DK40 front bearing failure @ 1300 hours

[MotorSeven]

I just wanted to post this up since some of us here might have to deal with this in some point in time. Back in late summer the RF hub bearing failed, I noticed some oil leaking out(I had no load on the FEL), drove it over to my shop, took it apart and replaced the bearings at a cost of under $100 in parts.

A few weeks ago the LF went, but the circumstances were quite different. I had over 2,000llbs of Poplar logs on the FEL and was running down the paved road at about 8-10 mph. I heard a "screech" from somewhere in the front axle, then a loud "pop" like a .22 rifle going off. Immediatly, a large quanity of gear oil came pouring out of the knuckle bearing area. Since I was blocking the 2 lane with 11' logs, I decided to limp the tractor 200' to a place I could pulll off. This decision most likely added to the damage to the ring and pinion gear set. Anyway, I dumped the logs, walked back and hooked up the truck/trailer, then drove back and loaded the tractor for the 1/3 mile ride back to my shop.

When I got it loaded and lifted the front end using the FEL, the wheel & tire fell off:

A closer look:

 

[MotorSeven]

The outer ball bearing cage exploded, sending scrap metal throughout the hub and gears. The hub case itself and the large gears were also damaged. I might have been able to re-use the pinion and Ring gears, but I chose to replace them, along with all the large lower bearing sets, the hub, and the upper bearing. The procedure is pretty straightforward and no special tools are needed except for a large set of ring pliers which of course I did not have. So, I ground down the ends of a large pair of needle nose pliers. The price tag on the parts was about $1100. IF I had immediately stopped and not moved the tractor after I heard the "screech", it is probable that the damage would have been much less significant.

This occurred at a little over 1300 hrs. As some here may know I have extensively used this tractor to carry maximum capacity loads on the FEL to build my house, so I would guess that I have about 400 hours on it in 4WD and carrying a load. The fact that the bearings failed really do not surprise me, and looking back, I should have replaced the LF bearings after the RF went back in the summer. Other than the bearing failure, the only other issue in these hours has been a head gasket that was covered under warranty, so I have no complaints about my DK40 at all.

 

[GMIslander]

What are you using for lube in the front end? gear oil 80/90 or HST oil.

 

[rd_macgregor]

The subject line caught my attention since my DK45 is now at 1216 hrs. I don't have the shop, tools or competence to fix something like this, so I'm hoping not to suffer the same sort of failure on my machine anytime soon.

 

[MotorSeven]

GM- 80/90

Mac- There is really not much to it. The bearings are not even tapped or pressed in and the two large ones have the race attached. In other words, you can reach in and pull out the whole bearing by hand, then slid in the new one. The second to last pic has the new upper bearing in place...it just slides in(that was the one that "grenaded"). Also, unless you have carried max loads like I have for hundreds of hours(most up/down a steep 1/3 mile long driveway) I doubt yours will ever fail. I have been hard on this tractor & heavy wear and tear does take a toll.

 

[Billrog]

On my last tractor I replaced the front wheel seals and bearings 3 time over a period of 20 years and 4500 hrs. Fortunately I always caught the failure as soon as the was a seal leak and before any major damage was done. I could blame the tractor as I used the loader to the limit often carrying large logs.

 

[DieselBound]

MotorSeven, sorry to hear of this event. I know what it's like to have one repair and then soon afterwords have something else (which may or may not be related) popping up. And thank you for the detailed info, which I'll be sure to commit to my knowledge base.

I'm wondering... Would it be prudent to do periodic inspections of the bearings?

Seems that the seal leak stems from a bearing starting to get out of shape (stressed), would that be the case? If so, then, yes, watch for leaks and figure on needing to replace the bearing, right away.

 

[southerniltractor]

Howdy MotorSeven! It has been a while since your last post and I hope outside this event life is treating you well. Always enjoyed your tractor stories as you built your home.

Most of my work with my DK-40 is with the FEL moving large boxes of firewood and anything heavy my carpenter buddy can't handle. Based on your experience, I may slide new bearings on at about 1000 hours.

Mike

 

[jeff9366]

I have extensively used this tractor to carry maximum capacity loads on the FEL to build my house, so I would guess that I have about 400 hours on it in 4WD and carrying a load.

How about describing your TIRE FILLS, air/liquid, and typical Three Point Hitch COUNTERBALANCE while moving maximum capacity loads on the FEL ~~~~~

 

[RickB]

This is what happens when manufacturers overspec FEL's relative to front axle capacity. Putting a ton on the forks and driving at high speeds will do exactly this.

More proof that just because you CAN do something doesn't mean you SHOULD.