Evening!!...New to the site here...I have a 1986 hitachi EX60 3154 original hours on machine!! I am the 3rd owner, the problem i am having is hydraulic oil getting hot after about 20 minutes of use then the hydraulic light comes on and then there is this bad screetching noise of some sort but still operates just operates slower and some lose of power ...noise is coming from valve bank and sounds like oil bypassing...main pump has been replaced and has plenty of pressure..ive had 2 people look at it and no 1 to find or fix problem....been completely service..new filters and hydraulic oil.. twice after a blowed hose drained tank also all pressure valves removed and new Orings...no signs of metal in tank anywhere...now i know its hard to figure out what the problem is just describing it on here but maybe someone out there might just point me in the right direction or something...thanks for reading!!:Banghead
forgot to add that the noise only starts when u start working it really hard and putting everything under pressure!!//Thanks
Main relief is probably faulty or the valve is cracked. The problem is only exaggerated now that you continue to use it
I will check that in the AM!!..Thanks
I check the main relief and took it apart looked at it and put it back in and turned it all the way down and all the way back up and no difference in anything!.
You have a pressure drop somewhere, use a infra-red thermometer to find the hottest spot in the system. That is where your problem is
mike we have used a temp gun everywhere and cant find anything out of the ordinary!..we found out that the noise was coming from the pump after it beat the brass off the pistons so then we did a complete hydraulic tear down and cleaned the system out and started over ..after about 2 minutes of playin on it I get a bad noise from the pump!!...I checked the main relief valve and it was clean and no cracks and the john deere place said it looked good to them!!..idk what else to do!!
mike when the noise starts it seems the system is building pressure and it has blowed the pump front seal out twice JD says it was good and looked good but im thinkin i need to replace it anyways...i have put so much money in it now ima have to keep it!!
Blew the seal out out of the piston pump? Meaning case pressure too high. Meaning the drain line is plugged or the rotating group is shot or the pressure is too high and the valve plate is seperating from the barrel.
What is the pressure between the outlet of the pump and the control valve at low idle and high idle? What is the pressure between the outlet of the pump and the control valve with bucket stalled?
idk what the pressures are mike..the JD place set all the pressures and then it started that problem..i took it to them to set the pressures cause i thought that was why it was making the noise and i got it home and played on it and that happened twice so it sits in the yard!!..
the system right now is spotless and clean with fresh fluid!!...i have completely took the hydraulic system out and tore everything down and blowed air through everything //pump cooler line..control valve..etc..etc..What do you mean by rotating group is shot??...and valve plate seperating from barrell??
ok i know the valve plate that your talkin about now...all of that in the pump is new and still looks new...if i operate the machine to much it will make a bad noise in the pump and beat the brass off the pistons so its just sittin here!!
ok ive done alittle research on what u just said...i know that my pump and all thats in it is good..I think that the case pressure is too high!!..i sent you a PM