CB-634D Vibratory Compactor Vibratory System Caterpillar

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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the vibratory system.

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

Note: The pressure of the charge relief valve must be checked before you adjust the pressure for the main relief valve.

Note: The hydraulic oil temperature should be at least 38°C (100°F).

Illustration 1	g01129370

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Location Of Components In The Vibratory Pump (1) Vibratory pump (2) Pressure override (3) Valve cap (4) Pressure tap (5) Pressure tap (6) Valve cap

1. Before you conduct the testing and adjusting on the vibratory valve, the following steps must be followed:
   • Apply the parking brake.

   • Place the speed/direction control lever in Neutral.

   • Place the vibratory switch in the automatic position.

   • Place tires under both drums.

2. Connect tool (B) to pressure taps (4) and (5) .

3. Disconnect the line from the pressure override (2) to the vibratory pump (1). Plug and cap the fitting immediately.

4. Start the engine. Run the engine at high idle.

5. Place the vibratory switch in the dual drum vibration mode with the eccentric weights at high amplitude.

6. Move the propel control lever to the forward direction. Record the maximum pressure on the gauge at the pressure tap (5). This reading must be taken when the vibratory system is started or stopped. The high pressure relief valve setting is 36000 ± 1700 kPa (5220 ± 250 psi).

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Illustration 4	g01129363
Relief Valve Cartridge (7) Spindle (8) Collar (9) Lock screw

7. If the main relief valve pressure is not correct, adjust the cartridge according to the following procedure:
   • Stop the engine.

   • Remove the forward valve cap.

   • Remove the high pressure relief valve cartridge. Install the cap of high pressure relief valve (6). This will ensure that the oil does not leak while adjustments are made to the cartridge and the spring.

   • Hold the high pressure relief valve cartridge in a bench vise. Secure the high pressure relief valve cartridge by clamping on collar (8) .

   • Loosen lock screw (9) with a 3 mm Allen wrench.

   • Use a 5 mm wrench and adjust the pressure by turning spindle (7). Turn the spindle clockwise in order to increase the pressure. Turn the spindle counterclockwise in order to decrease the pressure. One full rotation of spindle (7) equals 4400 kPa (638 psi).

   • Tighten lock screw (9) .

   • Remove the high pressure relief valve from the vise.

   • Reinstall the high pressure relief valve cartridge. Install the cap of high pressure relief valve (6) and torque to specifications.

8. Repeat Step 6.

9. Stop the engine.

10. Remove the plug and the cap. Reconnect the line for the pressure override (2) .

Follow the same procedure to adjust the high pressure relief valve (3). Move the propel control lever to the reverse direction. The reverse high pressure relief valve cartridge is located under valve cap (3). The pressure is checked at pressure tap (4).