PA18 fuel gauge leaking
- Thread starter cubnut93
- Start date
55-PA18A
SPONSOR
Dillingham, Alaska
You might need to make your own from a piece of cork gasket material. Not hard.
If you get the glass tube out, cleaning with an ultrasonic cleaner works great. Some Hoppe's No. 9 gun cleaner works good too. If you use any sealant or fuel lube on the gasket, be sure you don't close off the hole, or cause the float ball to stick. Also, check the ends of the glass tube for any chips. That might be causing the leak. Consider lining up a source of a new glass tube, as they sometimes don't like to be messed with.
Were you going to test it before hooking back up to the tank?
Jim
If you get the glass tube out, cleaning with an ultrasonic cleaner works great. Some Hoppe's No. 9 gun cleaner works good too. If you use any sealant or fuel lube on the gasket, be sure you don't close off the hole, or cause the float ball to stick. Also, check the ends of the glass tube for any chips. That might be causing the leak. Consider lining up a source of a new glass tube, as they sometimes don't like to be messed with.
Were you going to test it before hooking back up to the tank?
Jim
Last edited:
wireweinie
FOUNDER
Palmer, AK
Do you have a parts book?
Web
Web
The biggest issue is getting the gaskets to compress adequately while having the barbs pointing in the right direction.
thus the broken glass tube comment above.
EZ turn sealant, used judiciously, seals gaskets well.
Also, making your own cork gaskets of various thickness - doubling up on thinner material if needed - may help alignment as well.
to pressure test, cap one end put a hose on the other, submerge in water and blow.
you can generate a lot more pressure with your lips than the assembly will be subjected to in normal use.
ps: don’t get EZ turn on the little floating ball…
thus the broken glass tube comment above.
EZ turn sealant, used judiciously, seals gaskets well.
Also, making your own cork gaskets of various thickness - doubling up on thinner material if needed - may help alignment as well.
to pressure test, cap one end put a hose on the other, submerge in water and blow.
you can generate a lot more pressure with your lips than the assembly will be subjected to in normal use.
ps: don’t get EZ turn on the little floating ball…
Last edited:
cubnut93
Registered User
Thanks for the reply-
I have not heard any thing about "EZ turn sealant". I see that Aircraft Spruce stocks it. Sounds like it is similar to Sealube.
I have been using "Sealube" for several years and it has worked well for me. see photo.
The fittings that comprise the fuel gauge assembly do need to have some sort of sealer on them.
What is the best way to tighten the fittings so they line up and don't crush the cork gaskets?? Is it just a hit and miss situation?
I purchased a new bushing from Univair because the old one was showing it's age!
I assume that the upper fittings don't have much leakage unless the plane is doing acrobatics!? All the leaks that I have seen are at the bottom.
I have not heard any thing about "EZ turn sealant". I see that Aircraft Spruce stocks it. Sounds like it is similar to Sealube.
I have been using "Sealube" for several years and it has worked well for me. see photo.
The fittings that comprise the fuel gauge assembly do need to have some sort of sealer on them.
What is the best way to tighten the fittings so they line up and don't crush the cork gaskets?? Is it just a hit and miss situation?
I purchased a new bushing from Univair because the old one was showing it's age!
I assume that the upper fittings don't have much leakage unless the plane is doing acrobatics!? All the leaks that I have seen are at the bottom.
Attachments
Amy
SPONSOR
WI/MN/SD
Alternate solution: https://dakotacub.com/index.php?route=product/product&product_id=101
It has a straight fitting through the wing root so you don’t have to worry about having the fitting too tight (crushing the cork and splitting it) or too loose (not compressing the cork enough). The Dakota Cub gauge uses rubber-type o-rings to seal. I’m not sure of the exact material.
There is also a plug top and bottom that you can remove to clean the sight gauge glass.
It’s worth considering if you end up with a recurring problem. It was one of the first changes I made to my Cub. My only complaint is that, when flying a Super Cub with tanks in both wings, I would occasionally scrape my back on it but I can’t remember how I managed that.
—Amy
It has a straight fitting through the wing root so you don’t have to worry about having the fitting too tight (crushing the cork and splitting it) or too loose (not compressing the cork enough). The Dakota Cub gauge uses rubber-type o-rings to seal. I’m not sure of the exact material.
There is also a plug top and bottom that you can remove to clean the sight gauge glass.
It’s worth considering if you end up with a recurring problem. It was one of the first changes I made to my Cub. My only complaint is that, when flying a Super Cub with tanks in both wings, I would occasionally scrape my back on it but I can’t remember how I managed that.
—Amy
