B2400 hydraulic oil leak

dfred15

New member

Equipment
Kubota B2400
Oct 15, 2023
8
5
3
New York
Good morning. New to the forum and just picked up a B2400 yesterday with approximately 2000 hours on the clock. Tractor is overall in good shape for the age and looks like it was well taken care of and kept indoors.

Everything seems to function normally but I have a decent oil leak coming from the underside of the tractor under the driver's station. I am assuming from somewhere on the transmission but cant pinpoint exactly where. I attached some pictures showing this. Last night I cleaned the whole area with carb cleaner and wiped it down. It was already dripping again before bed and there was a puddle of oil underneath this morning.

I've poked around a but already on this subject and from what I've read so far on other threads I may be in for a large amount of work to correct it but wanted to get some input for anything I can check before diving into something that may be repaired without separation of the tractor. It's just hard to even see in there to confirm exactly where it is coming from. I may get a small camera that I can go up in through the drive shaft access and try to get a better view.

Any input is highly appreciated and I'm happy to take any additional pics which may help diagnose. I am planning on getting a manual fist thing this week.

Thank you.

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RCW

Well-known member
Lifetime Member

Equipment
BX2360, FEL, MMM, BX2750D snowblower. 1953 Minneapolis Moline ZAU
Apr 28, 2013
9,155
5,244
113
Chenango County, NY
Welcome to OTT!

It's hard for me to discern where the leak is. Can you get some other photos further out?

Better yet, can you find the area in parts diagrams from here? Snip and paste the area back here.

Looks like front end of the HST where propellor shaft comes in from engine?

Kubota Tractor Corporation - Illustrated Parts List (kubotausa.com)

Good thing is that the fluid looks very clean.
 

dfred15

New member

Equipment
Kubota B2400
Oct 15, 2023
8
5
3
New York
Welcome to OTT!

It's hard for me to discern where the leak is. Can you get some other photos further out?

Better yet, can you find the area in parts diagrams from here? Snip and paste the area back here.

Looks like front end of the HST where propellor shaft comes in from engine?

Kubota Tractor Corporation - Illustrated Parts List (kubotausa.com)

Good thing is that the fluid looks very clean.
RCW, thank you for the reply. Here are a couple more pictures further out and a screenshot from the manual showing the area its coming from. It is where the shafts meet the transmission just below the floor boards.
 

Attachments

Ktrim

Well-known member

Equipment
B2400, lA352 loader,3pth quick hitch/z122r zero turn/restored 52 farmall super a
Dec 23, 2020
425
337
63
Nazareth Pa
Take off the plastic cover under the seat and maybe the steel foot plate also so you look down onto the top of the trans. Sort of a birds eye view looking down may give you a better idea of where it's coming from.
There is a seal in front of the trans that will require splitting to change.
 

dfred15

New member

Equipment
Kubota B2400
Oct 15, 2023
8
5
3
New York
Take off the plastic cover under the seat and maybe the steel foot plate also so you look down onto the top of the trans. Sort of a birds eye view looking down may give you a better idea of where it's coming from.
There is a seal in front of the trans that will require splitting to change.
Thank you. I did take the plastic cover off and can see a bit better but still cant' tell. I will try taking a floor board off as well. The second to last picture in my original post is from the top side of the transmission under the cover. There looks to bee some oil weeping up there but does not look to be the large source of the leak to me.

When I pulled the rubber floor mat off, there was some oil on the metal floor board under the brake pedals and not sure where it came from. I've read on here about the power steering pump leaking and can make it look like there are leaks coming from elsewhere. Not sure this could be the case or not or if the leak is too far back towards the transmission to be a power steering leak.

Is it safe to put dye in the transmission oil reservoir or will this cause issues? I am going to do a deep clean/degreasing to clean off all oil. I was thinking of putting dye in to try and be certain of where the leak is coming from at least. Has anyone done this?
 

North Idaho Wolfman

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Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
30,209
6,382
113
Sandpoint, ID
Check all the bolts, these are notorious for a bolt being loose causing case leaks.
Another common possibility is that it could be an input shaft seal leak.
Yes you can put dye in the fluid, but that's really not doing to point to where the leak is, if you can't see it's origin.
 

