Hitachi EX27u Low Pressure ?
Posted: Sat Jan 13, 2018 1:16 pm
Hi Guys,
I am in the middle of 'fiddling' with a mini digger I bought last summer, bought it 2nd hand in France, I knew at the time there would be lots of maintennance to bring it up to spec - and wasn't wrong.
So Far I have cleaned it all down so it is OK to work on, then drained all the emulsion that was passing for Hydraulic oil out of the tank, changed all the hydro filters, cleaned the suction filter and replaced it, replaced 4 pipes with new (2 x pecker and 2 x Boom)- serviced the track tensioners and idler wheels and got the tracks back on myself (quite easy surprisingly) and have been running the engine/pump slowly over the past week and exercising the rams - ran it up and down inside my woodyard (too wet outside) and the tracks seem really good now - lost the horrid squeak that was present when I bought it - even managed to get the m/c into "high speed" and seems good.
So, my current issue: To me it seems to be a pressure related problem that has me scratching my rear: The following tests are done with m/c at half revs.
The dozer blade will no longer lift the m/c of the ground OR the Boom will not lift the m/c off the ground; depending on whether the dozer blade is up or down
IF - the dozer blade is down, the m/c is unable push out the boom ram, if I lift the blade up -then- I get full action (pressure !! ) to lift the m/c up,
IF - the boom and dipper are all retracted in, this makes NO difference to dozer.
The dozer blade will, slowly lift up the m/c at half revs, if I push the lever, release push again etc. i.e. sort of teasing it up.
A mate of mine suggests replacing the seals inside the dozer ram !!! he is a supposed hydraulic expert and has in the past suggested putting washers behind the control leavers on my cherry picker to "boost" the pressure - So not a lot of confidence in his suggestion. He does however have hydro pressure testing meters and Tee's and is willing to help me test the system pressure.
Questions
1 Should I just keep on exercising the rams and expect any air in the system to eventually come out ?
2 Should I go around all the pipe ends and bleed them or check for Oil - Air ?
3 Are there any exercising tests I can do that may point at dodgy pump or controller or something?
Sorry to be a bit long winded (as per) but thought it best to layout what i've done first.
Hope some of you are still awake
Best wishes to all for 2018
I am in the middle of 'fiddling' with a mini digger I bought last summer, bought it 2nd hand in France, I knew at the time there would be lots of maintennance to bring it up to spec - and wasn't wrong.
So Far I have cleaned it all down so it is OK to work on, then drained all the emulsion that was passing for Hydraulic oil out of the tank, changed all the hydro filters, cleaned the suction filter and replaced it, replaced 4 pipes with new (2 x pecker and 2 x Boom)- serviced the track tensioners and idler wheels and got the tracks back on myself (quite easy surprisingly) and have been running the engine/pump slowly over the past week and exercising the rams - ran it up and down inside my woodyard (too wet outside) and the tracks seem really good now - lost the horrid squeak that was present when I bought it - even managed to get the m/c into "high speed" and seems good.
So, my current issue: To me it seems to be a pressure related problem that has me scratching my rear: The following tests are done with m/c at half revs.
The dozer blade will no longer lift the m/c of the ground OR the Boom will not lift the m/c off the ground; depending on whether the dozer blade is up or down
IF - the dozer blade is down, the m/c is unable push out the boom ram, if I lift the blade up -then- I get full action (pressure !! ) to lift the m/c up,
IF - the boom and dipper are all retracted in, this makes NO difference to dozer.
The dozer blade will, slowly lift up the m/c at half revs, if I push the lever, release push again etc. i.e. sort of teasing it up.
A mate of mine suggests replacing the seals inside the dozer ram !!! he is a supposed hydraulic expert and has in the past suggested putting washers behind the control leavers on my cherry picker to "boost" the pressure - So not a lot of confidence in his suggestion. He does however have hydro pressure testing meters and Tee's and is willing to help me test the system pressure.
Questions
1 Should I just keep on exercising the rams and expect any air in the system to eventually come out ?
2 Should I go around all the pipe ends and bleed them or check for Oil - Air ?
3 Are there any exercising tests I can do that may point at dodgy pump or controller or something?
Sorry to be a bit long winded (as per) but thought it best to layout what i've done first.
Hope some of you are still awake
Best wishes to all for 2018