts start with a standard access panel.

a SS fill neck is sealed and riveted in place in the access panel.  The C's original mild steel fuel neck rusts through where the stress from the original forming of the parts has changed the metal's structure.

The O's cap fits in the fuel neck.

Does the C have a different access panel than the O?  I wouldn't think so.

But I know a person who does...

Sherry at LASAR is your GOTO person for the answer.

She has no problem shipping international.

Send an email to part-mods@lasar.com

Dr. Don is surely a GOTO guy as well!

I find it unlikely that Mooney does not support the C anymore.  For that, contact the factory directly.

Let us know if you can't get support for the nicest C flying in Europe.

Best regards,

-a-

 

[Urs_Wildermuth]

Thanks. Will try those avenues and let you guys know what transpired.

 

 

[carusoam]

Urs,

The old mild steal fuel necks went through a wave of replacements around 10 years ago.  There are probably enough parts on an MSC shelf somewhere...

Expect that it is near a 1AMU job for each side that doesn't make anyone happy.

My C moved on needing those parts, paint, and engine mount and other things...the new caps I bought didn't fit in the old necks as expected.  I gave the new caps to the new owner as a parting gift...

Hope that helps,

-a-

[Urs_Wildermuth]

Carusoam

 

do you mean the necks themselfs can be replaced separately from the whole neck+plate?

Looking at the caps, I think they are re-usable. It is the necks which are toast and need to be replaced. By the looks of it, we are even AOG until then.

Where did you get yours? Is there a part number I should ask for (as you say they are of a different material than the "mild" ones)?

[carusoam]

Urs,

there are Three parts...

1) Top access panel. Flat oval or rectangle with rounded ends.  I expect that your access panel is still usable. This will keep from Major reseal issues.

2) Fuel neck. The original pressed 3D shaped fuel neck is made from some mild steel back in the day when they thought planes would be scrapped like automobiles, every five years.  Drilling out the old one and reinstalling with sealant and new rivets should be all it takes.

3) Fuel cap.  I had some plastic race car caps that had been installed.  When I bought replacement caps, the shaw replacements did not orient properly.  It was probably a simple disassemble and reassemble properly but I never got that far.  The tabs were not aligned with the airflow over the wing...  This is where I realized that it wasn't a cap issue as much as a rusted fuel neck problem.  The plastic caps looked identical to the aluminum ones.  The plastic cap supplier wouldn't sell me one when I told them what it was for.  They used to supply to aviation but not any longer....as if race cars were more gentle.

Getting / identifying the correct parts should be as simple as knowing the diameter of the hole in the top access panel and the proper number of bolt holes that it has.

I am pretty sure I bought my parts from Sherry.  She was always helpful for me to get parts for my C.  They are an MSC that likes to support the older birds including making some parts and refurbishing others.

there is probably a service bulletin for this since the wave of replacement did happen...

Sherry has been known to visit MS.  You may want to copy this thread's URL in your email to her..?

Best regards,

-a-

 

 

 

[Urs_Wildermuth]

Understood, thanks.

[Urs_Wildermuth]

An update on this.

I did get in touch with Don Maxwell and he could not have been more helpful. We got all the parts here and are currently installing the new fuel caps and aileron rods. Hope to be airborne again in about a weeks time.

It's great to have people like you guys here at Mooneyspace and real pros like Don around to help when things do get a bit more complex.

Thanks to all of you for your help and especcially to Don for organizing and shipping all the necessary items.

[63C]

10 hours ago, Urs_Wildermuth said:

An update on this.

I did get in touch with Don Maxwell and he could not have been more helpful. We got all the parts here and are currently installing the new fuel caps and aileron rods. Hope to be airborne again in about a weeks time.

It's great to have people like you guys here at Mooneyspace and real pros like Don around to help when things do get a bit more complex.

Thanks to all of you for your help and especcially to Don for organizing and shipping all the necessary items.

Don is great to work with. Will usually go out of his way to get you what you need.

[philipneeper]

You could also use Parkers O Ring jelly, comes in a yellow and black tube. Apply that to the O rings and the mating surface. It doest get a little sticky but clears a seal and you won't have to worry about water