Hydraulics questions again :)

[Wa11banger]

Hello fellow TBN peoples.. I am back with hydraulic questions again.. I know crazy right? I will be starting a build (maybe rebuild ) thread here shortly for a new toy I just bought but I need some hydraulic assistance to get there first.

I just bought a Dig-It tow-able backhoe! I know, I know, there will be haters but lets not get into why or why not to own one. I am fairly excited that I get to work on a new toy and could care less if another thing can do it faster or better than the thing I just bought. Please stick to the topic at hand and that is the hydraulic questions I am at a loss for.. I did some searching on TBN and I don't know if I didn't use the proper key words but I couldn't find an answer for total empty system or how to properly get wrong fluid out of one completely so here goes.. I hope I am not repeating.

I bought the Dig-it from someone that really didn't know anymore than I did about hydraulics and apparently cant read warning labels either and he filled the hydraulics up with universal hydro fluid. There is a 4 inch sticker right next to the filler that says fill with 10w-40 motor oil..

Can anyone guide me to the proper way to bleed the whole system? it was run quite a bit like this but I do not believe it is working to full potential.

Step 1
Drain huge reservoir.. Check! got that far

Step 2??
how in the world do I get it out of the great number of valve bodies and the the cylinders? That is where I am lost. I thought about going circuit to circuit and loosening the retracting return line then tightening and working on the extending return line etc etc.. But I wanted to make sure I was not making more work for myself than necessary. Also thought about using air pressure to blow all lines clean first and see if I could get the pump to refill all of them but wasn't sure having a completely dry system was something I needed special tools or pressurized system to make work again.

Any and all help is greatly appreciated and I look forward to the responses..


JJ, Greg, and Rich I know your out there

 

[J_J]

You could use most any mineral based hyd fluid for your climate and it should work.

Even ATF would work.

Power-Trac owners have been using engine motor oil in our machines for about 20 years and works very well.

As far as bleeding, just cycle all the cyl about 10 times, and the air should purge itself.

Put a hyd gage in the hyd system and tell us the relief pressure.

Are you using a 10 micron return filter?

 

[Wa11banger]

Thanks for the reply JJ.. Just so I don't go messing it up.. You said as far as bleeding just cycle about 10 times and the air should purge itself.. Is that answer in reference to my completely opening the system and blowing all lines clear or just if I break open any singular spot.

it has a pressure gage on the filter housing.. I have to replace the lens as the dial is barely visible through the lens. But will report out once I get it back up and running again.

 

[J_J]

Any time you open any part of the hyd system, air might enter the hyd system, and the hyd system needs to be purged.

Symptoms of air might include mushy operations, erratic operation, slow, jerky, no function, etc.

 

[Wa11banger]

But if I open it up completely, perform a full purge of all lines will it recover from that? Starting from just air in lines and cylinders and fresh fluid in the reservoir? Or is there a priming procedure to do first. Sorry for the hydraulic ignorance but even google has been no help in my research. Again, I appreciate the advice

 

[muddstopper]

I dont know how much oil the machine holds, sounds like a small piece of equipment. To change fluids in the past, I have drained the tank of all fluid. Fill tank with new fluid. Then remove the return line from the tank and place hose end into and empty container. Crank machine at idle and watch the oil for a color change as it is being pumped into your empty container. As soon as the oil changes color, shut off machine and reconnect your return line hose. Now change your filters and your done. Oil is changed and only takes a few minutes to do it. I have done this on machines that hold 2-300 gal of hydraulic fluid and on machines that only hold 5 or 10 gal of fluid. Once I did a oil change over from Rando68 to dextron3 on a whole fleet of equipment. About 50 machines. It took 3 men all day to get the job done, but our bosses where surprised we where able to get it done that fast. Of course we had a engine driven pump to suck the tanks dry and refill with new oil, and a tanker truck to pump the old oil into.

 

[Fallon]

Just fill up the tank & run it, the pump will push fresh oil into lines & push out the air. Run the cylinders in and out a dozen times & the oil will end up purging out the air in the work lines & cylinders.

 

[Wa11banger]

Thanks for the info all.. its a smaller machine for sure but not as small as most think its as big as a compact car.. It's bigger than my kids dodge neon was.

Muddstopper, If I had to guestimate I'd say the reservoir holds between 12 and 15 gallons and as new as I am to this stuff I couldn't begin to guess what the rest of the system holds. I am familiar with the purge process you described but I assumed that only worked on single sided hydraulics. Maybe I misunderstand how it works. My thought on it was that once full, the hydraulic fluid only went back and forth in the system. I didn't think it was a recirculatory system where fluid in the cylinder would make it back to the reservoir.

Fallon, thanks for the input, I wasnt sure that if the system was completely dry that it would be able to refill the lines and cylinders without special support equipment

 

[aczlan]

I would just use it with the UTF in it and change over to 10W40 next time you change the oil...

Aaron Z

 

[davedj1]

I would just use it with the UTF in it and change over to 10W40 next time you change the oil...

Aaron Z

I would do this also, just run it as is.