308D CR Mini Hydraulic 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, "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".

1. Perform the following steps in order to test the operating speed of the blade cylinder.

   1. Start the engine.

   2. Place the hydraulic activation control lever in the UNLOCKED position.

   3. Place the machine on level ground.

   4. Place the machine controls at the following settings: Engine speed dial "10" and AEC switch OFF.

   5. The bucket should be empty.
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   Illustration 1	g00727786
   (A) Extension test (B) Retraction test

   6. Position the upper surface of the boom parallel to the ground.

   7. Position the stick so that the stick is perpendicular to the ground.

   8. Fully extend the bucket cylinder.

   9. Fully retract the blade cylinder.

   10. With a stopwatch, measure the time that is required to fully extend the blade cylinder.

   11. Position the blade cylinder at full extension. With a stopwatch, measure the time that is required to fully retract the blade cylinder.

   12. Refer to the specifications in Table 1 for the operating speed of the blade cylinder.

Table 1

Cylinder Operating Speed (seconds)
Item		New	Rebuild	Service Limit
Blade	Extension	1.2 ± 0.5	1.6 (1)	1.8 (1)
	Retraction	1.2 ± 0.5	1.6 (1)	1.8 (1)

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