Changing hyd fluid--what about the fluid in the FEL?

Soundguy · Aug 4, 2006

IMHO.. that is what i would do ( have done ).

Change out with clean oil and make up the difference incrementally.

Luckilly I deal with machines that have a large hydro fluid capacity. Even if the implement holds 8 qts.. It's still real dilute compaired to the 48 qts in the machine.. then if you do a flush with cheap clean oil. you gotta figure you have probably dumped up to 4 qts of the bad out..... the rest I chalk up to the filter ( should catch any big pieces.. etc )... .. etc.

soundguy

daTeacha · Aug 5, 2006

Again, the caveat here is that whatever you put in there should meet the specs called for by the tractor manufacturer. What are the contaminants that show up, anyways?? Engine oil gets some combustion by products, and I suppose there is a certain amount of water that gets in sooner or later, but what else is there? Just microscopic bits from wear, stuff that sticks to the pistons when they retract, hose lining material or what? I just wonder where it comes from if the system is sealed.

Soundguy · Aug 5, 2006

I don't think the system is sealed.. I see -many- units with breathers.. meaing microscopic dust particles.. moisture, degrading materials like you mention.. hoses and metalic particles.. etc.

Soundguy

neverenough · Aug 5, 2006

Fluid in attachments is of little concern, unless you have contamination issues. A retracted cylinder holds very little fluid compared to an extended cylinder. As long as you retract the cylinders, like you should, when you disconnect an impliment, that small amount of fluid will not matter much. This is why it is important to retract cylinders before checking hydralic fluid levels. If you extend the cylinders on your attachments, then check your fluid level, you will get a false low reading. When you retract everything, you could end up way over full.

daTeacha · Aug 5, 2006

Doesn't that depend on cylinder design? Some have ports at both ends, pressure both ways, so I presume they are full no matter what position the piston is in. I'm pretty ignorant about hydraulics, so I could be way off on this one. If so, don't be too harsh.

HTWT · Aug 5, 2006

A cylinder will have fluid in it when it is extended or collapsed, but when it is collapsed it will hold less fluid because the cylinder rod will fill up some of the space inside the cylinder.

Soundguy · Aug 6, 2006

The volume of oil in the cyl holds true for what you say when looking at a SA cylinder. If you are talking DA, then there is still a significant amount of oil in the cyl.. minus the volume of the piston.. etc.

It is not always feasable to 'always retract cyls like you are suposed to.'.. depending on the implement or loader design.. or power steering setup.. leaving some piston rod out may be inevitible.

Also.. some tractors instruct you to check the oil sump with all cyls' -extended-. Ford is like that. There is extra room in the hyd sump for quite a bit of oil. In those cases it is better to be extra full ( to a point ).. than way low. If you get too low.. you can have pump cavitation and starvation issues, improper cooling, and open suction lines when on hills.. All my ford hyds say to check with all cyls' extended, just for this reason. In my manuals, there is also instructions that say that up to XX qts can be added tot he sump to ensure proper oil level with cyls extended.. etc.

For instance.. on my NH tractor.. the oil sump shows full at 16.5 gallons.. You can use implements that have a 4 gallon capacity without making up for the oil.. .. alternately, you can add up to 15.5 g of oil to bring the oillevel up to full, with all cyl's extended... that means that sump is running a little less than half full normally... and can operate at 95% full whn used in an application where your aux hyds are using/removing 15-19 gallons of oil from the sump..etc..

Soundguy

neverenough said:
Fluid in attachments is of little concern, unless you have contamination issues. A retracted cylinder holds very little fluid compared to an extended cylinder. As long as you retract the cylinders, like you should, when you disconnect an impliment, that small amount of fluid will not matter much. This is why it is important to retract cylinders before checking hydralic fluid levels. If you extend the cylinders on your attachments, then check your fluid level, you will get a false low reading. When you retract everything, you could end up way over full.

5030tinkerer · Aug 6, 2006

Is there an option like on automotive transmissions on cars where you can disconnect the return hydraulic line that (in the case of cars) goes back to the radiator and then add new fluid back in as the old fluid gets pumped out? I was astonished to note the amount of truly black and disgusting fluid that came out of my power steering system when I went this same route.

gizmo · Aug 7, 2006

If your implements have quick connects, I would make up an open hose section to attach to the implement lines and just cycle the cylinders manually to drain them. For the loader you can connect an open line to the filled side and use the tractor hydaulics to operate the cyclinder in the direction required to drain it.

Personnally, I am not convinced that it is really necessary to change hydraulic oil at the intervals recommended.

Soundguy · Aug 7, 2006

I guess you could always send in a sample for oil test and see what your hydro oil looks like at 'interval' time. Then decide from there on future changes.. I.E. see what contaminates are there.. metalic particles, and moisture / addative package.

IMHO.. I like to drain mine at interval just to be on the safe side.

It's too much money to risk 1000$ hydro pumps and 700$ spool packs and 700$ qd/relief setups for 80$ of oil.. etc.

Soundguy