COOLER GP-EXHAUST (NRS) 4355907 - Caterpillar

Illustration 3 g00275514
Cross-Sectional Views of the Manifold of the Levelling Valve (20) Passage. (21) Pilot pressure oil passage. (22) Spring for the accumulator valve stem. (23) Passage. (24) Accumulator valve stem. (25) Plug.
Illustration 4 g00275517
Solenoid Valve of the Cushion-Hitch (3) Solenoid valve. (26) Pressure. (27) Tank. (28) Pilot.
Illustration 5 g00284840
Components of the Cushion-Hitch (2) Manifold. (3) Solenoid valve. (29) Cushion-hitch accumulator. (30) Line to the head end of the load cylinder. (31) Line to the rod end of the load cylinder. (32) Levelling valve. (33) Line to the cushion-hitch accumulator.Levelling Stem
Levelling stem (4) has the following three positions:
Raise position
Neutral position
Lower positionWhen levelling stem (4) is in the raise position, the cushion-hitch is in the lockdown mode. When levelling stem (4) is in the neutral position, the cushion-hitch is in the cushion ride mode.The raise position of levelling stem (4) has a detent position. The neutral position of levelling stem (4) also has a detent position. The lower position of levelling stem (4) does not have a detent position.When the engine is first started, levelling stem (4) is in the raise position. Levelling stem (4) is in contact with manifold (2). Pressure oil from the cushion-hitch piston pump flows through check valve (1) into inlet passage (7) from the cushion-hitch piston pump. This hydraulic oil flows into passage (6) to cushion-hitch accumulator (29). This hydraulic oil also flows into passage (5) for the cushion-hitch piston pump oil for the pilot oil supply. The pressure oil flowing into passage (5) flows into manifold (2). Hydraulic oil pressure shifts accumulator valve stem (24) to the left. The shifting of accumulator valve stem (24) to the left shuts off cushion-hitch accumulator supply drain (11). When cushion-hitch accumulator supply drain (11) is shut off, the lower chamber of cushion-hitch accumulator (29) can fill with hydraulic oil. Hydraulic oil also flows to directional spool (12) .When levelling stem (4) is in the neutral position, the cushion-hitch piston pump oil flowing into inlet passage (7) is blocked from flowing into passage (6) to cushion-hitch accumulator (29). The hydraulic oil can flow back and forth between cushion-hitch accumulator (29) and the head end of the load cylinder.When a large shock occurs, levelling stem (4) moves to the lower position. Detent ball (8) is positioned on the bevel portion of levelling stem (4). Hydraulic oil is blocked in inlet passage (7) from the cushion-hitch piston pump. The hydraulic oil in passage (6) can flow through the notches on the upper portion of levelling stem (4). This hydraulic oil flows through outlet passage (14) to the hydraulic oil tank.Directional Spool
Directional spool (12) has two positions:
Lockdown
Cushion RideDirectional spool (12) is in the lockdown position in either of the following situations:
The engine was just started only a few moments ago.
The engine has been running for more than a few moments. The cushion-hitch switch is in the LOCKDOWN position.In both of these situations, there is no pilot oil pressure in pilot pressure