VT-30, VT-40, VT-50 and VT-60 Multi-Processors Hydraulic Cylinder Cycle Time - Check Caterpillar

The host machine must be operated at high idle during this check.

1. Move the host machine with the work tool to a smooth level location.

2. Turn off the engine on the host machine and activate the parking brake.

3. Conduct a good visual inspection of all hoses, fittings, and components. If any leaks or any damage is observed, replace the faulty components before you attempt this check.

4. Start the host machine and run the machine at high idle. Operate the implements until the hydraulic oil reaches normal operating temperature.

5. Fully open the jaws of the work tool.

6. Close the jaws of the work tool and record the cycle time.

7. Open the jaws of the work tool and record the cycle time.

   The cycle times for each model are listed in Table 1.

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   Table 1

   Sales Model	Closing Time	Opening Time
   VT-30	1.9 seconds	3.2 seconds
   VT-40	2.0 seconds	4.2 seconds
   VT-50	2.6 seconds	3.8 seconds
   VT-60	3.1 seconds	4.3 seconds

8. If the cycle times are within the specifications, the jaw circuit is operating properly. If the cycle times are not within the specifications, check the oil flow and the oil pressure from the host machine. Refer to the Service Manual, "Host Machine Pressure and Flow - Test".

9. If an adjustment was made to the host machine, repeat the test. If an adjustment was not made or if the cycle times are not within the specification, check the speed control valve. Refer to Service Manual, "Speed Control Valve (Hydraulic Cylinder) - Test and Adjust".

10. If an adjustment was made to the speed control valve, repeat the test. If an adjustment was not made or if the cycle times are not within the specification, the seals within the cylinder may be worn. Check the cylinder seals for leakage. Refer to Service Manual, "Hydraulic Cylinder Leakage - Test".