Ok so here's a solution that worked (so far) for me.
Mine also had a pinhole leak at the apex of the low pressure line bend at the rear of the vehicle. I could see fixture marks on the line, it looks to have been poorly bent by the supplier resulting in a thinned flat spot on the 90-degree bend going to the rear unit. Definitely a stress riser there + thin material = not surprising it failed. I circled it in the photo below, this is from the rear of the vehicle on the driver side looking forwar.
View attachment 172245
Yes I was quoted $1400ish to have the rear subframe & fuel tank dropped and the line replaced all the way the front. On mine the rest of the line looks bright and clean, no corrosion to be concerned about there. I want rear A/C functionality so capping it off was out of the question.
Initially I called all the local a/c repair shops -- nobody could come up with a good way to cut, crimp, and splice a new piece onto my existing line. I found a longish flat/straight section on the line ~17" forward of the bend, loosened some of the clamps, and cut it with a rotary pipe cutter. It's 5/8" aluminum so it cuts pretty easily. I carefully deburred the inside and was careful so all the metallic shavings stayed outside the line.
My local hydraulic supply shop has tubing that size but they couldn't ultimately fab up something as they don't have the interfacing fitting to go to the rear condenser. They cut and welded a newly formed line to my fittings but couldn't get it to seal. Too bad, that would have been really inexpensive.
So, plan B:
https://www.amazon.com/gp/product/B0083H5ELM/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
Dorman makes what appears to be a knockoff of a GM compression service part for splicing A/C lines, this was ~$20. Make sure you get the 5/8" version if your low pressure line is leaking (model 800-640).
View attachment 172248
I ordered a replacement low pressure line from my dealer, it was ~$180 and luckily not backordered. It's pretty long so can be a pain to transport. I cut off the same length piece from the new line, installed it onto the vehicle with the Dorman compression splice, did an evacuation and it held a strong vacuum. I left it that way a couple of days to be sure. I then charged the system and it's been holding for 2-3 months now.
View attachment 172246 View attachment 172247
Will this work for you? I dunno, I am not an a/c expert. Everyone I talked to was shocked my '14 Explorer with ~100k miles had this failure....this is something they see on 15-year-old vehicles.
Best of luck whatever you try. Looking at the photo again I may go wrap that splice with some rubber hose to keep it from rubbing against the sister line....
