320B Excavator Hydraulic System Caterpillar

Note: The engine speed and/or the machine configuration that is used during this test can affect the results of this test. Refer to Testing and Adjusting, "Operational Checks" for the engine speed and the machine configurations that were used for this test.

Note: The relief valve pressure settings must be set to the relief valve pressure specification before performing this operational check. Refer to Testing and Adjusting, "Pressure Specifications".

Table 1

Required Tools
Part Number	Description	Qty
5P-3277	Measuring Tape	1
	Stopwatch	1

Illustration 1	g00298378

1. Position the machine on level ground. Refer to Illustration 1.

2. Empty the bucket.

3. Raise the boom until the top stick pin is the same height as the boom foot pin.

4. Fully extend the bucket cylinder.

5. Fully retract the stick cylinder.

6. Extend the stick cylinder rod 70 mm (2.8 inch) from the fully retracted position.

7. Measure each cylinder's length from cylinder pin to cylinder pin.

8. Stop the engine.

9. Leave the machine in this position for five minutes. Measure each cylinder's length from cylinder pin to cylinder pin for drift.

Table 2

Cylinder Drift (Empty Bucket)
Item	New	Rebuild	Service Limit
Boom Cylinder	6.0 mm (0.24 inch) or less	12.0 mm (0.47 inch) or less	24.0 mm (0.94 inch) or less
Stick Cylinder	10.0 mm ( 0.39 inch) or less	15.0 mm ( 0.59 inch) or less	25.0 mm ( 0.98 inch) or less
Bucket Cylinder	10.0 mm ( 0.39 inch) or less	15.0 mm ( 0.59 inch) or less	25.0 mm ( 0.98 inch) or less