BX1850 hydraulic fluid leak

[Tominana]

I have a BX1850 that I've operated for about 10 years now. it's always had a very slow hydraulic fluid leak, but nothing major. I would top it off every 50 hours engine time or so. The leak seemed to be on the front of the HST, somewhat let of center (left from point of view of operator sitting in the seat). Last week, after mowing, I noticed a dramatic leak, about the rate of what would come out if you tipped a beer bottle on its side. Same location, I think. I removed the ROPS, seat, fender, floor to get a better look. No obvious ruptured hoses or fittings.

I suspect the seal where the drive shaft comes in from the engine, thinking that the HST fan would spread any leak all around. And, I found the wire for a marking flag wrapped around the shaft, right where it goes into the HST. But I'm confused. My shop manual says that there should be an internal circlip and an oil seal there, but the parts diagrams I can find (and at my local dealer) don't have any such thing. The guy at the parts counter thinks that the bearing on that shaft, being sealed, may make an oil seal unnecessarry. I don't see a groove for an internal circlip, either.

Does anyone know if an oil seal goes in there? Looks like there are press-in ones for the rear PTO and for the rear axles, but should there be one here, too? I'll attach a photo of the shaft where it enters the HST

 

[Bee-Positive]

Here's a parts shot off Kubotabooks.com from a later model BX1830d which is the same hp as yours with several rings and a clip. Maybe the bearing is working it's way out so you can't see the slot for the clip ring?

 

[Bee-Positive]

Not sure I got the right picture there in the previous post but looking at my BX1880 WSM it's similar to yours although much newer and it does have an oil seal and a circlip.

 

[North Idaho Wolfman]

The oil seal is behind the bearing.

 

[North Idaho Wolfman]

Here's a parts shot off Kubotabooks.com from a later model BX1830d which is the same hp as yours with several rings and a clip. Maybe the bearing is working it's way out so you can't see the slot for the clip ring?

NOT anywhere even close to a BX1860 or BX1880
100% bad info

 

[North Idaho Wolfman]

Not sure I got the right picture there in the previous post but looking at my BX1880 WSM it's similar to yours although much newer and it does have an oil seal and a circlip.

You do not have a circlip

 

[Tominana]

The oil seal is behind the bearing.

View attachment 169892
View attachment 169893

Thanks, North Idaho Wolfman, I'm aware that there is an oil seal to the inside of the port block cover. However, it seems to me that since there is fluid circultng in the oil cooler cover, that fluid also requires a seal to keep it leaking out at the drive shaft. I think I will have to take it apart and have a look

 

[Tominana]

Not sure I got the right picture there in the previous post but looking at my BX1880 WSM it's similar to yours although much newer and it does have an oil seal and a circlip.

Thanks, Bee-Positive. Even though my Kuboto WSM specifically lists that is is for the BX1850, i wonder if it is somehow mixed up. I can't see a groove for an internal circlip on my BX1850

 

[North Idaho Wolfman]

Thanks, North Idaho Wolfman, I'm aware that there is an oil seal to the inside of the port block cover. However, it seems to me that since there is fluid circultng in the oil cooler cover, that fluid also requires a seal to keep it leaking out at the drive shaft. I think I will have to take it apart and have a look

There is a gasket on the oil cooler cover that keeps the oil in the cover.
#10 second picture

 

[Tominana]

There is a gasket on the oil cooler cover that keeps the oil in the cover.
#10 second picture

Yes, that makes sense now, thank you. I'll replace oil seal and gasket.

 

[North Idaho Wolfman]

Yes, that makes sense now, thank you. I'll replace oil seal and gasket.
View attachment 169910

I would suggest replacing the bearing and O-rings also while you have it open.
And FYI: You'll be dealing with 2 gaskets and 2 O-rings

 

[Tominana]

I would suggest replacing the bearing and O-rings also while you have it open.
And FYI: You'll be dealing with 2 gaskets and 2 O-rings

Thanks, I will also replace bearing and O-rings.

 

[Joe.G]

I watched this video last night, I believe it is the same but I may be wrong.

 

[Tominana]

I watched this video last night, I believe it is the same but I may be wrong.

Great video, thank you. I think my problem is the same as his. Instead to taking the transmission out, I removed the two round bars closest to the oil cooler. Worked for me, and I think easier. Everything is apart now, and I'm waiting for parts, hopefully middle of next week.