B7800 - Busted Axle at 441 hours

[slan]

And we still keep doing things like this.

http://www.tractorbynet.com/forums/kubota-owning-operating/151093-rock-digging.html
No offense Texas, just happened to be the most recent "Look what I did with my tractor" post

Hopefully we can all be reminded these are not a commercial use unit that are designed to handle anything it can lift and then navigate everything from deep mud, rough terrain, or anything else a construction worker can throw at it on a Saturday close to quitting time.
Thats why they cost $40,000+

Not saying this is the case here but just makes you shake your head when you see things being done that are way beyond what it was designed to handle.

IMHO

 

[JOHNTHOMAS]

And we still keep doing things like this.

http://www.tractorbynet.com/forums/kubota-owning-operating/151093-rock-digging.html
No offense Texas, just happened to be the most recent "Look what I did with my tractor" post

Hopefully we can all be reminded these are not a commercial use unit that are designed to handle anything it can lift and then navigate everything from deep mud, rough terrain, or anything else a construction worker can throw at it on a Saturday close to quitting time.
Thats why they cost $40,000+

Not saying this is the case here but just makes you shake your head when you see things being done that are way beyond what it was designed to handle.

IMHO

Easy for you to say:GL3240 HST, 724 FEL, Loaded R4s, Squealer 160 Bush Hog, 72" Box Blade, and more to come.
Ford 655 TLB
Cat D6B Dozer
The rest of us don't have a yard full of heavy duty construction equipment to call in when our job stretches our little tractors. You've never pushed your 655 to past it's limit? OK get rid of the D6 then tell me you've never stretched your 655 past it's limit. We all, well most of us that do more than mow "test" our limits and that's why I keep trading and why I "enjoy" using my Kubotas. You know what I'm talking about!!

 

[slowzuki]

Kubota was pretty fair to you I'd say. My buddy didn't make out nearly as well with Deere when his front axle came apart, or when his rears came apart. He uses it hard though.

They have to have a warrantee period that expires or the tractors would cost even more.

 

[ccogg]

The front wheel on my b7800 fell off at about 330hrs/4yr. Same type of crack as yours with about 80% of the cracked circumference oxidized. I don't have a cab and mine was cheaper to fix, but no warranty parts for me. If they had offered parts I would have felt neutral about the whole experience, parts and labor would have been impressive and I would now be a "loyal" customer. Either way I consider the failure a "manufaturer defect" rather than "opperator error". All told I feel like the tractor/company is OK, but not great.

In terms of rear counterweights, in practice I can and do lift/carry significantly more wheight in the loader when I have my counterweights (~500lbs) on the 3-point hitch. Given the relative lever arm of the loader and 3PH I have to believe that the front axle experiences a much greater load when I have the counterweights on than when I do not. The distance from the rear axle to the counter weight is about 1/3 of the wheelbase. Therefore the counterbalance takes about 160lbs off the front axle. On the other hand, any weight in the FEL results in 1.5X loading on the front axle and wieght on bucket forks is probably about doubled. The tractor is vastly more stable and has much better traction with a counterbalance, but in practice it probably increases front axle loading.

 

[brain55]

I'll share a little secret with you guys. If you ever run filled front tires on this era machine this includes the B2710, B2910, etc. You have to throw away the original stub axles and upgrade to the B21 stub axles. It is the only way to stop breaking them. Trust me I have done this upgrade at least a dozen times. The B21 axles do not break. You will also have to buy new studs because the B21's have screw-in instead of press-ins. Don't run to your dealer expecting them to do this under warranty, it won't happen. If your axle fails under warranty you might get them to let you pay the difference in cost. I imagine very few even know that this is possible.

Brian

 

[art]

Why would anyone with a loader run front loaded tires? Maybe we should get the right equipment for the job!

 

[brain55]

Why would anyone with a loader run front loaded tires? Maybe we should get the right equipment for the job!

It is done everyday. If you have a tractor on a construction site, and you don't foam fill the front tires you will spend most of your day fixing flats. The fronts pick up 90% of the nails.

Brian

 

[rjkobbeman]

As has been said:

Loading the rear tires, or adding wheel weights, helps keep the rear on the ground... but does not take weight off of the front axle.

Adding weight behind the rear axle (implement or ballast box on 3ph) helps keep the rear on the ground AND takes weight off of the front axle.

What has not been said (that I recall):

If there is not enought ballast in the rear and the rear end starts to come up, the entire weight of the tractor AND ALL OF THE WHEEL/BALLAST WEIGHT starts being transferred to the front end. A 2k pound tractor with 750 pounds of ballast/weight with 1k pound in the bucket puts almost 4k pound on the front end when the rear comes off of the ground.

It really is important to add ballast behind the rear axle to take some stress of the front end... but make sure you have enough! Too little ballast just adds that much more weight to the front end if your rear comes off of the ground.

Also, remember that driving over rough terrain causes the weight to transfer forward... as does slowing down and/or braking.

rjk

 

[riptides]

I just got in from the back, with the same catastophic failure. Identical is the word.
Will be calling the dealer in the AM. I think I just rolled 440 hours.

Very disappointed.

 

[Verticaltrx]

I just got in from the back, with the same catastophic failure. Identical is the word.
Will be calling the dealer in the AM. I think I just rolled 440 hours.

Very disappointed.

If it broke like the one in the first post its not that big of a deal to fix(not that it makes it okay). I'm not sure why these failures have been happening, but I tend to think it is more of a defect than operator error.

All the parts needed cost less than $200 (stub shaft, 2 bearings, seal, etc), and if you are mechanically inclined it should only take a couple hours to fix. Just make sure you set the shims right for the case gear (the WSM tells how to do all this). I can't believe the prices some people pay for parts/labor for relativly minor things. To the average person it seems like a catastrophic failure which is why the dealers take advantage of people and charge them big $$$ to fix things like this.

Also, there was mention that the B21 and other 'industrial' machines use stronger stub axles, this is not true. The part number for the B7800, B3200, B 3030, as well as the B21 and B26 is 32721-57323. The B26 and B21 have a much higher lift capacity on the loader than the other B-series and are often beaten much harder (think rental machines), and this type of failure isn't that common with them. Just bad luck/defective part IMO.