H0010 Changing Overcentre Cartridge Blocks/Cap screws

There are three different types of blocks mounted to the hydraulic cylinders on a Sidelifter:

Both overcentre and check valve blocks have the potential to trap pressure in the cylinder even though the cylinder is not loaded and there is no pressure in the hydraulic lines from the blocks. It is essential to follow the following procedure. Failure to do so can cause serious injury due to the trapped pressure in the cylinder suddenly being released.

To demount all three types of blocks

1. Park the hydraulic cylinder in the rested position so there is no load on the cylinder. Note that the cylinder MUST not be fully extended.
2. Slowly back off the tube nut on the hydraulic pipe running between the "A" and "B" sides of the hydraulic cylinder. During this process the trapped pressure in the cylinder will be relieved and will flow out from the connection.
3. Once all pressure is relieved proceed with the removal of the valve block cap screws.
4. Loosen the cap screws holding the valve in place and remove valve.

To mount all three types of blocks

1. Connect the pipe between the block and the cylinder port. Do not tighten the tube nut.
2. Apply a covering of grease to the valve block o-ring cavity. Fit a new o-ring into the base of the valve block and fit block in place using new cap screws. Take special care that the o-ring remains in its correct position.
3. Fit new cap screws and tighten to 75Nm
4. Tighten the tube nuts.
5. Run all system and check for leaks.

To replace existing cap screws

When replacing existing cap screws it is strongly recommended that the o-ring be replaced at the same time. To do these please follow the procedure as outlined above.