I've bought a Samsung Se50-3 with 2300 hrs that is having hydraulic issues for a reasonable price. At full throttle, all the boom functions move very slowly, the blade will move up and down very slowly occasionally, and the cab swing doesn't work at all. The boom swing and tracks work perfectly normal. I noticed that both the functions that work, their controls are located on the floor and go directly to the main control manifold. I was told the pump needs to be replaced but I don't agree. I think it might be a hydraulic filter or air/water in the lines. I noticed there was a hydraulic line from the pump to an inline filter, then to a manifold with three solenoids, maybe one of those is bad. I'm still waiting for the operations and maintenance manual I ordered to arrive, so I don't know what anything does yet. I was wondering if anyone else had a machine like this and knew more about it. The SE50-3 is pretty much the same as the Volvo EC55B. This is my first piece of equipment at the ripe age of 20 so I've got a learning curve on the mechanical side of things. Any preliminary ideas would be welcomed.
pilot pressure issue perhaps, could be the pilot pressure relief valve that need's adjusting or it might have a separate pilot pump and that is bad.
Sound like your pumps are not swashing all way as thet call it .Make sure your suction screen in the tank leading to the pump inlet is clear of debris. I have founds ome weird things in machine tanks. Drain tank to see suction screen.Do not just pull out with oil in tank .Debris can fall onto suction line .Than when you start up machine it will be sucked into pump .Make sure you pilot pressure is good.Check you main pump pressures.Make sure you have good filters in the machne that are clear The swing and track dont demand that much swash.Low flow will make them move .At full throttle what is the rpm of the engine .If engine is not running were it should be you will not full swash of the pumps.
Got my manual today, from that was able to deduce what i think it is. the safety lever next to the seat halts the same three functions that i don't have working on my machine. The safety lever shuts off the pilot pressure using a set of solenoid valves using a switch to trip them. I think there is a wiring issue or the little switch the lever trips is broken. Going to do some more experiments tomorrow.
Just an update. I've ruled out electrical issues with the safety lock. I bled the hydraulic system of air according to instructions in the manual. I changed the pilot filter, cleaned the suction screen, and checked the hydraulic return filter. I've noticed a kind of buzzing sound coming from one of the hoses attached to the swing motor, the more throttle the more noise, and am going to crack that next chance I get. Maybe it is a piece of a valve loose in the hose clogging up the pilot pressure line. Could one bad valve screw up the pressure for the whole system? I have an actual service manual coming soon, hopefully that will give me some more insight into how the whole system works.
measure the pilot pressure.
Got a gauge, it reads up to 10000 PSI, not the best to measure pilot pressure. Anyway, the needle didn't even jump at full throttle. I was able to the move the attachments very slowly, but the needle didn't move. Tried adjusting the pilot pressure but didn't do anything. Going to remove the gear pump for the pilot pressure and possibly replace the relief valve for the pilot pressure. Interestingly, the valve is right on the pump, as well as the test port. Going to get another gauge, but will probably take a week to get here. Any ideas? Haven't checked out the buzzing I've heard near the swivel joint. All the troubleshooting flow charts in the service manual point toward the pilot pump or pilot relief valve.
drained fluid removed pilot pump, didn't look like anything was wrong with it, all the teeth looked good, spun nice and tight. i was looking at my hydraulic schematic and it seems there are filters before the remote control valves. i don't know where they are, anybody have an idea where they could be in relation to the joysticks?
If you plug the pressure outlet from the pilot filter/relief assembly, do you get the correct pressure then?
I see what you mean, I can't do it now though cause I drained the fluid and am going to take the pump out to have it bench tested. Basically I'm gambling it's the pump. Looking at my schematic, there is a direct line from the pilot pump to the swing brake release valve, which I have no function out of. This combined with no pressure on the test gauge leads me to the conclusion the issue is in the internals of the pump. My thought now is that the relief valve is bad and letting all the pressure out of the pilot system, either through the seat or the valve is failed completely. You have to take the whole pump apart to get to it though so I'm just going to pay to have it bench tested and repaired if necessary. Taking it out is a hitch, I don't even have a big enough wrench to pull it apart. Yet.
I know this is a dated thread, but I have a EC55B that is having similar issues. I was wondering if you ever got your machine working right(and remember what the issue was)? Thank you for your time
Good day Please see attched I hope it helps if you have questions please drop me a line. Kind regards Uffex
Additional standard information
Can you please send me the copy of the manual as i have the same issue. My samsung machine 40 W doesn't swing at all . The swing motor was changed. I bought a used machine it dint have any connection for hydraulic oil pipe to the swing motor brakes function . ( OLD MOTOR SWING MOTOR PIPE WAS DISCONNECTED AND HAS NO ELECTRICAL RELAYS/ CONNECTION) Please let me know do all excavators have swing motor brake function. Its an old mechanical control machine.