Removing bent shear bolt

[sghoghunter]

A couple months ago I was given a old 5 foot bush hog brand rotary mower. First thing I done was remove the rusted out stump jumper and change the blades and bolts and it the working on it I noticed that someone has put in a grade 8 bolt in where the shear bolt goes where the shaft goes on gearbox. Also I’m thinking it’s already bent a little bit cause it’ll wiggle a tad each way but won’t turn all the way or come out. Has anyone ever ran into something like this? Do ya think if I heat the bolt red hot that it’ll loose it’s temper?

 

[Milkman]

Pictures??

I suggest grinding off one end and use a large punch to drive it out.

 

[livinoutdoors]

Hammer n punch?

 

[Shotgun1]

Your idea of heating to red should soften it a lot. Will be a big help in case you have to drill it out

 

[mallardsx2]

Cutoff wheel…

 

[Big7]

Cutoff wheel…

Best bet is a cut off wheel and I'd be SURE to replace it with an actual shear pin. That's SUPPOSED to be the weak point that keeps you from busting the rest of the drive train.

Sounds like whoever had it got tired of sheering pins or just put what was handy following a break down in the field to get by and didn't replace it properly.

I used to put pieces of 3/16" aluminum welding rod in my 5 horse boat motor to keep from busting props in the rivers and swamps.

 

[Ruger#3]

I agree with grinding or cutting off and punch it out.

My method is a bit different, what I did on aircraft. Call your auto parts and look for CRC Freeze Spray, it’s liquid nitrogen in a spray can. Heat up the outer fitting, not the spline, when you got that part hot spray the bolt with the nitrogen. It’s -65 degrees so be careful about splash getting on you it burns. Be ready to drive the bolt before either side changes temperature much. It will give you some wiggle room around the bolt.

 

[Big7]

Best bet is a cut off wheel and I'd be SURE to replace it with an actual shear pin. That's SUPPOSED to be the weak point that keeps you from busting the rest of the drive train.

Sounds like whoever had it got tired of sheering pins or just put what was handy following a break down in the field to get by and didn't replace it properly.

I used to put pieces of 3/16" aluminum welding rod in my 5 horse boat motor to keep from busting props in the rivers and swamps.

And if the pin is still going through both sides, It's not bent enough to keep you from driving it out if you cut the head off with a wiz wheel.

 

[sghoghunter]

Pictures??

I suggest grinding off one end and use a large punch to drive it out.

It’s not bent on the outside where you can get to it I’m thinking it’s hit something in the past and bent the bolt inside there just enough that it won’t come out. I’ve tried beating on it and I’ve tried backing it out and it’ll twist maybe a 1/16 each way then binds up

 

[Milkman]

If you have an impact wrench you might use it and a heavy duty socket and either get it to spin or shear off.

If not try as I suggest in post one. Grind or saw off the threaded end.

The jarring of an impact wrench of striking the sawed off bolt should make it give and push through. If you don’t have a big punch a bolt might work. I suggest at least a 3 pound hammer.

 

[livinoutdoors]

It’s not bent on the outside where you can get to it I’m thinking it’s hit something in the past and bent the bolt inside there just enough that it won’t come out. I’ve tried beating on it and I’ve tried backing it out and it’ll twist maybe a 1/16 each way then binds up

Hammer it back in far enough to cut the head off, then use a punch to drive it the other way out.

 

[Doug B.]

I hope this is not too far off topic, but is it not supposed to be a grade 8 bolt? The reason I ask is because a camper that I have has got a grade 8 bolt in the drive shaft for the slide out. It has sheared twice on me in eight years. It is what was in it when I bought it so that's what I replaced it with. Is a grade 8 more or less brittle, or hardened, or whatever the term may be, than an actual shear pin?

So, if you buy something used and something breaks or wears out, trying to stay on topic here, how would you know what grade bolt to put in it?

 

[Milkman]

I hope this is not too far off topic, but is it not supposed to be a grade 8 bolt? The reason I ask is because a camper that I have has got a grade 8 bolt in the drive shaft for the slide out. It has sheared twice on me in eight years. It is what was in it when I bought it so that's what I replaced it with. Is a grade 8 more or less brittle, or hardened, or whatever the term may be, than an actual shear pin?

So, if you buy something used and something breaks or wears out, trying to stay on topic here, how would you know what grade bolt to put in it?

I prefer a softer shear bolt on something like a direct drive rotary mower that can lock down instantly and send that shock into the drive train.
The best overall solution on a rotary mower is a slip clutch.

 

[tucker80]

Get the nut off and drive it out with a 1/2" bolt. If it doesn't move, get a bigger hammer.

 

[Crakajak]

Be careful to not overheat it if you do heat it up.You might be replacing the u joint.

 

[NE GA Pappy]

cut that nut off with a cutoff wheel on a grinder, turn the end you just cut off straight up. Squirt some WD40 or something in there to give it a bit of slicking up... get someone to hold a short bolt on top of the cut off bolt with a big pair of visegrips or channel lok pliers. Make sure the short bolt is smaller than the bolt you are removing. Draw back with a 3 to 6 lb hammer and frail the dickens out of it. Once it moves get a longer bolt and keep smacking it until it drops out the other side

or.. if you feel pretty lucky, before you start smacking it with a hammer, get a drill bit about 1/16 smaller than the bolt and drill down in the bolt for an inch or so

 

[tucker80]

I've had them shear and leave a bur causing it to hang up. I think they kind of half shear sometimes and you cant drive it through because the edge of the bolt is hitting the shaft on the gear box. You may be able to pry it out after you get the nut off.
Really ain't a good answer except to get violent and use lots of sentence enhancers. It'll come out eventually.

 

[Mauser]

I wouldn’t heat that at all. It’ll mess up the seal on the gear box. I’d try to drive it out with a punch and maybe put an impact on it and back it out.

 

[bany]

Or turn it vertical and with an impact and lubricant get the thing moving. Heat Would be a last resort. I imagine you got it out by now!

 

[bassboy1]

I don't think I'd be doing any cutting on that. I think Tucker is probably right in that it's half sheared. If that's the case, I'd take a cordless impact and loosen the bolt until it breaks. If it's half sheared, it should break at the weak point down inside the hole. Double nut the other side and try the same (probably in tighten mode, so the nuts don't come loose).

Best case scenario, the bolt breaks right at the joint on both sides then you can separate the parts and just have to drive the piece out the center without fighting the misalignment of the outer part.

Worst case, the head breaks off, and you're right where you'd be by cutting the heads off anyway.