S3015, S3025 and S3035 Demolition and Scrap Shears Caterpillar

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At operating temperature, the hydraulic oil is hot and under pressure. Hot oils can cause burns. To prevent possible personal injury, release the pressure in the work tool hydraulic circuit (boom, stick, bucket, and swing), travel circuits, and the hydraulic oil tank at the filler cap before any hydraulic lines or components are disconnected or removed. Remove the filler cap only when the engine is stopped and the filler cap is cool enough to touch.

Required Tools

Adjustment Procedure

Illustration 1	g06329055

Illustration 2	g06209528
Speed Control Valve Group (MX) Measuring point for the Speed mode ON (MY) Measuring point for the Speed mode OFF (MAZ) Measuring point for the cylinder rod end (MAS) Measuring point for opening the cutter (MBS) Measuring point for the cylinder head end

Shift Pressure

1. Use Tooling (C). Connect a 34500 kPa (5000 psi) gauge on ports "MX" and "MY" of the speed valve.

2. Start the host machine. Allow the host machine to reach operating temperature.

3. Close the shear jaw while you watch the pressure gauge.

4. Gauge pressure at "MX" should rise. The pressure will fall to zero when the jaw is stalled. Record the maximum pressure that is observed at "MX". When the pressure at "MX" drops to zero, the pressure at "MY" will rise. Continue holding pressure until a maximum pressure is achieved at "MY". Record the maximum pressure at "MY".

5. If the pressure at "MX" drops to zero, proceed to step 6.

   1. Relieve system pressure.

   2. Adjust screw (B) counterclockwise in order to lower the shift pressure. Adjust the shift pressure so the pressure is between 70 percent and 85 percent of system pressure.

      Note: 1/8 turn is approximately 1068 kPa (155 psi).

   3. Go to Step 3.

6. If the maximum recorded shift pressure is below 70 percent of the recorded maximum system pressure, adjustment of the shift pressure is required.

   Note: Do not adjust while the jaw is moving.

   1. Relieve the system pressure.

   2. Turn screw (B) clockwise in order to raise the shift pressure between 70 percent and 85 percent of system pressure.

      Note: 1/8 turn is approximately 1068 kPa (155 psi).

   3. Go to Step 3.

7. The valve may not shift into force mode if the maximum recorded pressure is above 85 percent of the system pressure. The shift pressure should be adjusted in order to ensure proper valve operation.

   Note: Do not adjust while the jaw is moving.

   1. Relieve the system pressure.

   2. Turn screw (B) counterclockwise in order to lower the shift pressure between 70 percent and 85 percent of system pressure.

      Note: 1/8 turn is approximately 1068 kPa (155 psi).

   3. Go to Step 3.

Back Pressure

If the speed valve fails to transition into speed mode, check the back pressure on the open cycle. Back pressure should be a minimum of 10342 kPa (1500 psi) below the closing pressure with the speed valve in speed mode. This pressure differential is required to allow the spool to shift.

Increasing the open time for the extend or retract spools on the auxiliary valve creates a delay prior to the shear closing, which allows the back pressure to lower and the speed valve to function properly (depending on installation).

Note: If back pressure is too high, do not adjust spool stop (A). The spool stop should always be kept at maximum extension so that the spool stop does not inhibit spool travel (all the way counterclockwise).