Usage:
This article is a reprint of an earlier article which was printed in the July 6, 1981, Service Magazine.
A new 6V3176 Cylinder Relief Valve Assembly is available for use on cylinders without a relief valve. It can be added to the rod end of any center hole two-way (double acting) cylinder, which is rated for 69,000 kPa (10,000 psi) operation. The 6V3176 Valve gives extra protection to the service tool. It prevents an increase in pressure caused by a restriction (blockage) of the return oil to the pump. The relief valve setting is 72,450 kPa (10,500 psi). When there is too much pressure, the operator can see the oil drops released through the relief valve.
Illustration 1. 6V3176 Relief Valve Assembly.
Make an inspection of your center hole cylinders to see if they have a relief valve. Two possible locations of the valve are shown. Illustration 2 is an example of an external location. Illustration 3 is an example of an internal location. Be sure to check only the correct hole shown in the illustration.
All 6V113, 6V14, 5P5201 and 5P9696 Hydraulic Cylinders already have internal relief valves. Some 5P2997 and 5P2998 Hydraulic Pullers have external relief valves already. Relief valves were not installed on 1S4233, 5H9817 and 3P1573 Hydraulic Cylinders at the factory.
Illustration 2. Example of external location of relief valve.
Illustration 3. Example of internal location of relief valve.