bush hog blade bolt removal

[bruski]

I'm changing the blades on my little Bush Hog sq480 as they're pretty beaten up and I want to do some pasture cutting. I've gotten the nuts and washers off thru the view holes using PB Blaster and a cheater bar (thanks to info on this site) but now the bolts seem to be frozen in unless I'm missing something. Beneath the mower the bolts appear to be round headed and I've tried a pipe wrench to loosen it and I've beaten gently on the top, but no move. They are supposed to drop out aren't they? Is there something to be loosened first? Have I missed something?

Bruski

 

[TomWhite]

Generally (at least on the ones I've owned) the bolts have a square section between the head and the threaded part of the bolt. This fits in a square hole in the stump jumper, and is the reason you don't need a second wrench/socket or whatever to take them off or put them on. Try to find a piece of pipe or something similar, smaller in diameter than the bolt. You can use it sort of like a punch, along with a mallet, on the end of the threaded section on the bolt and likely get it out that way.

 

[sweettractors]

I'm changing the blades on my little Bush Hog sq480 as they're pretty beaten up and I want to do some pasture cutting. I've gotten the nuts and washers off thru the view holes using PB Blaster and a cheater bar (thanks to info on this site) but now the bolts seem to be frozen in unless I'm missing something. Beneath the mower the bolts appear to be round headed and I've tried a pipe wrench to loosen it and I've beaten gently on the top, but no move. They are supposed to drop out aren't they? Is there something to be loosened first? Have I missed something?

Bruski

There is usually a key on the blade bolt to keep it from turning. After removing the nut and lock washer, you should be able to knock them right out the bottom. If no-go, heat always works. Ken Sweet

 

[Farmerford]

Bruski:

Ken Sweet is correct; the shoulder of the bolt has a "key" formed by pinching the shoulder of the bolt. The key fits into a slot in the side of the hole in the bladeholder.

The blade bolt has probably rusted in the hold in the blade holder.

Just hitting the bolt lightly from above, through the hole in the deck, does not deliver much shock to the bolt because the blade holder and the mower deck flex enough to absorb the sharp blow.

Support the end of the blade holder next to the bolt with a solid object. A block of steel is preferable, but a hydraulic jack works about as well.

Then screw the nut back onto the blade bolt until the end of the bolt is flush with the nut. Put a steel rod larger in diameter than the bolt (1 1/4" I would guess) on the bolt head and nut and then whack it hard with a three or four pound hammer.

If that does not work spray some PB Blaster on the bolt and come back tomorrow for a second round.

Ken Sweet is also correct about heat. I don't think either the blade bolt or blade holder are heat treated, so heat will not hurt them. I favor heating the blade holder so that it expands and then hammer the bolt out before it cools down, but others favor heating the bolt so that it expands in the hole and loosens the grip of the rust; then let it cool and hammer it out.

In either case, put some antiseize on the blade bolts when you reassemble them.

 

[bruski]

Finally got them both out, one yesterday, one today. PB Blaster wouldn't do it, finally did it with lots of heat - let it cool and then simply beat the sucker out. No damage. All is good. Cleaning up the bolts tonight before smearing with antiseize to install tomorrow. BTW, no key, just stuck tighter than, well, tight.

Thanks for the tips.

Bruski

 

[JimDavis]

OK, the bolts on my bush hog just turn in the blade and blade holder. They are a little snug, but trying to turn the nut just turns the bolt too.

How in the world can I get those out, short of a cutting torch?

Jim

 

[aczlan]

Angle Grinder? Pipe wrench on the top of the bolt?

Aaron Z

 

[sweettractors]

Sometimes you can get a pipe wrench on the blade bolt head and hold it from turning. You could also weld a large nut on the head to hold to and of course, the cutting torch is the quickest way to cut off the blade bolt nut. Ken Sweet

 

[Brad_Blazer]

I second the pipe wrench on the bolt head. Plan on a 3 foot cheater bar on each wrench. That was the first use for my 3/4" drive ratchet set from HF.

 

[JimDavis]

Thanks. Good ideas. After reading the posts about sharpening, I'm thinking I don't need to have sharp edges for whacking down the brush...

Jim