Valve block 25/407900 JCB, genuine

Valve block 25/407900 is a genuine JCB part for the JCB machines.

A valve block is a control valve group that combines the spools of several hydraulic functions with relief and check valves in one body. Each section serves one function, and the spools are moved by levers or by pilot pressure. A worn block causes internal leakage, slower functions, arms creeping under load and hot oil. When replacing it, compare the section count, spool types, control type and ports with the old block. The block is heavy and costly, so the spools, relief valves and seals are checked one by one before deciding to replace it, as the fault is often confined to one section. Pressure settings are made at the factory and confirmed with a gauge after fitting. Mark the control linkages and pilot lines and reconnect them in their original places. The block is supplied new with its ports capped and spool ends protected. If the system has run on dirty oil, clean the tank and renew the filters along with the block change. The block is heavy. The block body is a casting.

Specifications

Compatibility

Other parts are in Hydraulic system.

Fitting

Mark the hoses and relieve pressure before removing the block. Connect the new block with new O-rings and adjust the controls; on first start, slowly run every function through its full stroke to purge air and measure the pressures.