After successful compressor replacement and refrigerant swap, from R134a replacement with (40%) proprietary R290/R600a blend, we have discovered that both service valves are leaking.
Renewing both schrader valves, within the push-fit service valve fittings, did not seem to help. Over-tightening the schrader valves improved the situation significantly, however a very slow leak remained.
Unfortunately the push-fit service valve caps are plastic, with a thread matching the schrader valve, and do not hold (much) pressure.
Any advice on the best way forward would be warmly welcomed.