Your system has a orifice tube, not an expansion valve. The high and low schrader valves are replaceable. The large low side fitting that looks like a small black ball inside is all one piece. You will need a special socket to remove it. Pliers can be used but it will tear up the aluminum. Replace the high and low and get it recharged.

 

This recharging business is getting expensive

I have a valve stem remover and tightened it a little since ive read that it sometimes loosens up and leaks. Im hoping that fixes it.

thanks for the help