Sabretooth:
Sorry, I don’t quite understand, Why are you getting pressure when you connect the Suzzie? Yes there is always a little back pressure but if you pump the brake a couple of times prior to disconnect the pressure is released.
All the trailers I ever used had a handle at the base of the connectors in order to close the air lines. cutting off the air for disconnecting and reconnecting. Trailer braking systems have a one way valve system so the air is only coming from the unit air tank !! And once the handle is turned the air is closed off, so there should be no pressure building up or stored in the lines.
Plus allowing the air to flow while attempting to connect or disconnect is dangerous ?
Taps on airline suzies are banned by the UK Construction and Use Regulations. We don’t use palm couplings either. We use C couplings with non return valves and operating sleeves, either as an integral unit or assembled from the constituent components as shown.