303C CR and 303.5C CR Mini Hydraulic Excavators Hydraulic System Caterpillar

Measuring the swing speed on a slope will determine if there is a need to check the swing motor. 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
Tape Measure	1
Stopwatch	1

Illustration 1	g00816380
(A) 12 degrees

1. Complete the following steps in order to measure the swing speed on a slope.

   1. Start the engine.

   2. Place the engine speed dial in the HIGH IDLE position.

   3. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

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

   5. 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	g01154250

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

   7. Measure the time that is required to swing the upper structure from position (X) to position (Y) .

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

   9. Measure the time that is required to swing the upper structure from position (Z) to position (Y).
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      Table 2

      Swing Time
      Item	Specification
      	303C CR	303.5C CR
      Right Swing	2.8 sec or less	2.8 sec or less
      Left Swing

2. Complete the following steps in order to measure the swing drift on a slope.
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   Illustration 3	g01154250

   1. Load the bucket.

      Weight of bucket load ... 150 kg (331 lb)

   2. Position the upper structure at position (X). 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

   3. 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.

   4. Start the engine. Position the implements at maximum reach. Place the engine at the LOW IDLE position. Place the hydraulic activation lever in the UNLOCKED position.

   5. Leave the machine in this position for 3 minutes. Measure the swing drift on the circumference of the swing bearing.

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

   7. Repeat Steps 2.c through 2.e.

Table 3

Swing Drift
Item	Specification
	303C CR	303.5C CR
Maximum Drift	0 mm (0 inch)	0 mm (0 inch)