DK40 front bearing failure @ 1300 hours

[dfkrug]

Be forewarned, the following has not been tested in this specific application in any way. Just "thinking out loud"

After reading through SKF's bearing book, I would say that their NUP208ECP and NUP209ECP roller bearings could possibly be a suitable replacement for the 6208 and 6209 ball bearings.

This is exactly the failure and the solution to failed fork bearings in my old Kawasaki street bike. The ball bearings failed, and roller bearings that had the same dimensions solved the problem. It was so common, the maker eventually went roller. Duh.

 

[Kioti Paul]

xcgreene, the roller bearings sounds like an excellent idea!

I plan to inspect my bearings, probably in early march. They are not giving any trouble - as far as I know- but this thread has me concerned as to what MIGHT be happening. I would really hate to break down in the middle of hay baling.

If I decide the bearings need replacing, I will go with the roller bearings (I ain't skeered!)

 

[southerniltractor]

Howdy folks,

I've been planning on installing new front wheel bearings at 1000 hours. Upon reflection, it may be prudent to do this sooner than later. I'm due to change the axle lube and it makes sense to do this at same time.

Looking at the service manual, I pull off the wheel, unbolt the hub and have full access to both bearings and the floating seal. There is a large o-ring that seals the hub. Do I have this right?

As far as parts, I'll need the bearings and a new seal?

Appreciate your thoughts guys.

Be well,
Mike

 

[xcgreene]

Howdy folks,

I've been planning on installing new front wheel bearings at 1000 hours. Upon reflection, it may be prudent to do this sooner than later. I'm due to change the axle lube and it makes sense to do this at same time.

Looking at the service manual, I pull off the wheel, unbolt the hub and have full access to both bearings and the floating seal. There is a large o-ring that seals the hub. Do I have this right?

As far as parts, I'll need the bearings and a new seal?

Appreciate your thoughts guys.

Be well,
Mike

All seals should be replaced when doing this job. Especially the floating seal. Curious of their price. I've seen similar tractors seals go for $50 each. But for 1000hrs, and piece of mind, its well worth it. I still see no reason those bearings wouldn't work, but if you had time, removed the bearings first, and take measure, and double check the roller bearing replacement part numbers. again, what i posted there in the past, was just a catalog flipping exercise, and something I'll confirm myself when I start having front axle issues.

 

[RickB]

I think plain roller bearings are a poor choice for this application and so do all those folks that design and engineer tractors. Ball bearings and opposing tapered roller bearings are designed to carry axial loads while plain roller bearings are not. CUT front axles are subjected to substantial axial loading. There are reasons that tractors do not use roller bearings to support axles, front or rear. Individual engineers can have stupid ideas put in production, an entire industry rarely does.

 

[dfkrug]

Yeah, we should not conflate straight roller bearings with tapered roller bearings. "Roller bearings" could mean either.

My example above was for tapered RBs.

Here is an example of a straight or plain RB, in an MFWD Dana-Spicer axle from a Deere CUT. First time I ran into a bearing made by Link-Belt.

 

[grsthegreat]

I wish i saw this post earlier. I lost an outer bearing that took out my cover and axle hub. Ill be out about $1000 by the time this is over. Im going to replace bearings and seals on other side also to be safe.

and ill tell you what……gettin* cover and axle were next to impossible. Says its all covid related. More than likely there sitting in a container in LA docks somewheres.

 

[5030]

More than likely there sitting in a container in LA docks somewheres.

Or floating around on a container ship 'loitering' in the bay...

 

[5030]

I think plain roller bearings are a poor choice for this application and so do all those folks that design and engineer tractors. Ball bearings and opposing tapered roller bearings are designed to carry axial loads while plain roller bearings are not. CUT front axles are subjected to substantial axial loading. There are reasons that tractors do not use roller bearings to support axles, front or rear. Individual engineers can have stupid ideas put in production, an entire industry rarely does.

Don't know if I agree with you actually. I've never seen any car, light truck or heavy duty truck with ball bearings in the hubs. All tapered rollers. I think ball bearings in tractor axles are a cop out for cost to manufacture and larger tractors in the ag class all have tapered rollers in the hubs.

 

[grsthegreat]

Well, new bearings, seals and outer case showed up today. Waiting for axle hub.

 

[5030]

Well, new bearings, seals and outer case showed up today. Waiting for axle hub.

Any word on lead time?

 

[grsthegreat]

Not a clue…. No tracking info. Luckily not middle of winter snow

 

[JimR]

This is exactly the failure and the solution to failed fork bearings in my old Kawasaki street bike. The ball bearings failed, and roller bearings that had the same dimensions solved the problem. It was so common, the maker eventually went roller. Duh.

This brings back memories of the last 56 Chevy I owned. It had ball bearings on the front hubs. When they wore out for the second time I replaced them with a set of front hubs off a 63 Impala with tapered roller bearings. That ended my bearing problems.

 

[grsthegreat]

Looking thru the service manual, they use different kinds of bearings throughout the tractor. I dont think they use a certain kind of bearing to save some money. They use taper bearings in other parts of front axle assembly.

the floating seals have me a bit stumped. They dont seem to fit completely in cover. I cant find any info on their installation, and the manual doesnt detail their installation process. I did take the good axle apart, and i see they dont seat fully there either. So i take this to mean there not supposed to fully seat. i will call my service dealer to confirm this.

 

[southerniltractor]

I look forward to hear how your repair goes. I've got a bit less than 700 hours on my DK40se hst and intend to replace bearings at 1000 hours a preventative maintenance.

Oh, I just saw your Aug 16 post GRS. Like you, I didn't find much info on how the seals are installed in my service manual. What did your dealer have to say?

 

[grsthegreat]

They told me to coat them with rubbing alcohol and simply push them into place. I did that on both sides and install went easy. Been up and running for little over a week.

 

[5030]

the floating seals have me a bit stumped.

On my Kubota's the floating radial seal is set using an appropriate sized seal driver on in my case. a large 1" drive socket. Don't seat all that far either as the upper knuckle has to apply sealing pressure to it.

 

[grsthegreat]

On the kioti they dont seal completely, they sit slightly raised on both the cover and the axle. I had to physically push both sides together till they bottom out inorder to get the split ring to lock inplace. This is how the manual and the service dealer told me to do it. Once split ring is installed and pressure is released, the 2 parts separate slightly, allowing for movement. The O ring allows for movement of the seal. I guess this technology is over 100 years old according to what i read on the matter. You wouldnt think it would make for a good seal, but no leaks.

 

[5030]

All that is important. Of course the radial seal never has continuous oil against it anyway and on my Kubota's the top zerk on each outboard keeps the radial seal filled with grease.

 

[repete]

This used to be a common failure in the front end of my L2550DT. When the wheels are reversed to gain additional width of the front end the entire front end load is placed on the outer bearing as opposed to being distributed between both bearings.
I know a lot will respond with a disagreement but I can only share my experiences as I turn 6300 hours on my 2550.