UH-1 Hydraulic Lines
Over the years Hydraulic lines and fittings in the Huey have been changed, chaffed, removed and reinstalled, even become bent over time. Basically all these fittings and lines are of MS flair-less design.
These work well if initially installed properly and not disturbed.
If installed properly the line will be of a length to fit perfectly seated in to the two fittings.
To remove a line between two fittings you have to slightly bend the line so it can be removed.
The problem comes when reinstalling the line, you have to install it with the bend then straighten the bend perfectly to reseat the line ends in the fittings.
If the angle is off even a couple of degrees the line will leak.
MS fittings are easy to over torque and cause cracks in the fittings. With AN fittings, because of their design, you can tighten them a little more and get a seal.
After an MS fitting and line are assembled once the crush fit is established and tightened even more only cracks the fitting.
A number of operators have had this problem and found a fix by using flex lines in place of the hard lines.
Over tightening these can still crack the fittings, but connection alignment is much easier and instead of crushing a sleeve onto the line.
The proper fit is built into the end fitting of the line.
The flex line can be used to reroute the line for a better fit.
See example pictures in article.