I have modified standard power steering pumps with the fill cap in the sheet metal housing for an external reservoir by cutting the tapered section away and soldering a piece of sheet metal on to make the thing round. Since the housing carries no pressure, lead/tin acid core solder like a radiator shop or a HVAC shop uses and a Propane torch is all that's needed to attach the modified reservoir.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!