Fatigue break on X900 front bumper

BiffNH

Well-known member
SUPER Site Supporter
After three seasons of plowing the bumper snapped while plowing. I have a Boss V-plow and I guess the weight of it plus the forces of plowing have been too much for the thin tubing at the base of the bumper. I am disappointed that Kubota made the bumper with such thin-walled tubing.

Even though I have a wire feed Hobart, I am taking it to a professional so he can figure out how to reinforce it. As you can see from the picture the right side snapped and the left (driver's) side is about to break. I'll post pictures after the repairs are made.
 

Attachments

  • IMG_0475.jpg
    IMG_0475.jpg
    20.2 KB · Views: 127
  • IMG_0476.jpg
    IMG_0476.jpg
    20 KB · Views: 124

Doc

Admin
Staff member
Gold Site Supporter
Pushing snow can sure be hard on equipment. Good luck
 

bordercollie

Gold Site Supporter
Gold Site Supporter
I wonder if you'd be better off to start from scratch with higher quality metal?
That, as you stated, is sure thin.
bordercollie
 

ovrszd

Well-known member
Someone, I'm assuming Kubota's engineers, decides how much force a given part will withstand before it fails. Then they design that part with those specifications the cheapest route.

In regards to this part, it's accomplished by using a different grade of metal. It's not mild steel. It is much more brittle. This allows them to use thinner material of that grade.

End result is lighter weight, less expensive, while meeting the specifications.

If the factory welds were properly applied and failed welding it again will not eliminate the problem. Might accomplish that by adding some small angle braces near the weld. This spreads the load over a larger area of the thin tubing.

Anxious to see what your welding shop comes up with. Thanks for posting the pics!!!!
 

Peanut

Well-known member
SUPER Site Supporter
yea that material is to thin.looks like it broke before the weld .the heat weakened the thin metal.I would just scrap the stock one and have welding shop make new one.they can use old one as templet so that would save alot of money.if you can send a picture of entire front bumper I can tell you about what they should charge you.
 

BiffNH

Well-known member
SUPER Site Supporter
The heavy Boss plow certainly pushed the limits of the bumper. A top-notch welder told me that the bumper was not designed to take the weight and forces of the plow and snow. He did not want to "beef-up" the joint (the weld did not fail) because he is afraid that the forces that broke the metal will just be transferred further into the frame and cause even more damage. I do a lot of plowing with it and after three years I guess I should expect some fatigue. I am not hard on the machine - in fact I am quite conservative. It is just a lot of dirt road to keep clear. Thanks to everyone for chiming in.
 

BiffNH

Well-known member
SUPER Site Supporter
I am picking the machine up tomorrow and will take photos. It will just be a good weld. The welder said it is best that it re-break there in time. Perhaps this is something that Kubota will redesign and make a retrofit replacement for the bumper.
 

BiffNH

Well-known member
SUPER Site Supporter
I picked my machine up this morning. Good welding job - much better than I can do! I think the fillet will help strengthen the connection. I'll just have to keep an eye on it from now on.
 

Attachments

  • IMG_0480.jpg
    IMG_0480.jpg
    19.9 KB · Views: 87
  • IMG_0481.jpg
    IMG_0481.jpg
    20.8 KB · Views: 86

avantiguy

Super Site Supporter
SUPER Site Supporter
It does look good. I can see from the mount why that area stress cracks. There's a lot more leverage on that area than my Curtis/Kubota mount.

Personally, I would have welded a piece of angle/strap/channel from the bottom horizontal bar to the upper horizontal tubing to transfer the load directly spanning the high stress area on those welds but I'm no stress engineer.

Nice work, Bob
 

bczoom

Senior Member
Staff member
Gold Site Supporter
I don't even have a plow and mine is cracking at the same location. It seems to just happen as I haven't even hit anything.
 

Alaskanassasin

Senior Member
Site Supporter
It does look good. I can see from the mount why that area stress cracks. There's a lot more leverage on that area than my Curtis/Kubota mount.

Personally, I would have welded a piece of angle/strap/channel from the bottom horizontal bar to the upper horizontal tubing to transfer the load directly spanning the high stress area on those welds but I'm no stress engineer.

Nice work, Bob

Yep! ^^^^^^^
 

Kanook

Active member
Another hmmmmmm!!!!...Is this part of the grill guard because the front of mine looks nothing like this...My blade mounting hardware bolts directly to the frame.
 

Kanook

Active member
Another hmmmmmm!!!!...Is this part of the grill guard because the front of mine looks nothing like this...My blade mounting hardware bolts directly to the frame.

.....and if memory serves me correctly, the installation instructions for the blade said to remove the grill guard (if present) prior to installing (for the Blizzard blade).

I've hit obstacles while plowing snow that would tear the guard clear off if the blade were attached to it...are you sure that your blade isn't meant to attach directly to the front of the RTV frame?
 

hondajoe

Member
Bumper breakage

Just checked mine ok for now I was kinda worried because I use my bumper for lifting.But at the bigger tube 72 inch john deere v blade gotta have some green.Joe
 

BiffNH

Well-known member
SUPER Site Supporter
I was curious about that as well. Looks like the grill guard was pushed rearward and broke?

No, it never hit anything. It broke due to strain on it from the plow. It did not get push back, just the weight of the plow pulled it down after it snapped. Just had to jack it up - not much force needed - and the break lined up perfectly.
 

BiffNH

Well-known member
SUPER Site Supporter
.....and if memory serves me correctly, the installation instructions for the blade said to remove the grill guard (if present) prior to installing (for the Blizzard blade).

I've hit obstacles while plowing snow that would tear the guard clear off if the blade were attached to it...are you sure that your blade isn't meant to attach directly to the front of the RTV frame?

No, the Boss push frame is designed to attach as is. The pushing force of the plow works directly on the frame, while the weight of the plow hangs on the bumper. Kubota dealer installed it and Boss designed the whole system. It is installed as designed.
 
Top