Tractor Repair: 856 IH steering loss, torque amplifier, control sector

Question
Greetings - and THANK-YOU!
My friend has an IH 856, owned since new in 1969 (I think). Recently there is a complete loss of power steering - steering of any sort actually.  The steering wheel can be turned with absolutely no result.  There is also essentially no brakes, but the remote hydraulics seem to be OK There is no 3 point. Is there a port somewhere to check hydraulic pressure at the steering control sector?  The steering pump was removed, no obvious signs of failure.  I am suspicious of some sort of routing valve or perhaps a relief valve that failed. We both have overhauled engines, minor gear case work, etc., but have little experience with hydraulic systems.  Are you familiar with a common cause of the no steering syndrome?  We appreciate your thoughts....dave

Answer
Hello,


  The steering, brakes, and torque amplifier are supplied by the front pump located behind the multiple control valve on the side of the speed transmission.  The remotes and hitch are supplied by the rear pump just in front of the rear axle housing.  There is a steering relief valve, steering priority spool, and sump check valve that can all affect the steering and they are located in the multiple control valve.  Sometimes the gasket or o-ring between the multiple control valve and the speed transmission housing blows out, sometimes the pump fails, sometimes a spool sticks or a spool return spring breaks, or the orifice in the priority spool plugs up.  I believe there is a port on the multiple control valve where a gauge or flowmeter can be hooked up.

                            Good luck,

                                Arnie