Use the same fittings the field repair technicians use when they charge you $350 for a service call!

What you will also want in your field repair toolbox (not included with kit!)

-1 pair of vice grip pliers
-2 medium sized adjustable wrenches
-Something to cut the bad line with... best thing you could have is a air die grinder with an air hose with glad hand fittings on the end so you can connect to your truck's air.
-Clean up rags
-Oil spill kit (yup, we sell those too!)

Guidelines:
Make sure you power down the pump before you start!
Cut hose in half about a half inch on either side of the leak.  (When joined together, the male and female JIC fittings will gain you approx 2 inches.)
The ferrules (collars) are reverse threaded, so LEFTY tighty.  Screw these all the way so the hose end comes up to the top of the wide part of the ferrule.