Kobelco 27SR ACERA Tier 4 Excavator Service Manual

TABLE OF CONTENT

SAFETY AND GENERAL INFORMATION
MAINTENANCE
SYSTEMS
DISASSEMBLY AND ASSEMBLY
TROUBLESHOOTING
ENGINE

Preface Instructions

Read and understand all Warning plates and decal on the machine before Operating, Maintaining or Repairing this machine. The Manual has been written for the repair specialist. The serviceman or mechanic may be unfamiliar with many of the systems on this machine. This makes it important to use this manual and be caution when performing service work.

Please go carefully through the Shop Manual of the Excavator before starting any repair work. Use proper lifting procedures when removing any components. Be careful when removing filler caps, breathers and plugs on the machine. Hold a rag over the cap or plug to prevent being sprayed or splashed by liquids under pressure. The danger is even greater if the machine has just been stopped because fluids can be hot.

Use the Manual as a reference book and source of information even if you are familiar with Excavator technology. Using the Manual, the experience construction machine mechanic can carry out any necessary repairs expertly.

Sections of the Manual

How to Index each Service manual section. The General of his Service Manual consists of 8 heading as shown above. Each section can easily referred to by indexes appended to the margin of the page as indicated on the right.

SLEW OPERATING CIRCUIT
Pilot oil hydraulic system with operating lever Slew (Left) Operating Circuit
(1)Pilot Circuit
1. Slew Valve Spool Shifting
With operation for slew (left), the pilot secondary pressure oil is generated from the pilot valve (11), and led to the Pb2 port of control valve (2) to shift the slew valve spool.
2. Releasing Parking Brake
The pilot primary pressure is always led to PG port on the timer valve (303).
With the slew operation, the operating pilot secondary pressure is led to SH port on the timer valve (303) through the shuttle valve (15) to shift the spool.
It leads the pilot primary pressure 3.5 MPa (508 psi) to the parking brake to release it. (Similarly, the arm in operation releases the slew brake.) 3. Activating Parking Brake

When the slew operating lever is returned to neutral position to stop slewing, the pilot secondary pressure disappears causing to shift the timer valve (303), then the pressurized oil is shut down.
The oil in the brake cylinder is discharged due to spring force, and drained through the throttle in the timer valve (303).
Thus the braking is activated with some time lag for 2.5 to 5.0 seconds to smoothly absorb the slewing inertia at its stop of motion.

Identify the Tier Level of your Equipment (Read our Article on Tier Level )