BBS Help!: Broken Bolt Syndrome

[FTG-05]

This is the middle blade trunnion for my Kubota ZTR ZD326.



I have a welder (Lincoln SP-175Plus MIG) and 5/16" nuts but no left hand drills or easy-outs. I don't know if anybody in Fayetteville will have them either. I may have to go into Hsv/Grainger to get them if needed.

How screwed am I?

I have to go into Fay tomorrow to the Kubota dealer to replace the bolt anyway.

 

[TractorGuy]

I would first try unscrewing with a sharp punch. Just tap counter clockwise around the edge. It's a big enough bolt you wouldn't have to drill dead center to get something in it to unscrew it. But if you drill it for an extractor try to get as center as possible and drill all the way through. A large concrete nail makes a pretty good easy out. Make sure you don't lean on any hardened extractor hard enough to break it off in the bolt. You are screwed if you do that.

 

[FTG-05]

My bad: I forgot to mention I tried that already. I can hit some more tomorrow but I'm not hopeful.

And I didn't realize the first pic was so bad, but there is no flat surface on the bolt body. How do you get the drill to drill on center?

 

[KWentling]

Use a center punch to get started in the center and then angle your drill as needed to keep it centered. A town that size should have Mac Tool and Snap-On trucks. They would have the left hand bits and easy outs. Don't try to drill with a dull bit. You'll work harden it and then you will need a carbide bit to get started again. If you resort to using the welder, be sure to put your ground on the spindle so you aren't grounding through the bearings.

Was an impact involved in this? I use the impact to take them out, but hand tighten them to avoid that. Good luck.

 

[LouNY]

How big is the broken bolt, I'd get a nut the same or close to it's diameter,
fire up the welder, weld the nut to the broken stud, put a socket and breaker bar on and
start working it back and forth and it should come out.
welding nuts on with a stick welder is my preferred way to remove broken bolts.
The last one I welded on the head had rounded of on so I laid a large nut over it, welded it on turned it right out.

 

[KubotainNH]

How big is the broken bolt, I'd get a nut the same or close to it's diameter,
fire up the welder, weld the nut to the broken stud, put a socket and breaker bar on and
start working it back and forth and it should come out.
welding nuts on with a stick welder is my preferred way to remove broken bolts.
The last one I welded on the head had rounded of on so I laid a large nut over it, welded it on turned it right out.

This ^^^ You should have enough space there to get enough penetration. I've done it more often with a wire feed welder, I like the control of the small wire. The plus is that the heat from welding usually breaks the threads loose and it just spins out.

 

[mrmikey]

As others had said, welding is the better way, least ways in this case. Is that a crack running back along the shaft at the 11 oclock position?..............Mike

 

[GLyford]

Harbor freight carries a set of left hand bits...but I'd try welding a nut on 1st. Once you get it on there, try "rocking" it with short turns back and forth to clear the threads, rather than just turning like crazy. If you twist it off, grab another, lather rinse repeat. Hit the threads with your spray of choice once hot, it will penetrate even better than when cold.

Left Hand Drill Bit Set 13 Pc

 

[4570Man]

As mentioned several times that’s a good candidate for welding out.

 

[FTG-05]

Use a center punch to get started in the center and then angle your drill as needed to keep it centered. A town that size should have Mac Tool and Snap-On trucks. They would have the left hand bits and easy outs. Don't try to drill with a dull bit. You'll work harden it and then you will need a carbide bit to get started again. If you resort to using the welder, be sure to put your ground on the spindle so you aren't grounding through the bearings.

Was an impact involved in this? I use the impact to take them out, but hand tighten them to avoid that. Good luck.

I used a 3/8" impact ratchet to put them back on the last time I had them off. When I investigated why the center blade wasn't cutting, I found the blade was loose and when I went to tighten (iwth a 1/2" ratchet) it fell apart like a cheap watch.

I *assume* that an impact with a rock or something like caused the initial failure.

Thanks,