I am having hydraulic problems with a kobelco ed150. (its an equal to a 135sr, except an ed150 has a blade). The boom will not stay up, it just drifts down on its own. It will also not hold up the machine, it just drifts up (with down pressure on the boom). When switching control patterns the same problem occures (going from sae to iso pattern). The main control spool appears ok, (small swivel seal piece was found in with the spool). Removing the seal piece made no difference. When the boom is in the air, (drifting down), you can hear oil flowing through the main control valve. The machine also has had a recent pump failure. There are no error codes. Is there a holding valve or load checks somewheres to inspect?
They do not have holding valves .Check your relief cartridges .Their maybe some thing stuck in them and causing them not to build pressure or may just worn out.most likely .Your cylinder packings might be leaking inturneraly.You can do a cylinder leakage test by taking the rod end hose off .You will get some oil and stop flowing. But it should not keep flowing out .
I agree with tool king, the seal packings could be gone, or the pump failure could have put some debris in the cylinder and caused damage to the barrell, pistion or seals! i have seen this happen on wheeled loaders few times before!
GaryHoff the cylinder test is with boom raise a little bit off the ground and engine off don't gorget the releave hydrualic tank pressure.
Did cylinder leakage test, No bypass oil. Swapped boom reliefs with bucket reliefs. No change. I think its in the control valve, because i can hear oil flowing through it.
Gary Were the bucket reliefs the same pressure settings?They may have different setting.The contol valve might have blow seal or crack in it.
The bucket reliefs pressure are a little bit lower, but it shouldn't matter because it was just to check if oil was bypassing through the relief. The control valve doesn't have seals on the spools. I was thinking there may be a crack internally in the valve (that may be connecting the ports). But there is two problems with that theory, one, there should be lots of heat through the control valve. Two, the boom has stopped drifting down as fast, and once the problem stopped for about 10minutes. (when i made it stop i was working the machine hard, holding the boom over relief, cycling up and down)
What about the make up valves?
hi gary, if you like call me at work and provide the serial number too. YL0#-##### be sure to ask specifically for me. the machines do come standard with holding valves. however, they are not a " true holding valve ". a true holding valve or called cylinder lock valve is actually mounted directly to the hyd cylinder ports. your problem can be caused by many things, 1 or combinations thereof. if you make time so will i, when you call i'll need you in your cab in the machine. i will have you access the servicemans maintenance screens already built into the monitor display and we'll see if we can pin-point over the phone on where to concentrate your efforts. tks. Adam Fairchild, C.F.P.S. Parts & Service Manager Robert Green Equipment Sales Ltd. 41 Cardico Drive, P.O. Box 128 Gormley, Ontario Canada L0H 1G0 ph: (905) 888-9070 fax: (905) 888-9013 mobile: (416) 896-2442 home: (905) 697-9626 personal e-mail: [email protected] e-mail: [email protected] ROBERT GREEN EQUIPMENT SALES LTD. http://www.robertgreenequipment.com KOBELCO http://www.kobelcoamerica.com/Pages/homepage.aspx KOBELCO & MDI/YUTANI CUSTOMER ONLINE PARTS CATALOG (OPC) https://webparts.pvassociates.net/cnh/webparts/main.php HULTDINS http://www.hultdins.com/ INDEXATOR ROTOTILT http://www.indexatornorthamerica.com/
I would appreciate any help. The serial number is a yl05 (i dont know the rest right at this moment). I changed the lock valve (on the main control valve) as it appeared to be sticking somewhat. Now, the boom only creeps very slowly (still more creep than other units, but slow enough that it could go back to work) Also, it will hold itself up now. ??????? This makes it difficult to chase a ghost. The only other valve that i am leaning towards now, is one of the pilot backpressure valves, as i learned they were not changed after the pump failure. I was in the maintenance screens, and all pressures seemed to check out good. I have access to service manuals and schematics. Next time i am near this machine, i will be sure to call you for suggestions.