J C B 3cx sticking levers

[hubert]

Working at a friends jcb 3cx today. The first job we tackled was freeing up the levers on the front shovel. They were really stiff. We put some wd40 around the linkage and that freed up the lever a bit. We also freed up the pistons in the control box which made a big difference. We thought we had sorted the problem but when we moved onto another job & then came back later in afternoon to drive the machine the levers had
tightened up again. Once we got the levers moving they were not too stiff but not as free as they should be.The spring loaded return to the central neutral position is not happening. Do we need to take off all the hydraulic hoses and remove the control box and dismantle to sort out our problem of the sticking levers? What would be the cause of this. Thank you in advance for any information to sort this problem.

[essexpete]

Is there an easy way of disconnecting the linkage to the spool end to see where the problem lays?

[hubert]

Disconnected the linkage the linkage and the stiffness seemed to be in the control box. The machine has not been used for a while. Would the pistons in the control box stiffen up with sitting around.

[essexpete]

The spools in the chest will be metal machined to a fine tolerance with metal to metal sealing lubricated by a very thin coating of oil. If the tolerance is increased then the spool will leak internally or worse externally. If the machine has stood and moisture has got in, either by contaminated hydraulic oil or from the outside there could be corrosion damage. It might also be there is some degraded oil causing the stiffness.