problem started when i got the machine home. ex will do fine for a while maybe 30 min then the hydralics get week or slow. the machine wont move by itself i got mad go do something else come back 10 15 minutes later crank it up and it will dig fine run for about 20 minutes and the same thing again. did that about four times that day the 5 time i left it came back 2 weeks later and still the same thing but now machine wont dig at all cold . if you stick out as far as it will go and bring it back in fast and stop suddenly with boom up in position the boom will move up slightly. track will travel but very week both at the same time one track at a time will not move . can hear fluid bypassing when any motion is attemp i think a relief valve is stuck somewhere letting the fluid bypasss but i dont know where to look downloaded shop manual but not very helpful the pilot filter canister started to leak . sometimes the machine would be very strong or seem to be
change the hyd filters and oil first, then i would say there is a valve sticking on the valve chest, or you have a major blockege, ie a filter collapsed or dirt in an element.
the oil and filters are ok just replaced the pilot pump filter a month or so ago went to the farm today play with the machine unplug sensors one at a time no difference still wont power itself scared to let the boom hit the ground may need to use the d4 to push it on the loboy hope someone will give a clue to what is happen i didnt get a chance to try to find the main relief valve i think it may hold the answer i tried to pull the pilot pump spool out yesterday i didnt have any pliers left spring out and powered up but it still wouldnt come free but it did move out as far as the spring would have ever let it so i put it all back together still same problem the oil doesnt smell the greatest but its not burnt can find very small or fine metal in filters but i am not worried about it, like gold dust .still hear fluid bypassing before a cylinder reaches full stroke it has to be a relief valve somewhere just dont know where to start and dont really have the extra tim e need a good mechanic hitachi john deere 160 in desoto county mississippi or memphis area anyone need work?