814F Series 2 Wheel Dozer, 815F Series 2 Soil Compactor and 816F Series 2 Landfill Compactor Steering System Caterpillar

Illustration 1	g01287621
Steering hydraulic system schematic (1) Oil cooler (2) Steering metering pump (3) Steering pilot return line (4) Right steering cylinder (5) Left steering cylinder (6) Steering control valve (7) Valve spool (8) Pilot section (9) Implement section (10) Steering pump section (11) Pump group (12) Filter group (13) Hydraulic tank (14) Steering pilot pressure reducing valve (15) Right neutralizer valve (16) Left neutralizer valve (A) Implement system (B) Brake system (C) Implement pilot system

Illustration 2	g00876136

Steering pilot pressure reducing valve (14) is on the top left side of the engine firewall.

Illustration 3	g01256678
(14) Steering pilot pressure reducing valve (17) Pressure inlet (18) Drain outlet (19) Reduced pressure outlet

A part of the oil from pilot pump (8) flows to the brake system. The rest of the oil flows into inlet (18) of the steering pilot pressure reducing valve (14).

Oil flows through inlet (18) into steering pilot pressure reducing valve (14). Steering pilot pressure reducing valve (14) is a cartridge valve. The steering pilot pressure reducing valve reduces the pilot pressure for both pilot and steering circuits. The pilot pressure is reduced to 2896 ± 138 kPa (420 ± 20 psi).

Reduced oil pressure flows through reduced pressure outlet (19), then to the pressure control valve and the selector valve for the implement system. The oil continues on to the steering metering pump (2). Excess oil returns to the hydraulic tank through drain outlet (17).

Oil flows from the steering pilot pressure reducing valve into steering metering pump (2). The steering metering pump is attached to the steering wheel. As the steering wheel turns pilot oil flows through the steering metering pump to either left neutralizer valve (16) or right neutralizer valve (15).

Pilot oil flows from the neutralizer valves to steering control valve (6). The pilot oil pushes one side or the other side of control valve spool (7). When the spool moves, high-pressure oil from steering pump section (10) flows to right steering cylinder (4) and left steering cylinder (5).

Return pilot oil from the steering control valve and the neutralizer valves flow through steering pilot return line (3) back to hydraulic tank (13).