Technical reference page: 89

Pilot operated check valves - electro-hydraulic spools

The electro-hydraulic spool valves fitted on the Stealth sometimes suffer from leakage pasts the spools which allows the hydraulic rams to creep. Pilot operated check valves are fitted to two of the spools as standard. They can also be retro-fitted to the other two if required.

To fit a check valve proceed as follows:

Remove the chemical inductor (if fitted), Remove the outer guard and clean the area around the spool valve thoroughly. Take care not to pressure wash the electrical connectors.

Undo the centre screws securing the two electrical connectors onto the electro spools and remove the connectors.

Undo the four allen-headed bolts securing the centre of the spool to the valve block.

Pull the electro-valve away from the block and fit the pilot check valve in between the electro-spool and the block. The check valve face with the O rings should face towards the manifold block. Take care to ensure that the O rings on the back of the spool and on the back of check valve are not dislodged.
NB Take great care to ensure that no dirt enters any of the ports and ensure that the mating surfaces are kept clean.

Secure the spool/check valve onto the block with the longer bolts provided.

Replace the two electrical connectors.

Test the valve to ensure it is working correctly and check for leaks before re-fitting cover etc.