335F Excavator Machine Systems Caterpillar

Illustration 1	g03498302
Swing motor (1) Block (2) Swing motor (3) Anti-reaction valve (4) Anti-reaction valve (35) Fine swing solenoid valve

Illustration 2	g06008764
Fine swing solenoid valve (1) Block (8) Passage (9) Passage (10) Passage (31) Passage (35) Solenoid (36) Fine swing valve (37) Passage (38) Passage (39) Spool (40) Spring (41) Orifice (42) Orifice

Illustration 3	g02171595
The fine swing control switch is located on the right side control panel.

The fine swing control is installed to ensure an exact movement of the swing with minimal shock load. This function is done by equalizing the oil pressure in passage (8) and (10), creating a float swing behavior.

When fine swing solenoid (35) is de-energized, spool (39) is in the NEUTRAL position. Spool (39) is located in valve (36). The NEUTRAL position creates a closed connection between passages (37) and (38). In this position, the swing circuit operates in the normal manner.

When solenoid (35) is energized, spool (39) shifts downward against the force of spring (40). With the spool in this position, passage (8) is open to passage (10) through passages (37) and (38). Orifices (41) and (42) control the flow rate. Orifices (41) and (42) are located in block (1).

Note: When the fine swing control switch is ON and free swing is enabled, the swing brake solenoid is ON to release the swing brake.

Free Swing

Free swing control uses the same hardware components as fine swing control. This control allows for function similar to fine swing except that the control only functions during a swing operation. After the swing operation is complete, the swing brake solenoid is OFF to engage the swing brake.

When the fine swing system installation status is set to "Installed", the free swing enable status is set to "Enabled", and the fine swing control switch is ON the fine swing spool is energized. The swing brake solenoid is ON to release the swing brake.

When the fine swing system installation status is set to "Installed", and the free swing enable status is set to "Disabled", the fine swing spool is energized while the swing circuit is in operation. The swing brake will be OFF to engage the swing brake 6.5 seconds after the swing circuit lever is returned to neutral.