The machine is a D4Hseries2 with 6028 hrs. Does anyone know what the hydraulic pressure should be at the test port on the blade control valve? At an idle, it makes 200 psi. When I fully extend each blade function, I get three different pressure readings. Blade lift max pressure :1200 psi. Blade tilt max pressure :1600 psi. Blade angle max pressure :2700 psi. Additionally, It recently developed a pulse type of vibration that can be felt by hand in the hydraulic oil supply line to the pump. Any insight is appreciated.
Hello, it sounds like to me you have some bad seals on your ball resolver valves for the blade and tilt circuit. each circuit has its on set of primary and secondary ball resolver valves. they have orings on them and it is very common for them to get blown and when they do you loose pressure and power on that particular circuit. if you would like a picture and location of them put you serial # down and i will send you a picture or two.
Thanks for the good info, I think I'll replace the resolvers in both valves while the oil is drained from the system. The pump has a broken piston, so a replacement is on order. I'll keep you posted.
kbeen has a good idea there. the o-rings are teflon and not a typical o-ring so make sure you get them at the dealer or they won't last. i would be leaning towards pump. i think that has a piston/swash plate style pump. 1 of the pistons is probally out and the vibration (ecspecially if in main pressure line) is constant it is just like an engine missing. if vibration is in return line only could be a suction leak or most probally the lift or tilt circuit relief valve or one of there check valves hanging slightly open. if the lines from control valve are over heating i would lean towards that. any way...just a couple other things to keep in mind.
I took the pump off, and one of the pistons had a piece broke off. That explains the vibration, and I spoke with a local hydraulic mechanic and his thought was the same as kbeen's for the pressure loss. Thanks for the great feedback!