Hello I have a 1995 kubota kx41 the engine cranks and runs fine the pump all 3 have 1200 psi at idle. But I have no movement on the boom nor tracks the push blade works. The swing some what works. The boom tries to move but don't. Same with the tracks they try but don't. I feel like I have no air in the line's. What can it be?
Why are you measuring at idle? What is psi at full throttle with system activated. Swing requires less psi than other functions.
was this problem sudden onset or is it a new to you machine? I looked at one once, only the blade moved and the thumb shot hydraulic fluid all over the seller's garage roof, all of the controls were frozen or jammed, it'd move if you leaned on it. It was too clapped out to be worth anything more than scrap value.
The psi at full throttle is around 3500 And I've owned this machine for a few months when I bought it the boom worked flawless the tracks worked flawless it would swing right but not left so I got my buddy that knows a little bit about hyd systems to check the pressure he said the pumps are all good doing as they should he told me just get the swing motor rebuilt and everything would be good to go that's what I did and now nothing works but it will swing I know there is no air in the system because sometimes the boom will work but it jerks and the rubber lines jump and stuff when I try to move something and the tracks will try to move and I hear a high pitch sound as well when I try to move the boom like a relief valve being stressed could it be like a main relief valve messed up? When I got the swing motor rebuilt the guy did say the relief valves was stuck shut
There you go. The main relief - check it....crossport relief - check it (if it has one). So, the swing works both ways now? No problem there? Did the swing motor guy mess with any hoses to the swivel? (that control blade and drive motors). If you have a schematic of hydro, it will tell you where the reliefs are...and since you can measure them, process of elimination. If you can do swing without an issue, I'd be inclined to look at relief for boom on valve block. I'm a newbie to hydro diagnostics, but I finally made up a hydro diagnostic kit, in which I can check just about everything using the diagnostic ports on manifold (it is also where the main relief is on mine - BC331). By using different controls one can figure out where the problem is...it does sound like one of the reliefs isn't doing it's job (your getting no return flow).