The Port Tank over a longer period continued to leak at about 0.4 in/hr. There was still significant amounts of R-134A in the tank, so I theorized that the R134A was permeating the tank. The tank was purged with air until the detector barely registered any freon. The leak rate dropped to about 0.25 in/hr. Another theory was that the ground wire that was installed to ground the fuel cap to the engine ground was leaking through the cable. A quick soap and bubble test proved this to be true.
The cable was sealed by trimming some insulation near the penetration into the tank. The tank was pulled under a vacuum and epoxy pulled into the wire. The wire strands were pulled apart some and then it was filled with wet flox. It was completely covered with flox and a 1 BID was laid up over the wire.
After cure , the starboard tank did not show any significant leak. The ground wire on the Port tank was repaired in the same manner. The vent lines were tied together between the two tanks and pressured up. The leak rate was still 0.25 in/hr. Argh! Then I realized the R-134A had not been purged from the Port Tank. After the tank was purged of most of the R-134A, the pressure test held to 0.0008 in/hr over 4 days! The last pressure test held 44.5 in H2O from Sunday afternoon until Thursday evening. The tanks are successfully pressure tested.
