(Any help would be greatly appreciated) I recently purchased a 2002 link belt 3400 Quantum. Machine had a bad oil leak and fuel leak but operated decent and all functions worked. Replaced turbo and o-rings on top of injection pump and fixed both of those problems. Now the new problem has begun. The machine will operate great then all of the sudden the arm struggles to lift up at all if it does lift then it is very slow. Although if you move arm out while lifting up it goes normal. It’s as if it’s bypassing or something but it goes in and out. One minute it’s working then it all of the sudden stops. The only way it will work is if another function is engaged. All other functions appear to be working great. I’ve changed Both fuel filters, large in tank hydraulic filter, small hydraulic filter next to pump, and hydraulic tank relief air filter on top. Clueless on where to go from here. Please help!!
does the machine have a functional digital display monitor by any chance?
Did you figure it out? Almost sounds like the pump isnt stroking
Follow the boom hydraulic pipe to find the distribution valve safety valve, remove it and use a screwdriver to press the safety valve pin to see if it can be pressed down.