Replacing the Bushhog Blades

We have a few acres in the back that doesn't get much attention, except by the birds. They eat warthog berries then poop them from trees and fencelines. Then, more warthogs grow. I don't like them. So I bushhog them down. For many years, I'd do it when convenient for me, which happens to be exactly when its convenient for the warthogs - when their little berries are out ready to be eaten by the birds or spread even wider by the mad thrashings of a bushhog. So now, in that little back land, it is covered with warthogs and its cousin, crappy bush. Warthog grows about three feet in height per year and about an inch in diameter. It is shallow rooted and a single plant makes about 56-67 shoots. Crappy bush grows about the same height and diameter per year, with about five shoots per plant but is much deeper rooted. This year (March 2012), I thought I'd mow 'em all down before they started seeding.

As I was mowing down the warthog and crappy bush, I noted the 6" bushhog (actually an International Worldtech Industries IM600 - no affiliation to International Harvester) became way out of balance. That happens when the blades both swing to one side. But this time I couldn't get them to balance. I got off the International Harvester 574 and discovered one of the blades was missing. Seems that the particularly dense, 15' crappy bush area I was mowing helped to loosen or break a blade nut, causing the blade to fall off.

So, I ordered new blades from a place on-line called DN Equipment. Cost about $150 for two 31" long by 4" wide by 1/2" thick big hunks of steel, weighing about 25 lbs each. Also had to get new 5 lbs bolts. So on March 11, 2012, I lifted up the bushhog and set it down on these cinderblocks, 4x4 posts and jackstands. Meanwhile, the tractor hydraulics were still holding it up. The tractor hydraulics would have held it fine - they don't leak down and are pretty reliable. But I put all this other stuff under it just in case. I also put a tractor jack under it as well.

This is the flywheel that holds the blades. See the one still there? Now, how to get that bolt off. I started by trying to jam a piece of steel between a bar on top and the little apons in front and behind the flywheel. When that didn't hold, I put a bolt in the free hole, hooked a chain to it and wrapped it around the top of the bushhog. That worked well. But I still couldn't loosen the nut on top of the remaining bolt. So I pulled out the blue wrench (acetelyne torch) and cut off the head of the bolt. As I was jerking the blade to free it from the burnt stub of the remaining bolt, it suddenly broke free and smashed into the top of my head. Three hours, about a pint of blood, and two staples in my head later, I decided to cut the nut off. But first I would turn the bushhog on its back, which would need another day.

The blade on the right is the one that smashed my head - I'm happy it was only going a few mph - full tilt would hurt lots more. New blades to the right are stacked up. Bolts are in the plastic bag.

While I'm at it, I am removing the dogleg bolt that should be a shear bolt but is actually an anti-shear bolt. Seems its bent enough to not break. So here I'm drilling it out. More later.

Here it is March 17 and its time to cut the rest of the blade bolt off. For this, I decided to lean the body against a tree. I loosened the bars that go from the hitch to the tailwheel so they wouldn't get bent. Then used the EF-3 with the forks to lift the right edge and carefully place the top against the tree. I chained the top to the tree so the wind wouldn't blow it over on me. I also chained the bottom after this picture so it would not slide out. I had the cutting torch handy in the G-Cart.

A before and after picture. The top shows the nut that I couldn't loosen when under it. See the wire around the shaft? That happened when I vacuumed up about 300ft of electric fence wire about six years ago. Guess I didn't get it all cut out. The bottom half shows the nut after I hit it with a little oxy and acetylene. Works good.

After I did all this, I realized the bolts are interference fit and wouldn't just fall out. Then I discovered the little crown nut that holds the flywheel on can be removed pretty easily. With that off, I beat out the old bolt. Now, I just have to attach the new blades. Then put the flywheel back on. Next time I change the blades, I'll do that, saving me about four weeks.

All bladed up and mounted. Note the check mark on the bottom of the deck. That's the mark I made when I used the EF-3 forks to lean the deck against the tree. See the frame bars sticking out the back? Two of those fold back up and go to the hitch.

Letting it down easy. Its almost down here. I used a chain connected to the frame and lifted it up. Then I lowered it while backing up to fold it down gently. This actually worked pretty well.

Back to the stuck shear bolt. After I got the blades on, I took it for a spin to break the bolt while I attacked some more crappy bush and wart hog in the back. When doing it, I heard this horrible metal on metal screech. Turns out that was the PTO yoke turning on the shaft, wedging itself onto the shaft forever. No matter what I did, I could not break it free. I even tried chaining the bushhog to a tree and using the tractor to pull this yoke off. After realizing it was stuck, out came the blue wrench once again. Here is the result. The cast iron part cut pretty well as did the forged steel sleeve inside the yoke. The gearbox shaft was barely touched. I cut the other side and banged on the cut with a cold chisel to break this yoke off. I think I have a spare somewhere.

This is the gearbox shaft after the yoke-ecktomye. Just a little stray torching, but all in all, a survivor.

This took me about a day. I rescued a replacement gearbox shaft yoke from a bent PTO shaft (the one on the right). After about three hours, I figured out how to get the cross (or spider) off - it took a lot of clamping, vicing, and some hammering. I resisted the urge to use the torch! This picture shows the good shaft yoke (left) ready to be mated to the replacement gearbox yoke. The little inset picture shows a bearing cup with the loose needle bearnings - 26 to be exact.

Assembling the replacement universal joint. Here, the vice squeezes the bearing caps into the yoke for the second time. The first time, one of those pee-wee little needle bearings dislodged from its greasy bed and lodged down in the bottom of the cap, preventing the caps from sealing.

Here are some extra parts, I'll consider consumables. Clockwise from the yellow thing: The yellow PTO guard that I melted during the first attempt to heat out the shear bolt. The blade bolt that came out creating this ordeal. Old electric fence wire wrapped around the flywheel shaft for six years. Molten bolt covered gravel. Two halves of the original gearbox shaft yoke. Some retaining circlips from the original U-Joint bearing caps along with the remains of the original U-Joint cross/spider. To the far right are the original blades, the top one responsible for bashing my head.

Here's what that 25lb blade, some gravity, and a gentle tug created in my head.

A week later and I got the head staples removed. They gave me the staples and the little tool for pulling them out. The banana demonstrates the relative size of the staples. I can't really figure out what the staples looked like pre-removal.

Beat me to the Phone