Thanks, although from the pictures it seems that they no longer have the sightglass. There are a couple on Amazon in the $30 range.

Where did you put your filter?

 

I installed mine just after the high pressure port line along the frame. If your rear A/C is still not working properly, the rear A/C filter in the liquid line may be plugged with crud as mine was when my compressor failed.

 

Just to help, here is a picture of the rear liquid line where the factory in-line filter (Marked by red square) goes.