What are the dangers from over filled hydraulic fluid?

[Tornado]

Ill give a quick backstory that makes me curious about this question. If you arent interested in the why, then skip to the next paragraph. I recently did my 50 hour maintenance on my L2501. As part of that I had an issue with the hydraulic filter that was discovered only as I took the filter off, and it prevented me from putting the new filter on quickly, so I lost several gallons of hydraulic fluid, forcing me to essentially replace most of the hydraulic fluid at 50 hours. I detailed this adventure in another thread recently and what caused it all. Fixed it all and refilled. I've since learned that the little sight glass used to read the hydraulic fluid level is really sensitive, in that if the tractor isnt perfectly level it can read low or high, and also once the fluid level enters the window, it can quickly go from bottom to the top of the window with seemingly just a few ounces of added fluid. So When I did the maintenance I followed the proper procedure, fill it up to around mid of window, then run the tractor afew minutes, turn it off, recheck the level. A few days after all this however the level looked low - no oil was showing in the window. Drove it up to my garage where I could park it on a concrete pad that is pretty level, and it was showing at the bottom ofthe window. I added just a little extra fluid, and also added a little extra to front axle to bring them both back to proper level. Now tis past weekend after parking the tractor from a day of work on it I look down and now the window is totally full of fluid - looking too full. Does the level go up and down on temperature? Perhaps it expands when hot and looks more full? I can maybe just barely see an air bubble at the very tip top of the window, if thats what Im seeing.

Given this, I became curious - what would be the danger of having the hydraulic fluid level just slightly over filled? What is the most optimal location in the sight glass to shoot for on the hydraulic fluid? Right in the middle? upper end? lower end? Doesn't matter? Based on my experience from the maintenance, it seems bottom to top of glass is just a few ounces difference in overall volume. I thought about just sticking a little hose with a syringe down into the oil reservoir and just 'sucking up" a little oil to bring it down into the window again. Havent tried this yet though. If it is over filled, it is only just barely so. Im finding that this hydraulic fluid level is really finicky to get it perfect. It seems its different everytime I check it. And yes I am always check it with all hydraulics withdrawn/down, and engine turned off. Given the level in the window seems to go up and down with such little volume differences it seems just a little here or there in a cylinder makes big changes in the sight glass.

While we are at it, what is the danger of engine oil in a tractor also? After my 50 hour maintenance, I am sitting just a very tiny smidgen under the "full" mark on the dipstick. Should I be more toward the middle of the engine oil dipstick? I Have read that with engine oil you never want to over fill it. Perhaps someone can expand on this topic a little.

 

[SidecarFlip]

In as much as all fills are approximate, it won't matter. However, gross overfilling an engine can cause the crank to whip the oil up and / or place undue stress on oil seals. Same with the transmission. Oil seals aren't meant to be submerged totally.

 

[Nicfin36]

I've experienced the exact same thing with my L2501 lately. I ran it for the first time this year, just because the unrelenting rain has kept things too wet here. Last year, I lost a good amount of fluid because the hydraulic fitting for the backhoe spun loose.

So, the dealer gave me a bucket of fluid and I topped it off. The other day, I ran it for about an hour. I parked it at a somewhat level spot. Later, I came back and decided to look at the window. The window was completely full. I was thinking I had overfilled it. But, I left it alone and came back later. I could see some airspace in the window then. I have since checked it once again, only to see the fluid near the bottom of the window.

So, yes, it appears to be very sensitive. I'm sure hot fluid and cold fluid may be factors, among others.

 

[Tornado]

I've experienced the exact same thing with my L2501 lately. I ran it for the first time this year, just because the unrelenting rain has kept things too wet here. Last year, I lost a good amount of fluid because the hydraulic fitting for the backhoe spun loose.

So, the dealer gave me a bucket of fluid and I topped it off. The other day, I ran it for about an hour. I parked it at a somewhat level spot. Later, I came back and decided to look at the window. The window was completely full. I was thinking I had overfilled it. But, I left it alone and came back later. I could see some airspace in the window then. I have since checked it once again, only to see the fluid near the bottom of the window.

So, yes, it appears to be very sensitive. I'm sure hot fluid and cold fluid may be factors, among others.

Yea, even when the tractor appears to be sitting pretty level it can appear totally empty or over filled. Move to concrete pad and now it shows more normal. Its literally just a few ounces. That window must be in a fairly narrow part near the top.


Appreciate the info sidecar. I think ill not mess with it then.

 

[Bulldog]

Temperature will affect the fluid level. Always check it cold to get the most accurate reading. Middle of the glass sitting on level ground.