The Navion N5210K restoration project commenced in 2005. The main impetus for my restoration effort was the discovery of two large holes cut into the floor to fix leaks in the Navion’s main fuel tanks.

Repairing the holes someone cut decades earlier into the wings involved the demating of the fuselage from the wings, then splitting the wings into two halves to gain access to the fuel tanks that were the root of the problem. Both fuel tanks leaked (as all original Navion tanks did over time), and were replaced with refurbished tanks from Sierra Hotel Aero.

While the wings were off the fuselage and split apart, it was prudent to make improvements in other areas of the inside of the wings and fuselage. The following are notes of what I found and what was performed.

The fuselage was hoisted way up in the air after being demated from the wing, exposing the area under the floor of the cockpit and the rear of the nose gear wheel well. 55 year old dirt -- more than an INCH thick in some places -- was found under the floor and in the wings that had to be painstakingly cleaned out of hard-to-reach areas. 

Once it was thoroughly cleaned inside the wing, zinc chromate primer was applied to the area to protect the aluminum for another 55 years.

The joined wing was split into its left and right halves, to gain access to the fuel tanks. Once the tanks were out, it was clear to see where they had been leaking; the leaks left a burgundy/brown residue that had to be steam cleaned out. Also, there was much more dirt in both wings, which, added to the dirt from under the floor of the cabin, weighed three pounds!

Deep up in the wheel wells, dirt was encrusted around all kinds of parts: wiring, hoses, clamps, fittings, brackets, gear legs...everything. So more steam cleaning and scraping was needed to get it all out. In the process, the paint -- which had been sprayed on top of old dirt and paint without proper preparation -- came off. I made the decision to scrape and steam it all down to bare metal and do it properly.

In the process of steam cleaning the main gear wheel wells, a significant part of the paint under the wings (which are polished on top, painted on bottom) practically fell off in newspaper-sized sheets. So again, to do it right, I made the decision to strip the wings and the underside surfaces of the ailerons and flaps to bare metal, and repaint them from tip to tip in a bright metallic silver. That meant losing one of the "Stars & Bars" insignia painted on the right wing, to be repainted after the wing has been painted.

While the wings were being repainted, the gear doors, gear legs, wheels, flap and aileron brackets, hydraulic lines, switches, old wiring, brackets, extender tubes, pullies, cables, everything  in the main gear well wells was removed.

The rubber hydraulic lines and wiring were discarded for new materials. The remaining parts were then steam cleaned, scraped, steam cleaned again, then sanded and "Scotchbrited" to prepare all the surfaces (including the surfaces of the removed parts and inside-the-wing surfaces) for priming and painting.

Note: The original hardware, some of which was badly corroded, was replaced with parts provided by DeLuca of California.

The six steel aileron cables were replaced with stainless steel cables, eliminating an Airworthiness Directive on the old cables. 

Note: The condition of the rudder cables was excellent; the cables were deemed airworthy.

A beef-up kit and hatbox kit from DeLuca was installed into the fuselage, thus preparing the airplane for a larger engine in the future, and making the airplane stronger in general. This effectively took the fuselage of my Navion from a Model A (1950) to the more popular Model B (1951+), which can handle a bigger engine without further modification to the airframe.

The two gas tanks in the wings were replaced with factory refurbished tanks, with new rubber fuel lines. A larger accumulator tank was installed (replacing the original one) to accommodate the higher fuel flow rate of a future larger engine.

DeLuca's improved leading edge air intake vent system was installed at this time, to put some cooling air into the cockpit for hot days.

Additional wires were run to each wing tip for fuel sending units, to be installed into future wing- tip tanks.

The O-rings in the two main gear actuators were replaced, since they were weeping slightly.

The two main gear actuator shafts were replaced, since the original ones were made of thinner tubing. Replacing them eliminated an inspection Airworthiness Directive.

Note: Upon inspection of the trunnions in the main landing gear, both sides found to be tight and not in need of replacement, and so were deemed airworthy.

The ancient brake lines were replaced with steel braided lines.

The nose gear was disassembled, stripped of paint (as applicable), cleaned, inspected, and parts were replaced as necessary. The parts were then prepared for the application of primer and paint, then were reassembled with a new strut seal kit from DeLuca.