Oil & Fuel HST oil level

[namesray]

Think of it this way. Place a small dixie cup upside down into a sink full of water. The airgets trapped in the cup and the water wont let air out. You can push the cup all the way into the water and the air pocket stays in cup. Now poke a hole in the bottom of cup that is at top of water level. The air can get out and the water will rush in cup to rest of water level out side the cup.

Now think of the cup as the dip stick tube. Think of the sink full of water as the hydraulic reservoir. Plenty of ventilation as no cover over sink to seal it in. When you poked a hole in the cup, you allowed a path for the air to get out of the cup. When you remove the dipstick, you give the air a path to get out. Then the fluid level can be checked when you re dip.

There is likely no vent problem what so ever with your tractor.

The reason I think some equipment will do it and others don't, is due to how well the seal is on the dip stick. I am sure there also might be other reasons as well.

The reason the fluid level goes below the dip stick can be due to either hill operation or usinghydraulic functions that take fluid from resivior and to implement, example, loader.

 

[don white]

Kanook
Thanks it is nice to know I am not wacko. I still think there should be a crank case vent somewhere.

 

[don white]

Namesray
Yea I get what you are saying and it makes sense. The case gets pressurized and compresses the oil so the level appears lower until you pull the stick. Again it seems like there should be a case vent.

 

[SpeckuldTrout]

Namesray
The case gets pressurized and compresses the oil so the level appears lower until you pull the stick. Again it seems like there should be a case vent.

The oil is essentially in-compressible. Using a compressible fluid would defeat the main benefit of a hydraulic system.

I think what Namesray suggested (makes sense to me) is that the dipstick tube is a pocket that air can get trapped in when the tractor is tilted during operation, or the fluid level goes down slightly and back up during use of an implement. The only way that bubble can get out is when you pull the dipstick or it leaks around the rubber seal on the dipstick (which if there were much pressure involved I expect it would). A vent elsewhere in the case would not change this.

 

[namesray]

Remember, the sink full of water in my example is fully vented, and the air pocket still gets traped in the cup. The vent doesn't matter in this issue. It is the seal rings on your dip stick that is most likely causing thatlittle air pocket getting trapped in your dip stick tube. They seal so well that it traps air just in the tube, not the whole rear case. Its normal. Some dipsticks seal better then others.

Your trans/hydraulic system on your tractor does have a vent. On my kubota b tractors itwas on the right side, on top of the rear case, just under the seat. It looked like a rubber, black, candy cane top, you know with the little curl at the top. That was the vent, atleast on mine. Yours may be different, but should be located near the same location, either left or right under the seat comming out top of rear case of tractor.

 

[Barneyhunts]

I see the same thing when I check the fluid on my B7800. Hasn't been a problem.

 

[SwampCat]

So as with my ice cream cone, the best thing to do is DOUBLE DIP .

 

[Kanook]

namesray.....can't argue with that logic...makes perfect sense to me...thanks

 

[don white]

Alright your explanations are sinking in now. Agreed oil is not compressible and I get the idea of the tube.
I just went out and check there is a tube in fact the tube is not even in the gear case. There is an exposed steel tube (for the dip stick) that connects with a rubber tube (hose) on the outside of the case. The rubber tube (hose) is hard to see. Yes if the oil drained out during operation on un-level ground it would not fill the dip stick tube if the dipstick seals correctly. The dip stick has an o-ring and it will seal. I thought the dip stick went directly into the gear case which is why I wondered where the oil went.

Sometimes the simple stuff is not so simple.
Thanks guys you have relived a worry.

 

[S8r9d]

i didn't get any owners manual with my tractor and only had it a couple days I just haven't tracked one down yet but what position do you have ur cylinders in for the check. B21 TLB. Sorry not trying to hijack. Thx