been chasing an intermittent issue on said machine. When operating the left joystick which runs the main boom and grapple open/close sometimes it labors on the engine like I’m running a 3rd function and rarely when operating the outriggers. Checked all pressures which were spot on. Controls are pilot operated but it does have buttons to run the slasher. Found 2 broken wires going to the joystick but that wasn’t it. Tried unplugging the joystick since they weren’t running the slasher but it still shows up. Filters are clean. Anybody seen this before?
Did you check the canister filter in the lower frame? Sounds like an issue with the controller on the front pump. Worn linkage in the controller will cause this issue.
i haven't. do you mean the pilot filter? if so we changed that. i know barkos have the filter in the lower frame but i wasn't aware of any filter on the lower frame on the prentices. the machine has an unknown amount of high hours and the owner and i discussed that the pumps may be worn out but we found no amount of metal in any of the filters. are the pump controllers serviceable on these or would we just have to replace the whole pump?
There is a canister filter in the loader frame. It is not likely the issue but would be worth checking out IMO. The controller is servicalble. The oil tank would have to drained or vacuumed. Actual rotating group damage would not cause load on the engine. It seems from here that the pump is producing to much flow. There are no pressure adjustment s on the pump itself. The controller s function is much like the torque valves Barko used on the Parker pumps. I will send a pm later this evening.
Removing the displacement controller is simple, just a few tricks if you decide to go for it. You could swap the controllers to see if the problem moves to the jib.
So the pump has 2 controllers or I would be swapping them from another of the pumps? It sounds like I’ll be pulling it apart to inspect it so what kind of tricks do I need to know? TIA
There are two pumps back to back. Each controls half the valve stack. The controllers are identical. There is an arm on the controller that must be lined up with a pin on the servo piston , it will be easy to see what has to happen as soon as you remove the controller. The trick is on reinstallation when you think you have the arm lined lightly bolt the controller up, then back it off the pump just enough to get a thin peice of metal(slim Jim) and to move the arm both ways if it wont move you are good. Movement, arm not lined up.
You can remove the controllers with the pumps in place. I will get some pictures in the AM.
This a controller removed from a pump. The notch on the end of the arm is what must be over the pin on the servo piston.
Thanks for the picture. That clears things up pretty well. I’m not sure when I’m headed back. This machine feeds a chipper and can have 3-6 trucks hauling off of it so sometimes it’s hard to get my hands on it for more than an hour at a time.