Relief valve 333/C8656 JCB 3CX/4CX 252 bar, aftermarket

For the JCB 3CX and 4CX backhoe loaders: relief valve 333/C8656, 252 bar, an aftermarket part.

The cartridge valve screws into its cavity in the valve body, and its O-rings and back-up rings separate the passages in the cavity. The spring inside sets the pressure; spring fatigue or a worn seat lowers it. Particles in dirty oil can hold the valve open. The setting can only be confirmed by measuring with a gauge. The aftermarket valve matches the original in cavity size, thread and set pressure. A leaking relief valve usually shows as hot oil and loss of force in the related function, and a new valve may leak too if the cavity and O-rings are dirty. When fault-finding, a suspect valve can be swapped with a valve of the same setting from another cavity to see whether the fault moves with it. The valve is supplied new. The valve comes with its O-rings fitted.

Specifications

Compatibility

The catalogue also has the genuine version of this part. Other parts are in Hydraulic valves.

Fitting

Remove every piece of the old O-rings from the cavity, as a leftover fragment will make the new valve leak.