I've got an old Hitachi UH083LC that I use in my mining operation. Been a good old machine but the pressure in the oil tank seems a bit high. Can't find what the pressure is suppose to be in the service manual. Anyone know what the pressure range should be ? Thanks!
I don't recall the Hitachis, the Mitsubishis had a tank pressure gauge with the numbers marked on the green section if I remember correctly, and some decals either on the tank or regulator. Should be a radiator type cap on their that will bleed pressure if it's too high.
Thanks. The machine has a pressure gauge on the panel but it never seems to move so I don't think it ever worked since I've had it. It does have some sort of pressure relief fitting on the top of the housing but again I'm not sure it's working. I stuck a pressure gauge on it and the pressure goes up to 40 PSI in the tank.
The old 200 series Cats had at least 40 psi tank pressure, I'm sure. I've never measured it, but I'm sure it was at least that.
mitch .... thanks for the input. Well maybe 40 psi isn't unreasonable then. Just seems high.
Sounds high to me, I thought the old mitsis were around 20-25 psi, but then the Hitachis could be anything, i just don't remember. The mitsis had a regulator along with the governor for the compressor, I can't remember the Hitachis because we never had any problems with them.
1 bar pressure is all thats required. Now that pulling stuff out of an old brain. I operated the first one sold into Australia and New Zealand. To my mind they were the best model 20 toner Hitachi ever made, did 1100 hrs in 4 years with no problems except a lack of gravity on one track one time. ops
Tones ... thanks. That sounds more reasonable. Guess I'll stick a new 15 psi regulator on it and see how she works. I've got an EX200 LC-3 also but I sure like running the old girl, even though she has about 15,000 hrs now.
If the pumps aren't whining at 15 psi it'll be fine, that's what the pressure does, supercharge the main hydraulic pumps.
My last post should read 11000hrs. If I remember rightly there should be a pressure relief valve on the top of the tank near the filter cap or maybe even on the cap itself. It's a bugger trying to go back into the noggen 30+ years
Yup .. there is a pressure relief valve but I don't think it's working because I never hear it venting. The reason I was suspicious and stuck a pressure gauge on it is I started getting leaks where I shouldn't. Both finals are getting hydraulic oil in them now and the pump gearbox is getting hydraulic oil in it.
I hope it hasn't damaged the seals. Has the pump gearbox got a breather on it?
Yes, gearbox has a breather and after about 12 hrs of running oil starts spitting out the breather. I have to drain it and put fresh 90W in. I stuck a small ball valve on the tank and leave it cracked a tad to relieve some pressure. Hopefully it didn't blow any seals and this will solve the problem for now.