How to Tell if Front Axle Bearing is Bad?

[rScotty]

What you have described looks like an early warning of a seal and/or bearing failure. If just a seal, then using it won't hurt anything if the oil is topped off. If the bearing is involved then you are taking a gamble on more damage - but that is why you jack it up and wrestle with it.....to judge the bearing wear.

What kind of front axle oil are you using? If you are lucky and it is only the beginning of seal wear then changing away from trans/hydraulic fluid in the front axle toward 80w-90 gear oil will give you extra time of use - sometimes lots of time.. Just keep it topped off to protect the bearing. It isn't uncommon for seals to fail.

The problem with the advice I'm giving here is that half the time the seal is going bad because the Outer wheel bearing is already falling apart. Especially if doing a lot of heavy 4wd work.
In that case, the leak means "stop using it now". So be sure of what you feel when you jack it up and feel for play and roughness. If it were mine I'd jack it up and re-check the axle daily.
Luck,
rScotty

 

[ultrarunner]

In school my old Plymouth power steering pump was leaking at the seal… needed to add every month and no time to tear into it.

I tried power steering sealer and 20 years later never added a drop of fluid… it expanded the seal enough to stop the leak…

 

[Complete Turf Care]

I've changed front axle bearings on my Kubota L5740 four times and once on my L6060. The first time, the front wheel just locked up and would not roll. Of course there was lots of oil when this happened, but I had not noticed a leak before. Once, the whole wheel fell off. The other times, I noticed oil leaking and stopped using the tractor immediately and changed the seals and bearings.

Let us know what you decide to do.

 

[Suburban Plowboy]

This tractor was in 4WD for most of the last 150 hours because I didn't know any better. I use it for loader work.

I have ordered all the parts for a bearing and seal change, but they are stuck somewhere at the moment.

 

[grsthegreat]

Me, id park it until parts come in. I drove mine with minor leak. Than it failed spectacularly and cost me nearly $800 in parts it repair it. Loose metal parts hurt other gears.

 

[rScotty]

This tractor was in 4WD for most of the last 150 hours because I didn't know any better. I use it for loader work.

I have ordered all the parts for a bearing and seal change, but they are stuck somewhere at the moment.

Some things to think about.... Most of the compact tractors on the market since about 1980 use some variation of this same outer axle/bearing/seal design. And most of them - as well as the original company that invented them - recommend both/either trans/hydraulic (UDT) or multiweight gear oil. Both types of oil have similar viscosities.

This type front axle is NOT rated for full time use, and particularly not with a loader. It is intended just to get past a difficult spot and then put it back into 2WD.

Also, not all of these axle housings were vented. And of the ones that were, the venting was rarely taken up above the axle housing level via a tube. Without an open vent to the atmosphere there can be a pressure difference that will cause a seal to leak. It would be a good idea to check if yours is vented and improve the vent if necessary.

Not all of these front axles have a dip stick or even a level plug. If you have to guess, then the oil level should come up to between the middle to the top of the inside axle. That puts the level at the middle of the front differential - which is common for lots of splash-lubed front and rear ends.
Good luck,
rScotty

 

[Suburban Plowboy]

I don't have a dipstick, but I have a fill plug, a level plug, and a drain plug.

I will take a look and see if there is a vent. Thanks for the tip.

Kubota recommends UDT or Super UDT, and I assume that's what the original owner put in there. I topped it off with UDT.

 

[Fxfymn413]

Unfortunately front wheel bearing problems are common in the Kubota line, especially if you have been keeping the tractor in AWD all or most of the time. (Ask me how I know this)

I'd strongly recommend that you pull it apart to see what is going on before you cause more damage and expense.

 

[rScotty]

Unfortunately front wheel bearing problems are common in the Kubota line, especially if you have been keeping the tractor in AWD all or most of the time. (Ask me how I know this)

I'd strongly recommend that you pull it apart to see what is going on before you cause more damage and expense.

The problem is not just with Kubota, that axle is common to the part time 4wd compact tractor industry...and so are the associated seal and bearing problems.

There are a few AWD small tractors, but not many. Most are European made, a few are USA.

 

[Suburban Plowboy]

I don't blame Kubota for this. Not yet, anyway. I used the tractor on pavement with the front wheels engaged for a very long time.