Is it possible for one to bypass the 4 system, and operate the machine on Pilot Pressure? Machine is early 90's....My father thinks its a 1993. Serial Number is 8818. His machine is always out on jobs 50-75 miles from me. I do not have any pictures of the machine, hours or service history available at the moment. It was purchased from Casterline Diesel in Sweet Valley Pa by us 3 years ago. He's had issues with the offsetting boom hydraulics drifting and at times getting locked out to one side. The valve for it was replaced with a hand valve, the part from Komatsu was more than he was able and willing to dump into the machine. Still drifting and locking out from time to time. Anyone ever removed the 4system and controlling the machine with just Pilot Pressure? Anyone have an idea how to, plans of attack, time and cost estimates? Appreciate the wisdom
That machine operates on pilot pressure. Are you talking about eliminating the pattern changer? Easy enough to do, though I don't know why you would want to? I'm sure the boom offset does not go through that, only the four joystick functions (bucket, arm, boom, swing). Are there issues other than the boom offset problem? If what was changed for the boom offset was just a replacement for the pedal controller it's probably just a pilot control which I doubt was the problem to start with,since the problem still occurs it will probably be in the main valve, lock valve if it has one, piston packing, etc.
The valve assembly under the foot pedal control for the offsetting boom is what was worn out and was too expensive for my father to purchase at the time. His machines are not daily runners, so he isn't able to justify a $700 dollar part for a machine. they re-routed some hoses and installed a hand valve on the wall of the rops. He and a mechanic have looked over the machine thoroughly. They have had this machine in pieces before, but I personally have not inspected simple things like piston packing or tore into it myself to inspect anything else. I know they have spent extensive time looking into this drifting issue. I haven't spoken to him in a couple days so my memory isn't very crisp, but I recall him saying something along the lines of "try to see if anyone knows if the 4system is a brain for the hydraulics/controls or not". Not sure if this has helped you understand the scenario any better.
If I'm remembering this correctly the 4 link system is mainly to prevent the machine from having enough range to hit the cab or other parts of the machine when the Z boom is articulated. There was also some kind of depth monitoring system that utilized the 4 system potentiometers, never figure out how that part of it worked but it was an interesting concept given when these machines were developed. Not sure how to bypass the system completely but if there is ever any plan to resell it I would really stay away from totally dismantling it. I had a PC-75uu-2 and under the seat, accessible from between the operators knees , was a spring loaded toggle switch that would over ride the system. At one point I had a wire in place to hold the switch open so I could finish a job..... Not sure what the long term affects would be of running it this way, or possibly if one studied that part of the system you could figure out how to dismantle it electrically if that's what you really want to do.