mini excavator with weak drive motor

[hydrogeo]

Hey folks, my father has a grey market Hitachi EX55 UR excavator (~12,000lbs). The machine has around 5000 hrs on the meter and seems pretty tight overall. There is plenty of digging power, but the track on the right side seems to really lack power. The machine had new rubber tracks installed shortly before he got it about a year ago, and neither side seems too tight. If you move the machine forward on level ground it pretty much tracks straight, but if you try to push anything with the blade or turn too hard the right track stalls. Can anyone point me in the right direction for diagnosing and fixing the problem?

Also, I would like to change all the fluids in the thing (my dad is a "it's got oil in it so why bother" kinda fella) but have no clue what goes in the drive motor gear boxes. I also assume there is a gearbox for the swing motor, no? Anything else besides the engine and hydraulic oil?

Thanks in advance for any input.

 

[hydrogeo]

Hey folks, my father has a grey market Hitachi EX55 UR excavator (~12,000lbs). The machine has around 5000 hrs on the meter and seems pretty tight overall. There is plenty of digging power, but the track on the right side seems to really lack power. The machine had new rubber tracks installed shortly before he got it about a year ago, and neither side seems too tight. If you move the machine forward on level ground it pretty much tracks straight, but if you try to push anything with the blade or turn too hard the right track stalls. Can anyone point me in the right direction for diagnosing and fixing the problem?

Also, I would like to change all the fluids in the thing (my dad is a "it's got oil in it so why bother" kinda fella) but have no clue what goes in the drive motor gear boxes. I also assume there is a gearbox for the swing motor, no? Anything else besides the engine and hydraulic oil?

Thanks in advance for any input.

 

[Dirthog]

first thing I would do is get a pressure gauge and check travel pressure should be able to check it on the main control valve and also someplace on the motor the other thing is there is a drain line on the motor that goes to tank check how much oil you have with the motor stalled and then do the same on the other side if there is a lot more leakage on the weak side the motor needs repaired

 

[Dirthog]

first thing I would do is get a pressure gauge and check travel pressure should be able to check it on the main control valve and also someplace on the motor the other thing is there is a drain line on the motor that goes to tank check how much oil you have with the motor stalled and then do the same on the other side if there is a lot more leakage on the weak side the motor needs repaired

 

[hydrogeo]

Thanks much! Regarding the pressure gage, do you just use a standard pressure gage tee-d into each line using a short piece of hose or are there auxiliary pressure ports for checking pressure? My familiarity with hydraulics starts and ends with my Kubota, so please forgive my ignorance.

 

[hydrogeo]

Thanks much! Regarding the pressure gage, do you just use a standard pressure gage tee-d into each line using a short piece of hose or are there auxiliary pressure ports for checking pressure? My familiarity with hydraulics starts and ends with my Kubota, so please forgive my ignorance.

 

[Dirthog]

yes just any gauge for oil but you should have one for around 5000psi there should be a plug in the motor in fact I think one each for foward and reverse.

 

[Dirthog]

yes just any gauge for oil but you should have one for around 5000psi there should be a plug in the motor in fact I think one each for foward and reverse.