308D CR Mini Hydraulic Excavator Hydraulic System Caterpillar

Measuring the swing speed on a slope will determine if there is a need to check the swing motor and the anti-reaction valve. Measuring the swing drift on a slope will determine if there is a need to check the swing parking brake.

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, "Engine Performance - Test (Engine Speed)" for the engine speed that was used for this test. Refer to Testing and Adjusting, "Operational Checks" for 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, "Specifications".

Table 1

Required Tools
Description	Qty
Measuring Tape	1
Stopwatch	1

Illustration 1	g00298078

Swing Speed (Empty Bucket)

1. Empty the bucket.

2. Position the machine on a slope of 12 degrees. Refer to Illustration 1.

3. Position the implements at maximum reach and close the bucket. Position the bucket above the ground so that the bucket will not come in contact with any obstacles.

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Illustration 2	g00298079

4. Position the upper structure at position (A). The upper structure should be at a 90 degree angle to the lower structure. Refer to Illustration 2.

5. Measure the time that is required to swing the upper structure from position (A) to position (B) .

6. Position the upper structure at position (C). The upper structure should be at a 90 degree angle to the lower structure.

7. Measure the time that is required to swing the upper structure from position (C) to position (B).
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   Table 2

   Swing Time (seconds)
   Item	New	Rebuild	Service Limit
   Right Swing	4.6 or less	5.3 or less	6.0 or less
   Left Swing

Swing Drift (Loaded Bucket)

1. Load the bucket.

   Weight of bucket load

   308D ... 375 kg (827 lb)

2. Position the machine on a slope of 12 degrees. Refer to Illustration 1.

3. Position the implements at maximum reach and close the bucket. Position the bucket above the ground so that the bucket will not come in contact with any obstacles.

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Illustration 3	g00298079

4. Position the upper structure at position (A). The upper structure should be at a 90 degree angle to the lower structure. Refer to Illustration 3.

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Illustration 4	g00293972
(A) Upper frame (B) Undercarriage frame (C) Marking

5. To indicate the relationship of the two positions, put a mark (C) on the inner race and the outer race of the swing bearing. Refer to Illustration 4.

6. Stop the engine.

7. Leave the machine in this position for three minutes. Measure the swing drift on the circumference of the swing bearing.

8. Start the engine.

9. Position the upper structure at position (C). The upper structure should be at a 90 degree angle to the lower structure. Refer to Illustration 3.

10. Repeat Steps 5 through 7.
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    Table 3

    Swing Drift mm (inch)
    Item	New	Rebuild	Service Limit
    Right Swing	0	0	0
    Left Swing