Mowing Breaking BX Blade Bolts

[SPYDERLK]

If the missing hex feature is the problem, why were there no issues for 2 years? I will try and get some more pics when I take the deck off

Did you read the post? ... Because something changed when they took off the blades. Maybe they lubricated the spindle threads making the bolt easier to turn. Then every time the blade encounters a sudden resistance and slips a little it drags the easier to turn bolt along with it causing it to tighten. It doesnt take much extra turn on a tight bolt to stretch or break it. These bolts are very hi grade and wont stretch much before they break.
larry

 

[radioman]

I been thinking about this all day. How in the world would a tough blade bolt snap like that? It dawned on my just now an possibility, but I could be wrong. what if the bolt hole in madrel is full of dirt or something hard inside making the bolt stick out a bit more or maybe the bolts were too long bottoming out and that extra torque to compress the washer just right to hold blade. This could result in the twisting/weakening the bolts.

I dunno- its just a theory that could merit a few moments to look into so it can be dismissed.

 

[dodge man]

I have no idea what the problem is, there are a couple of good ideas floating around. I might try and go to another dealer and get three new bolts. Maybe they aren't giving your the right bolts. Maybe they are giving you bolts for a 60" deck and they are different? Maybe they did get a batch of bad bolts? If you go to another dealer the bolts might cure your problem.

 

[SPYDERLK]

I still have to pull the deck back off (I hate doing that) but here are a couple pics of the carnage.
View attachment 331191

The broken bolt shows stretching.

 

[logdog]

Autopsy pictures

 

[logdog]

I should also note the bolts have come from multiple dealers. The first couple came from the selling dealer, one came from the next closest dealer because my selling dealer was out of stock and one came from the dealer by my work since I cant get to the selling dealer during the week.

 

[SPYDERLK]

You need to get the dealer where the problem started and Kubota involved. This problem cannot be unique to your mower, but lurking on all with that design. Kubota will have encountered it.
larry

 

[SPYDERLK]

Autopsy pictures
View attachment 331583

Thats too much stretch for it to be a very hi strength bolt. Id say Gr5/8.8 or less. When mine snapped on tightening there was very little elongation. I figured Gr8/12.9. ... [strange] :confused2: ... I did replace my bolt with a standard 8.8 grade and have had no trouble tho. But then the design of the 54" mower prevents any possibility of further tightening from incremental blade slippage, by use of that hex washer I referred to.
larry

 

[CHDinCT]

Maybe a stupid idea - not familiar with your 48" deck, but can your dealer order you a set of the hex washers to use on your 48"er?

 

[SPYDERLK]

Maybe a stupid idea - not familiar with your 48" deck, but can your dealer order you a set of the hex washers to use on your 48"er?

Wood be good if those spindles have a hex nose for the washer to engage. It doesnt look like it from the picture he just posted.