PT425 48" Brush Hog Broken Bolt Removal Tip

[ponytug]

Yes, yes, and yes.

The general idea is that you want the heat sink material not to be weldable under the conditions that you are welding. Since aluminum has a low melting point, you want the aluminum to be thick and large to absorb the heat and conduct it away fast enough not to melt.

Copper has a higher density and better thermal conductivity. I have a pair of copper "spoons" made of thick walled copper pipe for starting and ending TIG welds and to back holes to keep air from penetrating the welding areas. You can get fairly heavy pieces at scrap yards by looking for copper bus bars. I have heard of people using brass, but I have never tried it.

Graphite has the highest "melting point". I find it trickier to use, but your mileage will vary...

You can, of course, use this the other way around, e.g. using stainless steel to back up aluminum.

All the best,

Peter

 

[MossRoad]

Hmmm. If I would have attempted it, I guess I'd have just filled in the hole in the blade completely with the welder, ground it down flat, then drilled it out with a hole saw. I don't think balance is too critical on these beasts. I don't think I'd have to back the hole with anything. I'd stand the blade on edge and fill in the bottom of the round and work my way up. I've never tigged before. I've got an arc welder and wire-feed welder. I just use flux core right now. I've got a regulator, but never picked up a gas bottle. I think that might be handy to have VS the slag from the flux core in this situation. I'm planning on doing some body work on my old rusty Suburban, so maybe its time for gas.

 

[woodlandfarms]

So. Stupid me. Don't your guys mower blades have bushings? Mine is basically a piece of 3/4 pipe cut to size.

 

[ponytug]

They do have bushings, but un-greased you can wear through the bushing and into the blade in a day.
I upgraded to sintered, oil impregnated bushings, but greasing them is key for me.

All the best,

Peter

 

[MossRoad]

I've never thought about lubrication on those blades and bushings.... I will now, for sure.

 

[bol4fun]

First timer for changing a broken bolt. I luckily found the spacer, washer, and blade. I have read everything but not comprehending a lot. Where to start? ....big nut with cotter pin?.... 4 motor bolts? I am assuming that the drum on the under side has to come off. Any advice would be appreciated. Thanks

 

[MossRoad]

I bumped up an old thread in the PT forums for reference.

What I do to disassemble my brush cutter is (from memory):

- take off the 4 bolts that hold the motor mount bracket.
- loosen the allen set screw in the lovejoy
- lift the motor, bracket and half of the lovejoy off of the deck and set aside.
- I think there are 5 lug nuts that hold the hub assembly to the deck. Remove those 5 nuts and the entire hub, drum, and blade assembly will drop out the bottom of the deck.
- Lift the deck off of that assembly with the PT and back it out of the way, set down and continue.
- Now you have full access to the inside of the drum to work on the back-side of the broken bolt.

Hope that helps.

 

[MossRoad]

I eventually ended up using a hole saw and cut a hole in the top of the deck in-line with the rotation of the blade bolts. That allows me to stick a socket with extension down inside the back of the hub and remove the jam nuts to change out the blade bolts if they start looking damaged. This only works if the blade bolt head hasn't already sheared off. I kinda decided to just buy a box of blade bolts and change them once a year for good measure.

 

[woodlandfarms]

On my machine i cut holes in the deck to allow access to the threaded part of the bolt. My lock nutz are welded onto the drum so i made a long bolt with a nut partially threaded on and welded in place as a wrench. I line the broken bolt up with the hole and thread the bolt nut tool over the broken bolt and use my impact to drive it out far enough to grab with vice grips. Oh and i found for me grade 5 last longer than 8 as 8s are brittle and the bolts i use are longer than stock

 

[bol4fun]

I bumped up an old thread in the PT forums for reference.

What I do to disassemble my brush cutter is (from memory):

- take off the 4 bolts that hold the motor mount bracket.
- loosen the allen set screw in the lovejoy
- lift the motor, bracket and half of the lovejoy off of the deck and set aside.
- I think there are 5 lug nuts that hold the hub assembly to the deck. Remove those 5 nuts and the entire hub, drum, and blade assembly will drop out the bottom of the deck.
- Lift the deck off of that assembly with the PT and back it out of the way, set down and continue.
- Now you have full access to the inside of the drum to work on the back-side of the broken bolt.

Hope that helps.

Finally got around to working on the bolt. I bought my PT new in 2017 so the newer brush hogs are different. You don't have to take anything off the top of the unit. My son just took his impact gun and removed 5 bolts from the underside and it dropped down and we backed the bolt out with a vice grip. Easy Peavey!
The blades are bent a little so am taking them to a friend to see what his big press will do for them. Evidently the blades are made with a small bend at the ends because when I sat them on top of each other they are both the same????.....but need to work on the other bends. I sharpened them and now have to make sure I mount them in the right direction....forgot how they came off but think the unit revolves counterclockwise. Thanks for the tips