Prior to first engine start in 2010, I used the electric pump to pressurize the fuel system and check for leaks ... other than a fitting near the flow meter the system was tight. Last week I had to replace the mechanical fuel pump (due to leakage from the weep holes) and to check the connections at the pump, pressurized the system with the electric pump. The pump connections were good but I noticed a leak at the banjo fitting. The source of the leak was the hose connection (fuel return to the tank) to the barb on the banjo fitting. I removed the firesleeve band and pushed the sleeve back. The hose had no clamp over the barb fitting. This hose makes a bend toward the firewall near the banjo fitting and I suspect that over time there was enough force on the barb connection to work it loose. An Oetiker clamp was added and the system now has no leaks. I do not know if the clamp on the banjo fitting was missed when the hose assembly was made or whether they never intended to used a clamp on the barb fitting. Going forward, I will periodiocally leak check this area using the electric pump and recommend others do the same.
Van's Air Force
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Fuel Leak at Banjo Fitting
- Thread starter rejnovca
- Start date
my .02 cents worth-
A barbd hose fitting has no business on a pressureized application on an aircraft. Period. Not sure who is making the hoses for Rotax, but I would hate to see someones hard work and money go down because a fuel hose pulled off a banjo fitting. Just ceause it has firesleeve on it, doesnt mean that the hose will pass a pressure test. If yours leaks, and no clamp, or crimp band on it, I'd personally would be looking for alternatives to what yo uare using.
Tom
A barbd hose fitting has no business on a pressureized application on an aircraft. Period. Not sure who is making the hoses for Rotax, but I would hate to see someones hard work and money go down because a fuel hose pulled off a banjo fitting. Just ceause it has firesleeve on it, doesnt mean that the hose will pass a pressure test. If yours leaks, and no clamp, or crimp band on it, I'd personally would be looking for alternatives to what yo uare using.
Tom
Fuel Leak at Banjo Fitting. I'm following the PAP (see p. G4-1) at this point and testing the fuel system for leaks. Everything looks good except I have a leak at the banjo bolt (M8x1x17, see 46-11 fig.2). It is torqued appropriately according to plans and verified in the Rotax illustrated parts manual. Neither the KAI nor the illustrated parts manual call for sealant, but I'm wondering if I should be using something like loctite 567?
Have others had leaks here and if so, what did you do to solve it? Thanks in advance for your suggestions. I'm going to go get a hamburger now. Slane
Have others had leaks here and if so, what did you do to solve it? Thanks in advance for your suggestions. I'm going to go get a hamburger now. Slane
I don't have access to the KAI right now but I assume you are talking about the banjo bolt for the fuel pressure/return line.
What can happen is the 2 banjo bolts can contact each other inside the block before the second one fully compresses the copper gaskets while being torqued. Rotax recommends that new gaskets always be used when assembling. They usually work for a second time but not always.
I wouldn't recommend using any sealant... new gaskets would be the right way to correct it. I guess another option would be to remove a small amount of material from the end of the bolt and try retorquing.
What can happen is the 2 banjo bolts can contact each other inside the block before the second one fully compresses the copper gaskets while being torqued. Rotax recommends that new gaskets always be used when assembling. They usually work for a second time but not always.
I wouldn't recommend using any sealant... new gaskets would be the right way to correct it. I guess another option would be to remove a small amount of material from the end of the bolt and try retorquing.
It is not a matter of elasticity, just that copper is soft so they get slightly thinner each time they are torqued. That is we Rotax specifies new gaskets be used each time.
Aircraft Specialty
Well Known Member
I have also heard of a few guys breaking the banjo bolt off. As a matter of fact, it happened to one of our customers.
If anyone is interested in getting away from the standard rotax hoses that recommend replacement at the 5 year mark, we would be happy to discuss other options.
We can offer a complete system retrofit replacement that converts the entire engine away from barbed fittings, and goes to a stainless steel AN type setup.
If you have any more questions, please feel free to email me at
[email protected]
There is also more information on our website.
If anyone is interested in getting away from the standard rotax hoses that recommend replacement at the 5 year mark, we would be happy to discuss other options.
We can offer a complete system retrofit replacement that converts the entire engine away from barbed fittings, and goes to a stainless steel AN type setup.
If you have any more questions, please feel free to email me at
[email protected]
There is also more information on our website.
RFSchaller
Well Known Member
I had to remove my return line once, and it only had the one clamp band on the outside of the fire sleeve.
I understand the concern about barbed fittings, but the system pressure is on about 5 psi which doesn't produce much pullout force.
I understand the concern about barbed fittings, but the system pressure is on about 5 psi which doesn't produce much pullout force.
