HOUSING 9P9516 - Caterpillar

HMU Steering
Illustration 1 g03705039
Right Side View
Steering Components
(1) Metering unit
(2) Right turn stop
(3) Right neutralizer valve
(4) Steering control valve
(5) Right steering cylinder
(6) Steering pump
(7) Secondary steering pump
(8) Secondary steering relay
(9) Hydraulic oil tank
Illustration 2 g03707287
Right Side View
Steering Components
(1) Metering unit
(2) Right turn stop
(3) Right neutralizer valve
(4) Steering control valve
(5) Right steering cylinder
(6) Steering pump
(7) Secondary steering pump
(8) Secondary steering relay
(9) Hydraulic oil tank
(10) Secondary steering diverter valve
(11) Steering pressure sensor
(12) Secondary steering pressure sensor
(13) Left Steering cylinder
(14) Left neutralizer valve
(15) Left turn stopThe primary steering system is made up of two basic circuits. The two basic circuits are the pilot circuit and the high-pressure circuit. When a machine is equipped with the secondary steering attachment, the steering system includes one additional circuit.Pilot Circuit
The pilot circuit consists of the following components:
Hydraulic tank
Left turn neutralizer valve
Metering unit
Right turn neutralizer valve
Steering control valve
Steering pumpThe pilot system controls the movement of the selector spool and the directional spool in steering control valve (4). The selector and directional spools control the direction of oil flow in the high-pressure circuit.High-Pressure Circuit
The high-pressure circuit consists of the following components.
Left steering cylinder
Right steering cylinder
Steering control valve
Steering pumpThe high-pressure circuit provides the high-pressure oil to the steering cylinders to articulate, or turn, the machine.For further details of the steering system refer to Systems Operation, UENR 3110, "Steering Control".