Fuel check valve question

[Paul DAnneo]

Hello All,
   
  Quick inquiry.
   
  Seems my fuel pump internal check valve isn't "checking". Aftermarket Pierburg pump and I'm looking into installing an inline check valve. 
  Since mine is still in the tank, maybe someone knows the pitch and diameter of the outlet nipple banjo fitting. I ordered a check valve, but its for the stock pump and is too small, as is my brain and I didn't measure it before re-installing the pump.
   
  Otherwise if there is a proven effective way to "inline it", I'd love to hear about it.
   
  Also, since you're all here, is there a write up on the repair of the speedo/ odo repair?
   
  Any and all answers are greatly appreciated.
   
  Paul