Bmw4u

When I bought the car was already with a/c leak , that was re filled with FREON JUST TO BE SELL,
now " is my problem,"
who knows for how long they were doing that, all air inside the system, may or may not mess up
now i trying to replace the receiver dryer
i found it on the condenser attached, but how do open to removed and replace the dryer inside,
from the bottom i will have to removed the low and high lines , AND THEY ARE SUOER STUCK, i been see in videos that the break the" pin" when replacement of the condensor, but they do not care because has a leak my has not only the compresor
With cover


Is the only thing , like a screw, i though was a reteiner clip, cause has one holding the dryer insude the tube , but is not a clip

From the side , i do not see any separation from the top, why is a cover?

Bmw4u

any knowledge will be very help full, thank you in advance.