Relief Valve (Pilot) - Test and Adjust
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303.5E2 CR, 304E2 CR, 304.5E2 XTC, 305E2 CR and 305.5E2 CR Mini Hydraulic Excavators Hydraulic System
[UENR4294]
303.5E2 CR, 304E2 CR, 304.5E2 XTC, 305E2 CR and 305.5E2 CR Mini Hydraulic Excavators Hydraulic System
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303.5E2 CR, 304E2 CR, 304.5E2 XTC, 305E2 CR and 305.5E2 CR Mini Hydraulic Excavators Hydraulic System
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HYDRAULIC SYSTEM
VALVE GP-PILOT RELIEF
303.5E2 CR, 304E2 CR, 304.5E2 XTC, 305E2 CR and 305.5E2 CR Mini Hydraulic Excavators Hydraulic System
Relief Valve (Pilot) - Test and Adjust
303.5E2 CR, 304E2 CR, 304.5E2 XTC, 305E2 CR and 305.5E2 CR Mini Hydraulic Excavators Hydraulic System
Relief Valve (Pilot) - Test and Adjust
1.1. Specification
2.1. Introduction
3.1. Required Tools
4.1. Machine Preparation
5.1. Test Procedure
6.1. Adjustment Procedure
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Pilot Relief Valve Pressure Setting | ||
---|---|---|
Machine Settings | Engine Speed | |
Engine Speed Dial "High Idle" | ||
Item | Specification | Actual |
Pilot relief valve | |
The pilot relief valve limits the pressure in the pilot system. The pilot relief valve setting is adjustable.
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Required Tools | ||
---|---|---|
Part Number | Description | Qty |
198-4240 | Digital Pressure Indicator Gp | |
198-4234 | Digital Indicator | 1 |
198-4238 | Pressure Sensor Gp | 1 |
198-4236 | Adapter Cable As | 1 |
- Place the machine on level ground.
- Stop the engine.
- Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".
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Illustration 1 g06032321 Main control valve
(1) Pressure tap
(2) Jam nut
(3) Pressure reducing valve - Connect a
34450 kPa (5000 psi) pressure gauge to pressure tap (1).
- Start the engine.
- Place the machine controls at the following settings: engine speed dial "High Idle". Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.
- Place the hydraulic activation control lever in the UNLOCKED position.
- Increase the hydraulic oil temperature to
55° ± 5°C (131° ± 9°F) . - Stall any implement function and check the pilot pressure setting at pressure tap (1).
- The pilot pressure setting should be
4100 ± 200 kPa (594.7 ± 29.0 psi) . If the pilot pressure setting is not within the specification, adjust pressure reducing valve (3).
- Remove cap from pressure reducing valve (3) to expose the internal hex screw.
- In order to adjust pressure reducing valve (3), loosen jam nut (2).
- Turn the internal hex screw until the pressure gauge reading at pressure tap (1) is
4100 ± 200 kPa (595 ± 29.0 psi) .Note: Turn the internal hex screw clockwise to increase the pressure. Turn the internal hex screw counterclockwise to decrease the pressure.
Note: Always make final pressure adjustments on pressure increase.
- Tighten jam nut (2) to a torque of
8.1 ± 1.3 N·m (6.0 ± 1.0 lb ft) . - Repeat the"Test Procedure" to confirm the pressure setting.
- Replace the cap on pressure reducing valve (3).
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Illustration 2 | g06032327 |
Main control valve (2) Jam nut (3) Pressure reducing valve |
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