We recently got two letters from two different viewers on our YouTube channel, both asking whether you can ruin your tractor’s hydraulic system by putting a foreign attachment on the tractor. In other words, if you connect a hydraulically powered attachment from somewhere else to your tractor, is there a risk of damage?
The first viewer said he’s fairly new to tractors and still learning, but had a question he couldn’t find an answer to anywhere.
“I have the basic implements, including a grapple,” he said, “but obviously I cannot buy every attachment I will ever need. It makes more sense to rent the attachments as needed.”
He continued to explain that he had concerns about using a rented attachment with hydraulics.
“When you connect it to your tractor, you’re blending your tractor hydraulic fluid with whatever’s in the cylinders hoses and hydraulic motors on the rented attachment. You have no way of knowing what fluid is contained in that attachment, or what kind of contamination might be contained in that fluid. Am I overthinking this problem or is my concern valid?”
The second viewer went in a little different direction. He said he’s going to borrow an implement from a friend and wanted to know if attaching it will contaminate his hydraulic fluid system.
The Answer is Technically Yes. But You Can Fix It
Well, the answer to both questions is technically yes. Whatever hydraulic fluid is in those cylinders and hoses is going to migrate through your tractor and become a part of your hydraulic fluid. Now, is that a reason not to do it? I don’t think so, but I decided it would be useful to calculate how much hydraulic oil is in a typical attachment and measure that against the total oil in your tractor’s system. I includes fluid that’s going to come back into your tractor hydraulic system from both the cylinder and the hoses.
For this experiment, I used my tree puller attachment made by Precision Manufacturing in Sedalia, Missouri. I sell them on my website and it’s something I’ve owned for maybe two or three years. I use it to pull up undesirable trees, rose bushes, thorn trees and other pests I find back in my woods. We’re going to use today as an example of about how much oil is contained in the hydraulic system of an attachment like this.
The Tree Puller Has a Fairly Common Hydraulic Cylinder
As it happens, the tree puller has a 3”x8” hydraulic cylinder, which is fairly common in the ag industry. When I checked some comparable ones online, I found a used one for sale with a three-inch bore by eight-inch stroke hydraulic cylinder. The specs indicated that this particular hydraulic cylinder had 0.98 quarts of oil in it. There’s four quarts in a gallon, which means it’s got about a quarter of a gallon of oil in this hydraulic cylinder.
Now we’re going to calculate how much oil is in the hydraulic hoses, and no, this is not going to be exact. If you tend to be anal about your volume measurements, you’re not going to like this. But for this discussion, getting a ballpark number will be fine.
Recently, I found a pipe volume calculator online and, of course, this is not a pipe, it’s a hose. But it should help us get a pretty good idea of how much oil is in the hoses.
First off, we’ve got to know what the inside diameter of the hose is in inches. The hose is actually a 3/8” hose, so if I remember my math right, I take 3 and divide it by 8 to determine the size of the hose’s inside diameter. Turns out it’s 0.375”.
Of course, my tree puller has two hoses on it: One to extend the RAM and one to retract the RAM. One hose is 89 inches long and the other is 99 inches. When I add them together I’ve got a total of 188 inches of hose. I divide by 12 to find out how many feet, and it looks like it’s 15.66 feet of hose.
Once I’ve entered my values on the pipe volume calculator, I find that I’ve got 0.09 gallons of oil in those hoses. Okay, that’s not exact but it’s close. I can safely figure I’ve got almost a quart of oil in the cylinder, as well as about a tenth of a of a gallon of oil in the hoses. So that would be a total of 0.35 gallons, or pretty darn close to a third of a gallon of oil that’s going to get into my tractor if I borrow or rent this attachment.
Now I know that the total volume of my tractor hydraulic oil is 9.6 gallons. The attachment hydraulic oil came in at about a third of a gallon, so we’ll say that I’ve got .35 gallons in the tree puller. I’m going to divide that by 9.6 ( the total amount of hydraulic oil in my tractor). That means I’m putting about almost 4% contaminated oil, or oil of unknown origin, back into the tractor. That’s a pretty negligible amount, so the bottom line is this: With such a small volume of oil coming out of the hydraulic attachment into the tractor (and the fact that your tractor has some kind of hydraulic filter to catch any contaminants), I think your danger is really low.
Still Concerned? Try This
If you’re still concerned about contamination, there are a couple of things you can do. First, you can change your hydraulic filter more often. And then you can change the oil after you use rented or borrowed attachments. Just get it all out of your tractor and put new, clean oil in.
Honestly, I don’t worry as much about hydraulic oil as I probably should. My father was not a big maintenance guy and I the fruit didn’t fall too far from the tree, I think.
One time when I was working at the dealership, my dad called me and said his three-point quit working. I said, Well, Dad, when’s the last time you changed her hydraulic filter?”
And his answer was that he didn’t think this tractor had a hydraulic filter. Hmmm… I’m pretty sure it does have a hydraulic filter, Dad, so you might try changing it. I suggested that, and he bought a new filter and changed it, along with the oil, and the three-point started working again. I guess that filter was completely clogged.
We sold that tractor after he passed away, and as far as I know it’s still running well. This is all to say that hydraulic systems are pretty forgiving in terms of contaminants.
Attachment Owners Generally Want Them to Last
Most of the time, anybody who owns attachments aims to make them last as long as they can. They work to keep their tractor hydraulic systems from getting contaminated. It seems to me that rental yards, by and large, will do this. If they get a hydraulic powered attachment back and it’s all dirty around the plug-ins – the couplers – they’re going to clean that off and make sure it doesn’t get in the system.
But if you’ve got a neighbor who just lets dirt build up around the hoses and then plugs them in with dirt on them, you sure don’t want to borrow his attachments. However, most people are pretty good about keeping those areas clean because they realize dirt going in there is going in into the tractor’s hydraulic system. And we know that’s not good.
So to sum it up, if it were me I wouldn’t worry about it. If you’re going to be using a lot of rented or borrowed attachments, be sure change your filter and/or oil more often and it should be fine.