Thanks. I read the manual and it says nothing about taking the port apart. I took the empty housing diving and the leak is definitely coming from the front of the lens port.
---------- Post added August 5th, 2014 at 04:28 PM ----------
Taking Steve's good advice, I took the lens port apart by removing the screws from the face plate which then lifts off. Under that is the glass face which is held in place and water sealed by an o-ring. Pressing the glass from the inside of the port pops it off. I cleaned the o-ring and all surfaces. To put it back together, grease the o-ring, put the o-ring into the port opening and then press the glass port into place. The face plate has a two little pegs that fit into holes and then the screws can be tightened. I'll test the housing tomorrow and see if it still leaks.
---------- Post added August 6th, 2014 at 01:56 PM ----------
It worked! I took the housing on a dive and it's dry.