I'm Having a problem with my blade not going up or down when the machine gets hot. All functions work perfectly when cold but after 3 or 4 hours of hard work the blade stops responding. It makes a feeble attemt to go up(or down) and has no power. When these syptoms appear all other fuctions work normally. The blade is powered with it's own gear pump through a control valve then through the center joint to the ram. I've pulled the system relief valve on the control valve and it looks fine (it wasn't sqealing anyways) I also checked the control valve cable and it's fine. I've phoned service techs at various dealers and they all scratch their heads on this one The machine has 4000 hours.---This is my first post and any help would be appreciated.
Id say check the ram seals!
Well I don't know about that, if the seals are that bad it would be a case of not really working hot or cold. Or at the the very least would not be able to lift the machine even when cold. Remember as things get hot the seals expand, sure the hyd oil may get a bit thinner bit not to the extend that it will not even lift the blade up. Boomer, does the blade work well when the machine is cold, like lift the front of the ex up without problem, or even lift the whole machine in conjunction with the boom? I think your first step is to check the hyd pressures of that circuit both when hot and cold.
Do a bypass test on the cylinders. Also could be the centre joint (rotary manifold) seals bypassing. Both of these will give you good performance cold but diminishing performance as it gets hot. Having said that I would think the blade would drift when hot. Doing a pressure test cold then hot and finding reduced pressure will not pinpoint Pump, Relief, Centre Joint or Cylinders. Once you confirm those then you can go onto the pump and relief.
Yes, Hendrik, the blade works perfectly when the machine is cold -I can lift the machine off the ground with the blade. After 4 or 5 hous of hard working with no reduction in function it suddenly doesn't go up or down anymore. A local excavator tech suggested I pull the drain line off the top of the center joint put a load on the blade and check for bypassing oil. He said if there was excess oil here then my center joint seals were the problem. I did this when it was cold and as I suspected got nothing. Next time the machine gets hot and the problem shows up I will check this again. In the meantime I'll try to do a pressure test. I would think if my rotary seals were going I would start to see tracking problems or a reduction in travel functions but when this problem shows up the travel funtions are perfect. The cylinder tech person I talked to said if the ram seals were bypassing it would be worse when cold and probably improve as it gets hot.
Now that you say the problem all of a sudden comes up. i would say it would not be the centre joint or cylinders. Check to see if this model takes the blade oil and feeds it into the main system when not operating the blade. Some of the smaller machines do this. There could be a problem there. I don't have the schematic in front of me but think I have one at home. A sudden loss of oil from a gear pump does not sound feasible.
The blade circuit has it's own pump and is separate from the main circuit. The main circuit has a computer but the blade circuit has no computer -just pump, valve, rotary and ram. The only system relief valve is on the control valve which seems to be OK. According to my manual this control valve has a "lift check poppet" on the side of the valve--anybody know what this is for? -- Could this be sticking?
Hi, I am no expert but my ex60urg was doing the exact same thing but on rearward tracking to LH motor. After the advice I received on here I did the relevant tests to eliminate some items FOC which then pointed me to the centre joint. I have just serviced the unit & the seals were worn & 3 very badly. My ex60urg has done similar hours to yours. I plan to refit the unit this weekend. Hopefully its fixed my problem! If you attempt the centre joint it not expensive but its a very dirty job. Prepare to be covered in hyd oil!
Good call on the centre joint ken, never clicked with me about it but i guess it could be it also! Id def check theses items first of!