So the summer started off with with decent cooling effect out of the A/C system. The previous owner had stated that they had replaced the refrigerant lines to the rear HVAC unit, but did not list when. Evidently they were either replaced some time ago or the replacement lines were a bit lacking in the quality department. A/C efficiency dropped once the weather started to get hot and it eventually required topping it off on a weekly basis to keep it cool. After a few cans of R134a, I decided it was time to find the leak and replace or repair it.
The leak was found on the larger refrigerant line where the line meets the mounting lug. Initially I was thinking it was a solder joint that was responsible for the seal. That was before I pulled the lines off. The mounting lug is soldered to the line, but that is not what seals the line. The line is flanged below the lug. The line itself was leaking just above the solder joint due to corrosion in the line that became visible only after I had cleaned up the line.
While soldering the leak would have worked with the proper equipment, I didn’t want to get it that hot. To use silver solder on the lines, I would have had to heat them to >500*F which I thought would result in damage to the rubber line about 6″ away from the affected area. I don’t have a cold sleeve to use that would protect the rubber line so I avoided that option.
A friend of mine that works in the maintenance department of a local college had suggested I try a product called RedEpoxY. For $16 and a little bit of time, I figured I’d give it a try. My other alternatives were to purchase a replacement line (>$400 – OUCH!) or purchase a block off kit for the suction/discharge lines under the hood which would eliminate the rear a/c all together (but leave the rear heat for the winter). The block off kit would have cost around $36. Time will tell if I made the right decision.
With the RedEpoxY, I preheated the affected area to ~200*F after disconnecting the line & thoroughly cleaning the area with a green scotch brite pad. I did a little cleaning with emery cloth right at the leak to remove the corrosion. The preheat allowed the epoxy to really flow well. I applied the epoxy all the way around the line at the mounting lug to seal/protect that whole area. After that, I heated the area to ~300*F to cure the epoxy.
After reconnecting the lines with new seals and torquing them in place (12ftlbs[144inlbs]), I then pulled a 30inHg vacuum on the system, leaving the pump on for 4 hours before turning it off to do a leak check. After ~24 hours of settling time, the vacuum had moved to 26inHg which is most likely due to moisture coming out of suspension in the system as well as some residual R134a coming out of the oil. That was enough proof that the leak was fixed. I then put the vacuum pump back on it and let it work over the next 12 hours to get as much of the moisture out of the system as I could.
The next morning I charged the system back up and it was throwing ice cubes!
