Hitachi Zaxis 27U, 30U, 35U Excavator Service Repair Manual

Hitachi Zaxis 27U, 30U, 35U Excavator Manual:
Technical Manual: Vol No. T1LAE – 261 Pages
Workshop Manual: Vol No. W1LAE – 447 Pages
Hydraulic Schematics: 6 Pages
Hitachi Zaxis 27U, 30U, 35U Excavator Manual
Excavator Model: 27U, 27U-1, 30U, 30U-1, 35U, 35U-1
English

Manual Table of Content:

Workshop Manual Covers:
Safety
General Information
Upperstructure
Undercarriage
Front Attachment
Engine
Technical Manual Covers:
General
System
Component Operation
Operational Performance Test
Troubleshooting
Manual Extract: PARKING BRAKE
The parking brake is a wet-negative-type single disc brake which is released only when the brake release pressure oil is routed into the brake piston chamber.
When releasing the brake:

When the pilot control shut-off lever is in the UNLOCKED position, the pilot shut-off switch is ON. By this action, the pilot shut-off valve solenoid valve is ON, so that the brake release pressure (pilot pressure) is guided to the brake piston chamber to push the brake piston upward, allowing the brake piston and the disc plate contact to free which releases the brake.

When the brake is applied:
When the pilot control shut-off lever is in the LOCKED position, the pilot shut-off switch is OFF.
By this action, the pilot shut-off valve solenoid valve is OFF, so that the brake release pressure (pilot pressure) is not guided to the brake piston chamber.
The brake release pressure oil in brake piston chamber flows back to the hydraulic oil tank via the pilot shut-off valve solenoid valve.
Accordingly, by the spring, the brake piston gradually moves downward, allowing the brake piston to slowly come in contact with the disc plate to make the swing brake applies