Most likely internal failure in the pump. From what I've read, the valve assembly on top prioritizes flow to the hydro 1st, steering 2nd, then FEL/3pt last. If the pump begins to lose pressure, the FEL/3pt operation will be affected first. No idea what the ball bearing is from, but every pump failure/removal I've read mentions it falling out.
How many hours on tractor, hydro fluid? What brand of fluid are you using?