Hydraulic oil & filter change after first year or not?

[slomo]

Got to get all the metal and junk out of the system early. Just like a new engine. It will be full of glitter like metallic flakes.

slomo

 

[Born2Mow]

Got to get all the metal and junk out of the system early. Just like a new engine. It will be full of glitter like metallic flakes.

Typically, you have a filter to remove the small debris from the hydraulic fluid. The problem is simpler than that.

You change your fluids on a calendar basis due to WATER. These large cases experience internal condensation with the changes of seasons. This might not be an issue for the pro, but rarely does a home owner run his equipment long enough to "cook off" the water vapor. The filter certainly doesn't remove water. So the only way to rid the system of water is to change the fluid.

Very rarely are we talking about liquid water. Most of the time this water is absorbed by and suspended in the hydraulic oil. But it reduces the effectiveness of the fluid and allows rust to form on ferrous surfaces. Rust then leads to advanced wear.

In the case of someone buying a 5yo mower with only 20 hours on it, the hour meter is telling you the mower hasn't been hot in a long time... therefore (although the lubricant may not be "worn out") those low hours may be proof that a fluid change is required due to possible water absorption.

So it cuts 2 ways... Change fluids based on high hours (lots of use), but also change fluids based on low hours within a calendar period (possible water inclusion simply due to non-use).

[Engine oils have the same issue with water absorption, but since engines operate at a much, much higher temperature, even a 30 minute residential mowing session is enough to keep water inside the engine cases at much lower levels.]

Hope this helps.