i just went through a 4cx others had been working on for a similar problem. on this machine there is an electric solenoid on the right side of the backhoe valve body. it is operated by the switch on the right side panel. if you pull the two prong plug on the solenoid you can check it with a test light to ground for power and again if you power the test light check the ground in the plug. if ground good and power good solenoid should warm up. you may need to have backhoe running to check for power, if no power check fuses, if fuses good switch and plugs would be next. if solenoid is powered, given you don't have a bad electric valve, check lock adjustments adjustments. if bolts to loose will bind when starts to move. you are dealing with a lot of weight here so the adjustment is just enough to let it slide it will not feel loose, snug with short handled wrench. i figured you would have already cleaned off alc the dirt and old grease etc..
MARTIN, December 2013
