Have a '15 ML 350, a '15 ML 400 and a '08 ML 350 - all three are leaking R-134a refrigerant at the high pressure line Schrader valves. Have attempted to tighten the valves but the valves continue to leak.

Inspection of Mercedes' Electronic Parts Catalog - Group 83 (Heating and Ventilation), Subgroup 195 (Refrigerant line routing) - displays the high pressure line for these vehicles, as well as the high pressure port on the line. BUT... no Schrader valve replacement part is displayed for the port.

Inquired at my local Mercedes parts department and was advised no replacement valve insert is available because Mercedes wants the entire line replaced, not just the insert. Any truth to that statement? Line replacement is technically not difficult but space within the engine compartment is rather tight. Valve replacement alone would make life much easier.

Is a quality valve insert available from any other source??