I am still trying to figure this problem out... However, it really has me stumped. I tested the hydraulic pump and level controller valve on the 124TD per the service manual (by hooking hyrdaulic gauge to place where bleeder screw goes in level controller valve). The pressure was only getting up to 30 bar with the arm in "Fill" postion (it is supposed to get up to at least 133 bar). There were no leaks in the system, at least at that pressure, as it maintained 30 bar for days. That made me believe (WRONGLY) that the pressure relief valve in the level controller was shot, and I installed a new level controller valve (and accumulators, since I was under there anyway). It did not work. After all that, the pressure would still not exceed 30 bar, no matter what I did to the level controller arm.

As I see it, that leaves only 2 possible causes -- the hyrdaulic struts or the tandem pump. I think (maybe wrong) that the only way the struts could be causing the low pressure is if they were leaking. They are not leaking hydraulic fluid.

That leaves the pump. Is it possble for the tandem pump (which doubles as a stearing pump on this vehicle) to fail such that it would deliver low hydraulic pressure? The pump does not appear to have a pressure relief valve in it. It does have a shear pin, but I would think that if that failed, the pump would not pump at all.

Please, please provide thoughts on this. Both the struts and the pump are expensive to replace, and I would like to figure this out before throwing more money at it. Thanks much for any help.