Ktrim

Well-known member

Equipment
B2400, lA352 loader,3pth quick hitch/z122r zero turn/restored 52 farmall super a
Dec 23, 2020
425
337
63
Nazareth Pa
When my steering gear seal was leaking I got fluid under the front of the mat but not all the way to the back and it was a pretty big leak. Just fyi
 

dfred15

New member

Equipment
Kubota B2400
Oct 15, 2023
8
5
3
New York
Well, I did a thorough degreasing yesterday and then was able to watch under the tractor while it was running afterwards. The leak is much worse when the tractor is running and it looks to be coming from the seam where the pump housing meets the transmission and possibly other areas from above. Either way, looks like I will need to separate the transmission from the frame to repair. I will make sure to document my progress along the way once I start the project to show others as well as so I can ask questions if any come about. Thank you for the input so far.
 

dfred15

New member

Equipment
Kubota B2400
Oct 15, 2023
8
5
3
New York
Good morning. I wanted to post an update since it's been a while. I was able to get this torn apart last week which actually went pretty smoothly. From what insee so far, it looks like the leak is coming mainly from the prop shaft seal and at the seam where the oil pump housing meets the transmission behind the seal. It also looks to be leaking from the area around the trunnion lever control assembly based on the buid up and residual pil around that area. Based on the pictures attached, does anyone have any additional input on where to check for leaks?


Here is a write up describing the steps I took to separate for those who may be interested:

To separate, I started by removing the floor boards which included detaching brake linkages, brake locks, and rocker pedal linkage.

Next I disconnected the wiring for the tail lights and safety switches and fished it out from the rear section.

Next I drained hydraulic fluid and removed all lines connecting to the rear section. There is one line going up to the upper side of the rear under the seat with some sharp bends. For this one to come out freely when separating I also disconnected the linkage for the position control as it was interfering. For this i also removed the seat and toolbox to access this area.

Next I removed the roll pins on the drive shafts and made sure they were free.

Once I got to this point, it was time to separate so I used two lifting straps and went around the axels and crossed them under the mid PTO and connected them to a chain on my engine hoist. I placed a jackstand under each side of the loader frame to support the front section. This is where I then removed all bolts and nuts holding the two sections together. I kept the top two nuts on loose until it was free to make sure it was supported properly. Once I had it free, I removed them and the rear section slid right out very easily. Once the shafts were clear of the frame, I rotated it where it sits now and it's supported by the link arms.


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dfred15

New member

Equipment
Kubota B2400
Oct 15, 2023
8
5
3
New York
Looking to order all the parts I need to replace and having trouble confirming the part number for the shaft seal on the front drive output shaft. The diagram shows a seal close to the location but looks to be in the incorrect orientation so not sure if that is the correct seal. Can anyone confirm if the seal called out as 270 on the attachment picture is correct for this? Looks to be part number 66101-36720. Thanks.
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BeninCT

New member

Equipment
Kubota B2400 HST
Dec 25, 2023
21
16
3
CT, USA
Did you get this wrapped up? I just purchased one of these tractors and I don’t have a leak like this but I suspect someday I may. Always interesting to watch.
 

Dustball

Active member

Equipment
2016 B2650HSDC
Sep 15, 2023
294
172
43
Hudson, WI
Saw your post on FB. #550 would be the shaft seal that goes in #530, the cover shown in your picture where the shaft seal is leaking. #270 is the seal for the trunnion arm, #290.
 

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Last edited:

Dustball

Active member

Equipment
2016 B2650HSDC
Sep 15, 2023
294
172
43
Hudson, WI
Last edited:

North Idaho Wolfman

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Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
30,209
6,382
113
Sandpoint, ID

Dustball

Active member

Equipment
2016 B2650HSDC
Sep 15, 2023
294
172
43
Hudson, WI
You realize this is a 2 month old post and he's more than likely gotten it done.
On his FB post, he just ordered the seal today.

I'd rather have the info documented here for others to find because any info posted to FaceBook is lost in a matter of days.
 
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