Tractor Repair: international 766, valve housing, control valve

Question
hello,when i start my tractor up after it sits overnight the power sterring dont work.the brakes dont work.and sometimes it will not move.but if it rus for a while everything starts working.changed filter still didnt fix problem.what do you think it is and if you know how do i go about fixing it.i live on a farm for 43 years so i do have experince with tractors but this  has got me.thanks tony.

Answer
  The brakes, steering, and TA all get their pressure from the same pump located inside the speed transmission behind the multiple control valve on the left side of the transmission.  The pump might be worn out or the oil might be draining out of the circuit because of a bad sump check valve.  The multiple control valve would have to be removed to fix either problem.  The sump check valve is a small plastic plunger with a spring that is located between the multiple control valve and the speed transmission housing.  The pump is mounted directly to the inside of the multiple control valve housing.