Sonex Fuel Tank & Oops Fittings

[Concorde]

Are DCA's tools for fitting the OOPs fittings still available for loan?

Tom Jones
Onex 0133
Aerovee turbo

Tom, They are back in my tool box having done more traveling since Robbie had them. PM me with your shipping address and reimburse the $7 Priority Mail cost when you return them.

David A.

Hi David.
Do you still have the OOP's fitting tool .

[GordonTurner]

I too am ready to get in line for the tooling. Please PM me if you're last in line so i can give you my address. Thanks, Gordon

[DCASonex]

Oops fitting tools still here ready for their next tour of the country.

One of the previous users added a step drill ground down to proper size for drilling out the the small fitting making that a bit easier and cleaner.
PM me with your shipping address. If going to someone else before coming back here, put a few bucks in the box to pass along so that I eventually get my $7.40 Priority Mail cost back.

David A.

[Onex107]

In my Onex tank I put one OOPS fitting in the plugged hole. The plugged, unused hole, had an alum. plug in it and it leaked a little. When I tried to remove it the insert spun. The large molded in fitting is still working with the main shut off valve and filter, no problem.

[Concorde]

I used David's tool to install the Oops fitting and I replaced 4 of the fitting. It worked great ! Thanks David.
I shipped the tools to Gordon and they should be there by this Friday.
P.S. I also made my own 6061-T6 .90 washers and also used the Oring and used some grease between the bolts and the washers ,it worked great and they all passed the kerosene leak test .
If I had to do it again ,I would make the washers out of .25 or .30 Aluminum with the ID of 3/4" for small fitting and 1 1/4" ID for the large fitting and just simply use it to hold the Oring in place.

[rizzz]

Mine was perfect until recently, it started leaking from the big fitting. I have not touched the fittings since the initial installation.
Mine have not "spun" and were screwed in very carefully to absolute minimal torque (just a little more than hand tight).

The leak I have currently is very minimal, only a few drops over the course of a couple of weeks of standing in the hangar and it only seems to leak when we have really cold weather (not so much of a problem now).

I will probably attempt Phil Bird's fix first before installing an oops fitting, the fix is very easy to do and requires only a 3/16 plate, drilled and tapped to screw onto the AN fitting and some Permatex #3 to go between the plate and the tank.
But with the warmer weather we're starting do get here now the tank is fine, no leaks for the moment, so this will be a next winter job.

Well, the leak has gotten bad enough that I need to do something about it so I will attempt Phil's fix as mentioned above this weekend.
This should work as long as the molded fitting does not "spin" when removing the AN fitting. Fingers crossed.
Initially it was only the large molded fitting that was leaking a bit but now it seems small lower fitting that is used to attached the fuel sight gauge also has blue stains around it. I will need to do that one as well I'm afraid...

It is worth noting I have never removed the fittings after initial installation and they were fine for the first 50 hours or so. Goes to show that they can eventually start leaking even if left alone. This was just a bad design and it's a good thing Sonex has abandoned these molded fittings now, unfortunately for me I already had my tank installed when they did...

[DCASonex]

Welcome to the club. My molded in fittings were also good for about a year, then started leaking for no obvious reason.

Looking at how to install the oops fitting in a tank in the plane is what lead to developing those oops fitting tools.

David A.

[Waiex 49]

Michael,

Sorry to hear about your issues with the fuel fittings.
Been there, done that, got the scars to prove it.

If you have to remove the tank from the plane to do the "oops" fittings, I would suggest a method easier than the Sonex "approved" method for tank removal and installation.

Drill out the rivets and remove the screws that secure the left and right side rudder assembly support brackets. Real easy to do, the screws and rivets are on the outside of the fuselage sides. This allows you to drop the complete rudder pedal assembly down to the floor. With the rudder pedal assembly out of the way it is very simple and easy to remove and reinstall the fuel tank.

The Sonex "instructions" for removing and replacing the fuel tank completely suck, in my humble opinion.

Best of luck to both of you in your efforts to fix these leaking fittings. The real "oops" is Sonex's poor original design on these fittings.

Don

[rizzz]

Drill out the rivets and remove the screws that secure the left and right side rudder assembly support brackets. Real easy to do, the screws and rivets are on the outside of the fuselage sides. This allows you to drop the complete rudder pedal assembly down to the floor. With the rudder pedal assembly out of the way it is very simple and easy to remove and reinstall the fuel tank.

Hi Don,
Thanks for the tip. Unfortunately this would only work on a polished Sonex.
Mine is painted so drilling out/removing any external rivets/bolts will destroy the paint job in that area...
Good idea though.

[rizzz]

I went to the airport today and did the fix as described before, some pictures:





I don't know if this will work yet, I'll leave it overnight to cure (even though the Permatex #3 does not really "cure") and put some fuel in tomorrow.
I'll report back when I do.