You'd need to replace the schrader valve completely.
can you block the high side on the ac on a car to stop a leak
You are on the wrong port. Some fords have an extra port that the low side hose screws on but is a high side fitting. look for another port.
The S port is the Suction and its the low side. The D stands for Discharge and its your high side.
Between the compressor and the washer fluid closer to the block is a blue cap low side. High is in front of grill.
The port next to the radiator is the low-side port
The 1986 Nissan King low side port can be found on the air conditioning compressor. The low side port will be labeled as the high pressure port.
It could be a freeze plug on the side of the engine block by the motor mount.
The port with the black cap on it is the low side as the red cap is the high side.
The small connector in the a/c line is the low port and the big connector is the high port side ...
Low side is the suction side and will have the larger hose attached to it and the high side is the discharge side and will have the smaller hose........
In my 2002 Tacoma SR5 V6 both the low side and high side ports are in the top, back, left corner (passenger's side) of the engine compartment. The low side port has a grey cap with the letter "L" on the top. The high side port has a black cap on it.
There is no high side service port only a low side.