Oil leak behind the dash? It's probably the original copper oil pressure line that has a fracture in it and is leaking. Quite a common problem with the mechanical oil pressure gauges with copper 1/8" lines. This is our Nylon oil pressure line kit that replaces that leaky copper line. Vibration resistant Nylon. Comes with nuts and furrells to connect both ends from gauge to engine.  When restoring your Tractor, always change out the original copper oil pressure line with our new Nylon OPS kit.
 
B&B TECH TIP: Remember, this is a Nylon line. Keep this line away from exhaust manifolds or exhaust pipes. It can melt when near heat! 
Also, this is NOT to be used for a Traction Booster oil line! If you are missing or have a damaged Traction Booster oil line, replace it with a piece of 1/4" brake line tubing! Traction Booster lines can reach up to and between 3000-5000 PSI!