Hi everyone.Maybe someone can help me.I have a Hitachi ex60 and I haven't had any problem for a couple of years.But now I am starting to have a problem with the steering.When the oil is cold,no problem except it seems to always steer a little to one side.But as soon as the oil becomes hot I lose almost all power to the tracks and it is very hard to steer,but again I have a little more power on one side.All the rest of the hydraulic work fine. Any ideas??Is it the pump or some adjustment I can do? Thanks
Hi DMC The symptoms described sound typical of leakage within the swivel joint or rotary coupling in the centre of the machine that transfers hydraulic flow between the upper and lower frames. Leakage between the ports is generally accompanied by high temperature... maybe try checking the temperature by hand to see if its getting significantly hotter than adjacent control valve and hoses.
Thanks Wulf.I will use it again in the next day or two and I will check that then.If this is the problem,is this hard to fix?Thanks again.
Remember to work the travel motor circuits for some time to get the oil flowing through the coupling before checking temperature. No it shouldn't be a big job to disassemble and replace the seals. Generally there is a snap ring or a retaining plate under the cover that holds the static and rotating elements together but I would consult the parts book to be sure.
Still haven't had the chance to try it and now I have to go out of town for a couple of days.But, I was wondering if the hydraulic oil I have in the tank is maybe too thin.I put #42 oil in there not too long ago, Is this too thin? What is the correct # of oil for these machines? Thanks
It could certainly have an effect on leakage if its too thin. If you don't have an owners manual with oil specs my advice would be to check with Hitachi and use what they recommend or get a vendor to supply an equivalent.
Will I had the chance to use it again today.After about a hour I checked the pipes and hoses with my hand to see if they where hot.There are 3 pipes going to the motors that turn the tracks,a small one on the top and 2 bigger ones on the bottom, the top biggest one does seem to be a little hotter. I just reread your post and I dont think these are not the pipes you are talking about. Where exactly are the pipes you mean?Another guy told me to check my return,to see if there is any pressure there.But I am not sure which is the return.Any help will be great.Thanks
Hi DMC The symptoms you are describing, hard to steer & steering to one side - and the rest of the hydraulics are fine, point to the centre swivel (rotary manifold) as Wulf says. This swivel is what allows the high pressure oil to be sent to your travel motors from the top of the machine to the bottom without hoses. Inside this swivel is a centre post with lans and 5 - 7 seals, depending if you have a blade on your machine or not. Most hydraulic shops can rebuild this for you quite economically - $500 - 800. They will push the centre post out, rechrome it (the seals wear grooves in the lans with use) back to factory spec, put new seals in it, push it back together and your back working. If it was a hydraulic pump problem you would see other problems besides steering. Your EX60 has a double bent axial pump setup that feeds a control valve with 2 sides to it. The rear pump feeds the LH side of the valve - LH Travel, Auxillaury,BoomII,ArmI and Swing functions and the front pump feeds the RH side of the valve - RH Travel, Bucket,BoomI & ArmII functions. Your lines on your travel motor are : small line on top is a common case drain line, the top line is Reverse and the bottom is Forward.
Thanks for the advice. I will remove this and get it rebuilt.Thanks again.
Hi DMC... This is what they look like and obviously its in the centre of the machine with hoses going to it.
Thanks again.Now I know what to look for.I am still working with this machine but I should get the chance to remove it in the next couple of weeks.Will let you know how it turns out.Thanks again you guys are great. :notworthy :notworthy
low power in tracks you should check the pressure in both travel sections also check the bypass on both travel motors they will be the smaller of the lines going to the motors and back to tank there should be very little oil draining back to tank. The swivel in most of these machines is very trouble free think we have only had 2-3 go bad on all the kobelco's we have sold and there were a lot.