I noticed some drips coming down from the bottom of my airplane this morning. It looked like oil, which was sort of suspicious since I just performed my annual. Taking a flashlight to the oil door showed no direct evidence of oil off the engine. My next thought is it could be some accumulated smoke oil that I may have been running rich. I got the creeper out and looked under the fuselage and notice there was no oil between the firewall and the main spar passthrough. The oil was coming out of the seam right under the main spar. And it had a blue-ish tint to it - must be fuel!
I removed the electric fuel pump/filter cover and it was quite apparent where the leak was - a small section of tubing between the fuel selector valve and the fuel filter. The fuel seemed to be originating on the connection to the fuel filter - this was a bit relieving because I just removed and cleaned the fuel filter for the recent annual.
Removing the section of tubing immediately revealed the culprit - the flare had fractured in two places.
I pulled apart the flare slightly to see how bad it was - and it was bad.
Here is the root cause of the issue - I overflared the tubing and it was catching in the threads of the AN fitting.
Here is the piece I needed to remake. Not the easiest part to make...
After a number of attempts, I made a new section of tubing which had proper flares on it.
Last Modified: August 13, 2023