Kubota b7200 Black hydraulic fluid/ bubbling out of dipstick

[Beastman14]

Hey everyone. I have a kubota b7200 tractor with standard transmission. I just bought this tractor and know very little about it. The transmission/hydraulic fluid is very dark and looked to have metal flakes in it. It is also bubbling of of the dipstick and pushing through the boot covering the base of the shifter. I assume I have a pump that is bad causing the metal flake and dark fluid but don't know which pump it is or where it is located. Also what would cause the bubbling out of the dipstick? Is it not venting? Any help would be greatly appreciated.

 

[pmsmechanic]

Usually when fluid in a reservoir is bubbling it means that the suction line has a leak in it. Leave it sit several hours and check the hydraulic fluid levels. Is it overfull? Gears churning up oil will also add air to the hydraulic fluid. Are what you see as metal flakes just air bubbles?

The pump/pumps are usually driven off of the front gear case on the engine. I'm not familiar with your model so won't comment on that. I wouldn't worry too much about the dark color of the oil. I'd be more worried about the metal flakes.

When the oil is warm remove the drain bung on the bottom of the gear case and drain out about a quart of oil into a clean container. Let that sit for a day and then slowly pour off the top oil till you have about an inch of oil left. If there are lots of metal flakes you should be able to see them in the oil that's left. Alternately let the oil settle and swish a clean magnet around the bottom. It'll pick up the steel fillings but not the brass ones.

 

[Beastman14]

Definitely metal flakes. The color is like used motor oil. Its can't be normal. I will double check everything though. If it is metal flakes is it just the pump? Is there a pump inside the transmission as well as one on the side of the engine?

 

[CalG]

"Black" fluid from the transmission signals a leak from the engine into the transmission. Not an easy thing to do, as there is a clutch in the way.

But

I suggest an engine oil change.
And a Transmission fluid dump and refill. Change the transmission fluid if it doesn't look like "new" fluid.

THEN

Watch the fluid levels all around.

This tractor is new to you because someone else got rid of it.
You must wonder WHY! Find out!

 

[pmsmechanic]

The engine oil could also be leaking in from the hydraulic pump.

 

[Beastman14]

So oil could be getting into hydraulic fluid...sounds great. If its not coming in from pump would the only other option be from the rear main seal in front if the clutch? If so could this also be the reason I getting hydraulic fluid pushing out of the dip stick? Preassure from the crankcase?

 

[BeezFun]

So oil could be getting into hydraulic fluid...sounds great. If its not coming in from pump would the only other option be from the rear main seal in front if the clutch? If so could this also be the reason I getting hydraulic fluid pushing out of the dip stick? Preassure from the crankcase?

If the level of engine oil is not decreasing, then it's not coming from the engine. It could be that the person who sold it overfilled the transmission. It's also possible water got into the system, either by being driven through water deep enough to come in the breather (wherever it is on that tractor), or the filler cap was left off and rain was getting in, or who knows. I think it's hard to know what's going on without doing a reset and draining engine and transmission, filling them, and then monitoring very closely to see what happens. You can also send the oil for analysis and find out what the metal is, that will tell you something about where it's coming from. That only costs about $30 so it might be worth it to get you on the right track.

 

[pmsmechanic]

Beastman14 you have no history on this tractor. You haven't told us if the transmission is overfilled. The question "Pressure from the crankcase?" tells me you know little about mechanical things.

For us to be able to help you diagnose your tractor you need to go through things in an orderly manner. To me it feels like you are wildly guessing at things that you have no idea about.

The suggestion has been made to drain the oils and start over from scratch so as to be able to observe and make conclusions. You need to do that. Also as suggested I would take a sample of the transmission oil mid drain to send away to be analyzed. Buy the oil analysis kit first before you drain the oil. Follow their instructions for an accurate sample.

Read my first post. I gave you the most reasonable scenarios as to why the transmission oil is bubbling out. If pressure form the crankcase is moving oil from the engine to the transmission then the engine should be out of oil. This is highly unlikely. Check and do the simple stuff first.

 

[Dave M7040]

You are in luck in that there are free operators and WSM's for your B7200 available on kubotabooks.com

Index of Kubotabooks/Tractor Owners Manuals/

I have not looked but suspect there is a suction filter to keep pieces of gear teeth and other brake material from getting into the hydraulic system itself.

One owner who tried repeated cleaning this filter found a big improvement with a new filter. I think the filter was like a pad with fine screen layers stacked on top of each other.

If you let the tractor sit and then as you start to drain the transmission, catch the first quart of so of fluid which comes out.

Water being heavier than oil will be in the bottom where the drain plug(s) are. Water is bad news for everything so you need to find a way to keep it out.

Dave M7040

 

[rScotty]

Sounds like a bad seal to the hydraulic pump is letting the engine oil and hydraulic fluid mix. Hydraulic/transmission oil is not ever blaci. First step is get the manual and change out all the oils and filters. Put the right ones on and right quantities. Some tractors of that era also had a cleanable screen filter for the hydraulic/transmission filter. Take a look for one of those.
The replacement oil needn't be best quality oil. You are using it to see what happens & will probably change it again. The hydraulic system holds a lot more oil than the engine, so I expect that pressure from the hydraulic pump is forcing oil past the seal and into the engine. That would explain the dipstick bubbling too, because you would eventually see a very slight reduction in transmission oil level, but a large increase in engine oil level. If so, the next step is to replace the shaft seal in the hydraulic pump - or replace the pump complete with seal. That's a medium level mechanical knowledge project. Easy enough for anyone with experience. Too bad it wasn't caught quicker, but this should be fixable without major problems.
Good luck,
rScotty