If thats the case the main system relief becomes a potential point of failure.OK You can do the same thing by teeing into the PB at the loader valve. Then disconnect the quick disconnects on the hoses that connect to the backhoe. There are check valves in those disconnects, so this will have the same effect as capping the tee on your test gauge. See what pressure you get, don't run it too long.
Note to @TheOldHokie: the L35 loader valve doesn't have a relief valve. The system relief is back near the lift cylinder, I think, in the line before it gets to the loader valve.
If you are sure of that things are even easier. He can connect the gauge to the end of the P supply and read relief pressure there. That completely eliminates the loader and 3pt.
Dan



