TUBE A 7H1963 - Caterpillar

Illustration 1 g03321673
(1) Steering Hydraulic Tank
(2) Breather Relief Valve (Steering
(3) Metering Pump (HMU)
(4) Pump and Motor (Parking Brake Release, Prelubrication, Secondary Steering)
(5) Control Manifold (Steering)
(6) Pressure Sensor
Illustration 2 g03321756
(1) Steering Hydraulic Tank
(2) Breather Relief Valve (Steering Tank)
(3) Metering Pump (HMU)
(7) Piston Pump (Steering)
(8) Pump Control Valve (Pressure Flow Compensator)
Illustration 3 g03321777
(7) Piston Pump (Steering)
(8) Pump Control Valve (Pressure Flow Compensator)
(9) Position Sensor (Steering Cylinder)
(10) Steering Link
(11) Steering Cylinder The steering system is hydraulic. There is no mechanical connection between the steering wheel and steering cylinders that move the front wheels. The steering system is a closed center system. The steering system is independent of all other hydraulic systems. Oil for the steering system is stored in steering hydraulic tank.The primary steering pump is a pressure compensated piston pump. The steering piston pump is mounted to the right rear face of the flywheel housing. The primary steering pump is driven by the flywheel. The primary steering pump operates only when the engine is running. The output of the steering piston pump is controlled by a pressure and flow compensator valve. The metering pump receives signal oil from the pressure and flow compensator valve. The signal oil flows through a shuttle valve and to the steering metering pump. The signal oil determines the pressure and the flow of the steering piston pump. The pressure and flow compensator valve is fastened to the steering piston pump. The flow compensator valve in the pressure and flow compensator valve causes the steering piston pump to change from low pressure standby to full flow. The high-pressure cutoff valve limits the maximum steering pressure.Internal leakage from the primary steering pump is returned to steering hydraulic tank through the steering pump case drain filter. Return oil from the steering system flows through a steering oil filter. The steering system and steering pump case drain filters are located in the engine oil check compartment. Normally, oil flows through the steering oil filter and clean oil is returned to steering hydraulic tank.