Hi I have a hitachi mini ex-35. I just rebuild the Kubota motor. The hydraulics were all strong and fast prior to the engine work. I reinstalled the pump when installing the engine, refilled hydraulic oil and bleed the air out of the pump with the Allen screw and hydraulic lines on the pump. I can’t get pump pressure to run the cylinders at a normal rate. When at idle they run faster then with higher RPM’s, there is no whining. There was whining initially then I shut it down and bled the system. I’ve attempted multiple bleeds but I suspect an air issue as the speed decreases when RPM’s raise. Any suggestions? All functions are slow, blade, tracks and stick
It has a Nachi piston pump.
Nachi Pvd 0b 22P?
Nachi PVD-2B
Whining is not a good sign, is there a chance that the supply hose was contaminated..there could be a valve plate damage
when bleeding air,doid you touch this screw?
I read the op manual for the newer model last night, it said the bleed procedure was operate it for 15 minutes at idle, then slowly increase speed for another 15 minutes. Works great now. I’ve never heard of such procedure but 30 minutes later it works even in a cold Wisconsin 10 degree night. Always learning!
[COLOR=var(--YLNNHc)] great I personally do not bleed the pump when I install it, in fact there is no need for bleeding because when I connect the pump to the engine I immediately connect the supply hose from the reservoir and while I tightening that hose the oil just flows to the outlets from the hose leading to the main valve and that is the best natural bleed because the reservoir is certainly above the level of the hydraulic pump itself...there is always a slight doubt that there is an air pocket when all the hoses are first connected and then bleeded.. 10 min of idle is a must.. [/COLOR]