Hello all …
Does anyone happen to know the size of the nut (black arrow) that secures the low pressure a/c line to the expansion valve ?
I decided to do a routine check of the pressures on my a/c system and the low side service port (red arrow … horrible location) had somehow rotated counter clockwise up against the high side hose. Need to slightly loosen the nut to rotate it back so I can get to it.
Why not just select the correct flare nut wrench from your Metric and Imperial sets (hopefully Snap/on). 
I don’t remember all the sizes but it is METRIC.
You probably already know this but when twisting any of the nuts in the photo be sure you hold or brace the expansion valve so it does not move even slightly and screw up your evaporator,
Thanks all …
OK … removed the battery and tray (still not the best access) and as accurately as I could measure it. The nut is 23mm or just a little under 15/16". Can’t find a 23mm flare wrench so I bought a box end and I’ll cut and grind it down into a low profile flare.