312F and 313F Excavator Machine Systems Relief Valve (Blade) - Test and Adjust - If Equipped Caterpillar

Specification

Required Tools

Illustration 1	g02571852
Tooling (A) 198-4240 Digital Pressure Indicator Gp

Machine Preparation

Illustration 2	g03531319

1. Position the machine on level ground in the service position. Refer to Illustration 2.

2. Stop the engine.

3. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "System Pressure - Release".
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   Illustration 3	g03722121
   Blade control valve (1) Pressure tap (blade pump) (2) Blade main relief valve (3) Blade line relief valve

4. Attach 41,368 kPa (6,000 psi) pressure sensors to pressure tap (1).

Test Procedure

Note: A temporary setting of the main relief valve is required before any line relief valves can be adjusted. Refer to Table 4 for temporary main relief setting for the function being tested.

Note: Pressure values in Table 5 are approximate values. Use a pressure sensor for adjustment.

Note: A continuous relief of the valve for more than 10 seconds is not allowed.

Blade Main Relief Valve

1. Position the machine on level ground.

2. Stop the engine.

3. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".

4. Connect a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (1).

5. Start the engine.

6. Place the machine controls at the following settings: engine speed dial "10" and AEC switch OFF. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.

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

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

9. Slowly move the blade control lever to the full RAISE position and check the pressure reading at pressure tap (1). Refer to Table 1 for the specification.

10. Return the blade control lever to the NEUTRAL position.

11. If the setting of the blade main relief valve is not within the specification, adjust the relief valve. Refer to adjustment procedure "Blade Main Relief Valve".

Temporary Setting of the Main Relief Valve

Note: A temporary setting of the main relief valve is required before any line relief valves can be adjusted.

1. Connect a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (1).

2. Perform the following steps to make a temporary adjustment to the blade main relief valve.

   1. Move the blade control lever until the blade is at the full RAISE position (full retraction of the blade cylinder). Hold the blade control lever in this position.

   2. Check the pressure setting of the blade main relief valve at pressure tap (1).

   3. Return the blade control lever to the NEUTRAL position.
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      Illustration 4	g03722285
      Blade control valve (main relief) (2) Blade main relief valve (4) Locknut (5) Adjustment screw

   4. Loosen locknut (4) on blade main relief valve (2). Turn adjustment screw (5) until the pressure reading at pressure tap (1) is 27500 kPa (4000 psi).

      Note: Turning adjustment screw (5) clockwise increases the pressure. Turning adjustment screw (5) counterclockwise decreases the pressure.

      Note: Always make final pressure adjustment on pressure rise.

   5. Tighten locknut (4).

3. Reset main relief valve pressure setting to the normal operating condition after the completion of the line relief test and adjust.

Blade Line Relief Valve

Note: A temporary setting of the blade main relief valve is required before the blade line relief valve is adjusted. Refer to "Temporary Setting of the Main Relief Valve".

Note: Refer to Testing and Adjusting, "Specifications" for the pressure setting of the blade relief valves.

1. Connect a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (1).

2. To check the pressure setting of the blade line relief valve, move the blade control lever to the full LOWER position (full extension of the blade cylinder). Hold the blade control lever in this position.

3. Check the line relief valve pressure setting of the blade cylinder at pressure tap (1).

4. Return the blade control lever to the NEUTRAL position.

5. If the setting of the blade line relief valve is not within the specification, adjust the relief valve. Refer to adjustment procedure "Blade Line Relief Valve".

6. Return the pressure setting of the blade main relief valve to specification after adjusting the blade line relief valve. Refer to Table 2 for the pressure setting of the blade main relief valve.

Adjustment Procedure

Blade Main Relief Valve

1. If the setting of the blade main relief valve is not within the specification, adjust the relief valve. Refer to Table 1 for the specification.
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   Illustration 5	g03722285
   Blade control valve (main relief) (2) Blade main relief valve (4) Locknut (5) Adjustment screw

2. To adjust blade main relief valve (2), loosen locknut (4) on the blade main relief valve (2). Turn adjustment screw (5) until the pressure reading at pressure tap (1) is within the specification . Refer to Table 1.

   Note: Turning adjustment screw (5) clockwise increases the pressure. Turning adjustment screw (5) counterclockwise decreases the pressure.

   Note: Always make final pressure adjustment on pressure rise.

3. Tighten locknut (4).

Blade Line Relief Valve

Note: A temporary setting of the blade main relief valve is required before the blade line relief valve is adjusted. Refer to "Temporary Setting of the Main Relief Valve".

1. If the setting of the blade line relief valve is not within the specification, adjust the relief valve. Refer to Table 2 for the specification.
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   Illustration 6	g03722288
   Blade control valve (line relief) (3) Blade line relief valve (6) Locknut (7) Adjustment screw

2. To adjust blade line relief valve, loosen locknut (6) on the blade line relief valve (3). Turn adjustment screw (7) until the pressure reading at pressure tap (1) is within the specification. Refer to Table 2.

   Note: Turning adjustment screw (7) clockwise increases the pressure. Turning adjustment screw (7) counterclockwise decreases the pressure.

   Note: Always make final pressure adjustment on pressure rise.

3. Tighten locknut (6).

4. Return the pressure setting of the blade main relief valve to specification after adjusting the blade line relief valve. Refer to Table 1 for the pressure setting of the blade main relief valve.