RETAINER 1283871 - Caterpillar

HOLD Position
When the lift or tilt control levers are in the HOLD position, there is no supply flow going towards the lift or tilt cylinders. In the HOLD there is no pilot pressure at the hose burst check valves (1) or (3) the valves remain in the closed position. With the lift or tilt in the HOLD position, the hose burst check valves (1) or (3) would prevent the lift arms or work tool from dropping at a high rate of speed.Raise Position
With the lift control in the RAISE position hydraulic oil flows through the main control valve to the head end of the lift cylinders. The oil flows through the lift hose burst check valves (3) to the head end of the lift cylinders. the cylinder extends. There is no pilot pressure acting on the lift hose burst control spool when in the RAISE position. During a failure of a lift hose, with the controls in the RAISE position, the lift hose burst check valves (3) closes and prevent the lift arms from dropping at a high rate of speed.LOWER or FLoat Postion
When the lift control lever is moved into the LOWER, or FLOAT position, there is pump supply flow going through the main control valve to the rod end of the lift cylinders. Lower pilot pressure coming from the main control valve, will flow through the pilot pressure resolver valve (5), through the pilot manifold (2) to the lift hose burst check valves (3) and will shift the lift hose burst control spool a proportional amount based on the lower command that