Can't get stump jumper off brush hog

strum456 · May 26, 2014

I need to get the stump jumper off of an old brush hog. This is the big hub that the blades bolt to. The shaft coming out of the gear box is splined and the stump jumper slides over the splines.

So far I:

1. Flipped the whole thing upside down with the high lift and set it on some big steel saw horses.

2. Soaked the splines with PB blaster over a long period of time.

3. Made a puller out of a big steel plate and a couple 1/2" bolts.

4. Heated the hub with oxy / acetylene

5. Pounded with a sledge until I was out of breath

6. Hung the whole brush hog from the hub while cranking the puller with an impact gun, heating and more pounding.

What is left?

ns_in_tex · May 26, 2014

Were you able to get the nut off? If so, I would remove the lock washer, put the nut back on but leave about 1/4" clearance ( about the thickness of the lock washer) then turn it right side up and hook it to my tractor. Then run the pto. Probably just bump it until it fell down on the nut. This has worked for me. If you have not been able to get the nut off, let me know.

I also use a 50/50 mixture of Acetone & Automatic transmission fluid, in a spray bottle for breaking seized parts loose. For the acetone, just go to walmart & look for finger nail polish remover and get the one that says 100% acetone. I read that in a test, this worked better than all the items sold for this at autoparts store.

whis · May 26, 2014

wedge a couple of broads under the stump jumper across from each other, then with nut on shaft to protect the threads hit with BIG hammer

ns_in_tex · May 26, 2014

I can feel for you.

We had another one that the splitter gear box was out & wanted to make a tree saw out of the outside gear boxes, so was unable to run it with a loose nut. We did most everything you have done above. We were able to get the stump jumper pan off, but the 1x4 bar & spindle hub was still on. We built a puller with 4ea 5/8 bolts to use a 20 ton hydraulic jack. We pulled the bar off the spindle hub where it was welded on, but the hub stayed on the spindle. So we had to get the puller under the hub. We maxed out the 20 ton jack & it did not come loose until after we had hammered on the sides of the hub, with the 20 ton pressure on it.

If you do this, be sure to leave the nut on to catch it, when it pops loose.
Good luck,

strum456 · May 26, 2014

ns_in_tex said:
I can feel for you.

We had another one that the splitter gear box was out & wanted to make a tree saw out of the outside gear boxes, so was unable to run it with a loose nut. We did most everything you have done above. We were able to get the stump jumper pan off, but the 1x4 bar & spindle hub was still on. We built a puller with 4ea 5/8 bolts to use a 20 ton hydraulic jack. We pulled the bar off the spindle hub where it was welded on, but the hub stayed on the spindle. So we had to get the puller under the hub. We maxed out the 20 ton jack & it did not come loose until after we had hammered on the sides of the hub, with the 20 ton pressure on it.

If you do this, be sure to leave the nut on to catch it, when it pops loose.
Good luck,

Yes, this is where I'm at. I had my puller on it with two 1/2 bolts just about as tight as my impact gun would make them without stripping. Just that alone has to be tons of force. Then I hung the whole machine from the puller with my highlift. Then I heated it and pounded on the shaft (through the home made puller) with a sledge. I have an Enerpac, which is rated more than 20 tons, BUT I think it would just bend the stump jumper.

Maybe some kind of penetrating oil would work? The way it sits, there is a reservoir between the hub and shaft that can be filled with oil so it soaks into the splines. PB is obviously not cutting it. I started this project back in October. It was sprayed with PB then. Still no progress. I was thinking of trying an acetone mixture as mentioned.

pmsmechanic · May 26, 2014

Leave your puller on and warm the hub up enough to melt wax and let it soak in. Tighten up the puller and come back the next day and repeat if it isn't off already.

RumT · Jun 1, 2014

I was in the same boat. Heat. Twelve feet of prying lever. Heat n hit. Heat n pry. Nothing. I put the mower upside down on an old tractor tire. For three days I kept the cavity where the shaft comes up (down) through the stump jumper filled with Ed's Red. I wrapped a chain around both blades and routed it over the top of a 12T bottle jack, with the jack sitting on the castle nut installed upside down to provide a pad.

Popped right off.

ME83 · Jun 2, 2014

I was in tractor supply the other day and one of the guys who works there was telling me about a new penetrating oil by WD-40. Something about you heat the part and then spray it with the oil and it seeps right in as it cools. He didn't try it yet but he had numerous customer that swear by it, saying it works much better than PB blaster. I bought a can, but haven't tried it yet either.

RedNeckRacin · Jun 3, 2014

I had a simliar problem, but I used the bottle jack out of my pickup and ran a chain over the blade holders. Basically the stump jumper in my MX10 looks like a doughnut and i wrapped a chain over both blade holders to make a cradle. Put the jack in and put some pressure on it, popped it right off.