Saturday 21 July 2012

Disassembling and reassembling the electric hydraulic spool valve block


Preliminary operations
Disconnect the control cables (7) from the mechanical component(s) (if fitted).
Mark the position of the hydraulics hoses connected to the couplers. Disconnect them from the spool valve block.


Disconnect:
- the high pressure pipe (30);
- the lift ram supply pipes (16);
- the LS hose (9).
Mark then disconnect:
- the lift control valve solenoid valve harness (R10 Down - R11 Up).
- the V2, V3, V4 connectors (depending on option) from the electrohydraulic spool valve pilot valve(s);
- the R23 connector from the end plate (6) ON/OFF solenoid valve.

Removal
Remove the screws (3) and flanges (2) from the manifold (21).


Sling the spool valve block. Separate it from the support (1). Place it in a clean work area. If necessary, remove support (1).


Discard the O'ring (3).

Install
If it was necessary to remove the support (1), replace the return pipe (3) O�rings (2). Tighten the screws (4).
Clean the manifold (21) mating face, along with that of the support (1).


If the studs (2) need replacing, lightly smear the short thread of the new studs with Loctite 270 or equivalent. Install and tighten the studs. Clean off any excess Loctite. Replace the O�ring (3).
Install the distribution block on the support (1). Tighten:
- the screws (3) to a torque of 50 - 70 Nm;
- the nuts (2) to a torque of 90 - 120 Nm.


Reconnect the following according to the marks made during removal:
- the lift control valve solenoid valve harness (R10 - R11);
- the V2, V3, V4 connectors (depending on option)
from the electrohydraulic spool valve pilot valve(s);
- the R23 connector from the end plate (6) ON/OFF solenoid valve.
Reconnect:
- the LS hose (9);
- the lift ram supply pipes (16);
- the high pressure pipe (30).
Connect the coupler hoses to the spool valve block.
If fitted, reconnect and adjust the control cables of each mechanical spool valve. Perform the hydraulic tests if one or more spool valve block components needed replacing.

Disassembly
Carefully clean the spool valve block prior to disassembling. Remove any traces of dried mud or earth that could contaminate any spool valve components that could be recovered.
Place the spool valve block in a vertical position.


Loosen the nuts (1). Remove the end plate(s) (right and/or left) from the spool valve block. Separately remove the concerned spool valve components, making sure not to lose:
- the O�rings between each component;
- the non-return valve (1) and its spring on the manifold (21).


If necessary, loosen the six studs screwed on either side of the manifold (21). These studs may be of variable length depending on the number of components fitted onto the spool valve block.

Reassembly
Clean the mating faces:
- of the manifold (21), without removing the adhesive shims (pellets P,);
- the spool valve component(s) (auxiliary and lift control)


If the studs on the manifold (21) need replacing, lightly smear the short thread of the new studs with Loctite 242 or equivalent. Install and tighten the studs. Clean off any excess Loctite.


Check the presence:
- of the seals (3) (4) (5) (7) in each spool valve (1) spot-faced port;
- of the seals (3) to (7) in each manifold (21) spot-faced port;
- of the non-return valve (1) and its spring on the manifold (21);


- of the adhesive shims (pellets P,).
Reassemble the spool valve block by assembling the spool valve component(s) on the manifold (21).
The lift control valve is integral to the auxiliary spool valve block components. It is located between the manifold (21) and either the right-hand end plate or the 4th spool valve component (if fitted).
Reinstall the end plate(s) (right and/or left) on the spool valve block.


Install and alternately tighten the nuts (3) to a torque of 30 - 33 Nm. This torque must be respected in order to avoid any risk of spool valve component warping and subsequent spool jamming.

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