Tractor Repair: 464 IH Hydraulics, center bolt, rubber gasket

Question
After changing hydraulic fluid and filter on a 1976 IH 464 the hydraulics and power steering won't work.The fluid is about 1/2" over full mark but the pump apparently won't pick up the fluid.
Is there a way to prime the pump or remove an airlock.The pump appears to be internal. I am at a loss.Everything worked fine before servicing. Your help greatly appreciated.

Answer
Hello,

  It sounds like you have a suction leak after changing the filter.  Check that the filter canister is sealing onto the rubber gasket properly, and that the sealing washer around the center bolt is in place  It is easy to get the canister slightly off center when installing it which will create a suction leak.  It should prime by itself, there is no priming procedure.