I have a 222RE with R12 system. My problem is my R12 manifold gauge set will not fit the high side valve up near the firewall. It's a smaller valve than the connector on the gauge set. I need to pull a vacuum, then add some dye so I can find my leak and I prefer to have both gauges connected so I can see what pressures I have on both sides. Any suggestions besides taking to a shop would be helpful.
Maybe I'm wrong here but R12 uses screw on Schrader valves and R134a uses stc (snap to connect) Schrader valves. So I know it hasn't been converted. However, it appears the Schrader valves on my truck are different sizes. If my research is correct the low side is 1/4 and the high side is 3/16. I don't recall this being the case in my old Mustangs but I haven't had to charge an ac system in any of my 67 Mustangs in many years now. Could be I simply lost the reducer fitting to my manifold gauge set. Anyway, thanks for your reply!
