302.7D CR Mini Hydraulic Excavator Caterpillar

Cylinder Drift - Check

Usage:

Specification

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Table 1
"Cylinder Drift - Check (Empty Bucket)"⁽¹⁾
Date:		Machine Serial Number:
Item	Cylinder Position	New	Actual
Boom Cylinder	Extended	2.5 mm (0.1 inch) or less
Stick Cylinder	Retracted	5 mm (0.20 inch) or less
Bucket Cylinder	Extended	10 mm (0.39 inch) or less
Boom Swing Cylinder	Extended	10 mm (0.39 inch) or less
Boom Swing Cylinder	Retracted	10 mm (0.39 inch) or less
Blade	Retracted	10 mm (0.39 inch) or less

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⁽¹⁾	Drift specification after 5 minutes

Introduction

The performance level of the cylinder, the cylinder seals, and the overload relief valves for the implements can be determined with the following procedure.

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".

Required Tools

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Table 2
Required Tools
Description	Qty
Measuring Tape	1
Stopwatch	1

Test Procedure for Boom, Stick, and Bucket Cylinders

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

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Illustration 1	g02887661

Fully extend the bucket cylinder.
Fully retract the stick cylinder.
Extend the stick cylinder rod 70 mm (2.8 inch) from the fully retracted position.
Raise the boom until the stick to bucket pin is the same height as the boom foot pin. Refer to Illustration 1.
Measure each cylinder length from cylinder pin to cylinder pin.
Stop the engine.

Leave the machine in this position for 5 minutes. Measure each cylinder length from cylinder pin to cylinder pin for drift.

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Table 3
Cylinder Drift
Item	New	Actual
Boom Cylinder Retracted	2.5 mm (0.1 inch) or less
Stick Cylinder Retracted	5 mm (0.20 inch) or less
Bucket Cylinder Extended	10 mm (0.39 inch) or less

Test Procedure for Blade Cylinder

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Illustration 2	g02887662

Start the engine.
Position the machine on level ground.
Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).
Position the stick so that the stick is perpendicular to the ground. Lower the stick to the ground. Refer to Illustration 2.
Fully retract the blade cylinder. Extend the blade cylinder 10 mm (0.4 inch) from the fully retracted state.
Measure the length of the blade cylinder from cylinder pin to cylinder pin.
Stop the engine.
Leave the machine in this position for 5 minutes. Measure the length of the blade cylinder from cylinder pin to cylinder pin for drift.

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Table 4
Cylinder Drift
Item	Specification	Actual
Blade Cylinder	10 mm (0.39 inch) or less

Test Procedure for Boom Swing Cylinder

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Illustration 3	g02887664

Start the engine.
Place the engine speed dial in the HIGH IDLE position.
Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).
Position the machine on a slope of 12 degrees. Refer to Illustration 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 4 g02878336
Position the upper structure and boom at position (X). The upper structure and boom should be at a 90 degree angle to the lower structure. Refer to Illustration 4.
Measure the length of the boom swing cylinder.
Stop the engine.
Leave the machine in this position for 5 minutes. Measure the length of the boom swing cylinder.
Repeat Steps 6 through 9 with the machine at position (Y).
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Table 5
Cylinder Drift

Item Specification Actual

Boom Swing Cylinder (Extended) 10 mm (0.39 inch) or less

Boom Swing Cylinder (Retracted) 10 mm (0.39 inch) or less