why did you file the Endcap? What part didnt fit?
Also someone on the forum posted that he used a Rubber coupling on his co-axial same design minus the Sprinkler valve.
EDIT:
Just took a closer look. You are probably loosing some air through the bolt? If so JB Weld or maybe a glue gun will help.
Second: what did you use as supporters for the 2" pipe in the chamber?
