Hydraulic lesson learned today

[larry_g]

I have a large 14k dump trailer. This trailer has its own battery powered hydraulic system. A year or so back The battery was way low and when lowering the bed it over run the pump and forced hydraulic fluid out the tank vent. So I topped it up with some AW-46 hyd fluid I use in a lot of the rigs here.

Well yesterday I made a dump run and the bed would barly lift, but it got up enough to dump. Coming down it puked fluid from the tank again, on this time it looked like thick chocolate milk.

(picture from internet, mine is similar but double acting.)

I pulled the power unit and removed the tank and found the filter clogged with goo. It was obvious that the fluid was contaminated. Further checking I surmised that the original fluid was a water based 'environmentally friendly' fluid and my adding oil based fluid last year gummed the system up.

So be forewarned; Know what the fluid in the system is before adding more. Last year I called the manufacture and the sales place and reviewed the literature with the trailer and nothing was specific what was in my unit.

Any way I had to flush the system and it is now AW-46. All is good now.

lg
no neat sig line

 

[Pathfinders]

Good tip. Thanks

 

[matt_i]

Any kind of water in an oil based system is bad. It is emulsified into milkshake very fast by gear driven pumps.

The one good thing is the mix seems to have enough lubricity to keep going for awhile without a total friction meltdown, and hopefully is checked/changed by an astute user like you before things get really far gone.

 

[Bondo]

Further checking I surmised that the original fluid was a water based 'environmentally friendly'

Ayuh,.... Water based hyd. oil,..?? Never heard of such a thing,....

I'd sooner think the system got water from somewhere else,....

 

[manwithtools]

Ayuh,.... Water based hyd. oil,..?? Never heard of such a thing,....

I'd sooner think the system got water from somewhere else,....

Not as uncommon as you might think. I've had to use it in some solar applications in the desert where the local governing agency would not allow petroleum based fluids. Not saying it's the case in this instance, but it does exist.

 

[larry_g]

Ayuh,.... Water based hyd. oil,..?? Never heard of such a thing,....

I'd sooner think the system got water from somewhere else,....

Quite a few non petroleum based products out there. The trailer system is enclosed in a tool box on the tongue so I'm perty confident that no water got in there accidentally. Unless some one sabotaged it, which is unlikely because it is not left out often.

lg
no neat sig line

 

[rburke65]

Not surprised as THEY......Gov. ......are trying to make everything they can from a latex base.

 

[TheEquineFencer]

You can use some types of Vegetable oil for hydraulic fluid. I worked for local Government a while. My superintendent changed all the in ground lifts to Veggie oil. Later we had an in ground leak and some a-hole in the shop called EPA on him. They came out and saw it was biodegradable Veggie oil and told him to have fun fixing the leak, he didn't see a violation. But it has to be changed much more often or it goes rancid...Yes it get's bad...

Old post I know...

 

[tarmy]

Great tip. I just bought a 14k dump trailer too. This thread got me to check with the dealer here in Commiefornistan...sure enough...water based. He is required to fill with it.

Guess what I am doing this weekend with the 2 gallons of normal hyd fluid I just bought...

Thanks OP...

 

[The Cobbler]

good to know. thanks for the tip

 

[mikepelchy]

I lot of pumps of that style will call for an AW-32, ATF or bio-degradable oil. On the machines that I work on that use similar pumps, I typically use JD low-vis hy-gard which is am ISO32 oil.

I do know that when mixing a non-zinc based hydraulic fluid with a zinc based hydraulic fluid, lots of bad things can happen. Whenever I end up taking oil samples and sharing the results with the factory, they often question what type of oil is used (we can't control what our customers put in their machines when they blow a hose 100 miles from the nearest town) and they will always talk about mixing of oils causing hydraulic filters to plug and other various issues.

 

[larry_g]

Great tip. I just bought a 14k dump trailer too. This thread got me to check with the dealer here in Commiefornistan...sure enough...water based. He is required to fill with it.

Guess what I am doing this weekend with the 2 gallons of normal hyd fluid I just bought...

Thanks OP...

I can say that on my system it took near 10 gallons to flush and refill the system. I would not have changed it from the water based system if I had know that is what in there from the factory. Nothing wrong with the enviro systems, we had that fluid in most of the hyd systems I worked with in the plant including the fork lifts. The thing is just don't mix them with oil based.

I'd say don't fix what isn't broken.

lg
no neat sig line

 

[LifeLongWNYer]

I wonder what the manufacturers of garage lifts are using.



.

 

[chris142]

I topped up our 2 post lift at work with atf. It caused foam with whatever fluid was already in there.made a mess.

 

[Richard Cranium]

Thanks for the heads up, never had thought about it before.

 

[tarmy]

I can say that on my system it took near 10 gallons to flush and refill the system. I would not have changed it from the water based system if I had know that is what in there from the factory. Nothing wrong with the enviro systems, we had that fluid in most of the hyd systems I worked with in the plant including the fork lifts. The thing is just don't mix them with oil based.

I'd say don't fix what isn't broken.

lg
no neat sig line

I appreciate this comment. Was it that bad...as in, you may be right. I will be using the hydraulics a few times a year...

If you had a need to continue to flush to clear the system to the order of 10 gals...I may just let it ride.

 

[larry_g]

I appreciate this comment. Was it that bad...as in, you may be right. I will be using the hydraulics a few times a year...

If you had a need to continue to flush to clear the system to the order of 10 gals...I may just let it ride.

It wasn't a bad job to change the fluid. It just took some creative plumbing to draw in fresh fluid while extending the cylinders and catch the flow out in a waste bucket. Then replumb to pump in fresh oil on the retract. Then do it again to get a good rate of exchange. My trailer has two large cylinders that hold a lot of fluid. I might be shy on the 10 gallons, it's been a few years ago.

Any way bottom line of the post is don't mix the fluids. What got me in trouble is the pump/battery failed and in lowering the bed a lot of fluid was forced out of the tank. I just assumed it was common hyd oil and added some back in --> big mistake.

lg
no neat sig line

 

[tarmy]

It wasn't a bad job to change the fluid. It just took some creative plumbing to draw in fresh fluid while extending the cylinders and catch the flow out in a waste bucket. Then replumb to pump in fresh oil on the retract. Then do it again to get a good rate of exchange. My trailer has two large cylinders that hold a lot of fluid. I might be shy on the 10 gallons, it's been a few years ago.

Any way bottom line of the post is don't mix the fluids. What got me in trouble is the pump/battery failed and in lowering the bed a lot of fluid was forced out of the tank. I just assumed it was common hyd oil and added some back in --> big mistake.

lg
no neat sig line

Thank you for the follow up comment as well. I am old enough to learn from other folks experience! Young enough to need to fix something that is not broken...

I will let this one function till failure....and see if I am still alive