Just changed my Hydo oil

Usta · Mar 14, 2011

Changed my hydro oil for the first time with just under 400 hours on the tractor. Changed the hydro oil, hydro filter, and cleaned the hydro screen. I have pulled the screen filter once before but never changed the hydro filter canister. I was getting nervous with all the talk on here about finding metal shaving in the hyro systems screen and filter canister. I looked very close and even played around with a cow magnet but could not find any metal shavings at all.
What really surprised me was how dark colored the old hydro oil was compared to the new oil. The majority of the 400 hours are with hard loader work in the dirt so that may have contributed to the hydro oil heating up and turning dark. Worked the loader real hard last summer.

timswi · Mar 14, 2011

Sounds like you covered all of the bases...I usually change mine sooner, so I can't say what fluid looks like at 400hrs...I'm sure it's like tranmission fluid, gets a little cruddy over time, no harm.

BeezFun · Mar 14, 2011

Usta said:
What really surprised me was how dark colored the old hydro oil was compared to the new oil. The majority of the 400 hours are with hard loader work in the dirt so that may have contributed to the hydro oil heating up and turning dark.

I talked to one of the mechanical engineers at work. He gave me a book with a section on hydraulic oil and strainers that I could almost understand. I think it explains why the oil cracks and changes colors, so I'm not sure the dark color is due to dirt. Here's the text verbatim:

"However, the majority of components of contaminants in working hydraulic systems are not solid particles like ACFTD but toluene soluble resinous matter, as shown in table 2. Resinous matter has polarity and is adsorbed onto metal surfaces. It is sticky and attracts other solid and fiber contaminents which then stick to them. By this mechanism, suction strainers will be clogged.

A suction strainer is actually a full flow filter. Hydraulic oil passes through a suction strainer at very high velocity. This means that both oil and the strainer will be electrified by friction of oil with the strainer. When oil passes through insulated strainers, static electricity will be accumulated on the strainers and the accumulated electric charge will be discharged by sparks. Spark discharge of static electricity will crack oil molecules and produce free radicals. Free radicals will propogate autoxidation of oil and produce polymerized oil oxidation products (resinous matter). This cycle continues, as long as full-flow filters are used in hydraulic systems."

Deano · Mar 15, 2011

BeezFun said:
I talked to one of the mechanical engineers at work. He gave me a book with a section on hydraulic oil and strainers that I could almost understand. I think it explains why the oil cracks and changes colors, so I'm not sure the dark color is due to dirt. Here's the text verbatim:

"However, the majority of components of contaminants in working hydraulic systems are not solid particles like ACFTD but toluene soluble resinous matter, as shown in table 2. Resinous matter has polarity and is adsorbed onto metal surfaces. It is sticky and attracts other solid and fiber contaminents which then stick to them. By this mechanism, suction strainers will be clogged.

A suction strainer is actually a full flow filter. Hydraulic oil passes through a suction strainer at very high velocity. This means that both oil and the strainer will be electrified by friction of oil with the strainer. When oil passes through insulated strainers, static electricity will be accumulated on the strainers and the accumulated electric charge will be discharged by sparks. Spark discharge of static electricity will crack oil molecules and produce free radicals. Free radicals will propogate autoxidation of oil and produce polymerized oil oxidation products (resinous matter). This cycle continues, as long as full-flow filters are used in hydraulic systems."

Heck, I wrote that....ah maybe not...:confused2:

Deano

OrangeRidge · Mar 15, 2011

Usta said:
.....Changed my hydro oil for the first time with just under 400 hours on the tractor.....

You left that waaaaay too long . This stuff is cheap and 200 hours
is quite enough for 11.5 litres that cooks at 80 centigrade within
30 mins of starting up.

bp fick · Mar 15, 2011

Are we to understand that you did not do the 50 hours service, as prescribed? Just curious.

I will go with the manual and only do the filters at 50 hours, as I don't wish to dump all that fluid. However, I have my doubts I'll leave it in for 400 hours. When I get to 200 hours, I'll make a decision at that point.

The new SUDT-2 being synthetic does influence my thinking here a bit, I admit.

abeal · Mar 15, 2011

bp fick said:
I will go with the manual and only do the filters at 50 hours, as I don't wish to dump all that fluid. However, I have my doubts I'll leave it in for 400 hours. When I get to 200 hours, I'll make a decision at that point.

The new SUDT-2 being synthetic does influence my thinking here a bit, I admit.

It's only 3 gallons, 20 minutes and $60. I was thinking I'd wait as well but with all the talk about people finding a bunch of shavings (I couldn't find any) and Kubota coming out with the new fluid, I just went ahead and changed it.

amg280 · Mar 15, 2011

BeezFun said:
"However, the majority of components of contaminants in working hydraulic systems are not solid particles like ACFTD but toluene soluble resinous matter, as shown in table 2. Resinous matter has polarity and is adsorbed onto metal surfaces. It is sticky and attracts other solid and fiber contaminents which then stick to them. By this mechanism, suction strainers will be clogged.

A suction strainer is actually a full flow filter. Hydraulic oil passes through a suction strainer at very high velocity. This means that both oil and the strainer will be electrified by friction of oil with the strainer. When oil passes through insulated strainers, static electricity will be accumulated on the strainers and the accumulated electric charge will be discharged by sparks. Spark discharge of static electricity will crack oil molecules and produce free radicals. Free radicals will propogate autoxidation of oil and produce polymerized oil oxidation products (resinous matter). This cycle continues, as long as full-flow filters are used in hydraulic systems."

Um...Duh??? Thats elementary my friend....:laughing:

No seriously was that in English?

TripleR · Mar 15, 2011

I go by the Operator Manuals on all my machinery and see no reason to waste oil etc. We have tractors made in the 50's and 60's still running problem free as well as motorcycles/ATV's made in the 70's that have had no repairs.

My brothers are mechanics and we have tried the more frequent changes as well as synthetics, but now pretty much go by the manuals. For racing or extreme conditions I would use different schedules/oils.