"Dead Easy" pump, fittings thread

[Des28Qau]

Hi Guys,
Has anyone reconditioned or have, a dead easy air pump ? and the ability to identify the thread used for the air fittings ? And is the top fittings thread the same as the link pipe/tube thread?
I have just cleaned up an shabby looking pump , greased up the leathers and joints, cleaned up and painted the castings , polished the cylinders and cleaned up the check-valves & bolts, then rebuilt. On testing I find the balance pipe/tube cracked was (not desturbed) and is leaking .
I have taken the top castings to a local pipe hose & fitting (mostly hydraulics) shop, but they could not match.
If I can match (prefered) the thread great or I will just have to tap the castings M6 or 1/8npt or what ever can work for me.
Thanks in anticipation .
Regards Des.