Bush Hog Blade Removal Help

[cmatthew]

Hey guys,
Saw the post on sharpening bush hog blades and I thought I see if anyone had a solution to this problem---
A buddy of mine (Captain Destructo) called me the other day to take a look at his cutter. He said it was making an awful racket while cutting. Turns out he managed to hit something solid enough to bend the deck where the gearbox mounts and now the blades hit the bottom of the mower deck (5' width, I think) on the left side.
I tried to remove the blade in order to take off the gearbox and hammer/shim the deck straight, but I couldn't get the blade/stump jumper pulled off the shaft. I've soaked the splined shaft with liquid wrench and even put a torch on it with no luck.
I went by there this morning and found that my buddy had flipped over the mower deck and hung it with chains attached to the blades from an engine hoist. He was hitting the shaft with a 5 lb. sledge hammer hoping the hammer and weight of mower deck would cause it to drop off. I'm not sure what he would have done when the deck landed on his legs/feet. I took his hammer away from him and went to work.
Anyway, sorry to ramble on with this and if anyone has a suggestion I'd greatly appriciate it.

Thanks,
Bryan

 

[firemanpat2910]

maybe try the wax trick? ( thread on here ) Was he hitting the shaft? If he mushroomed it too bad you might never get it off. can you just heat the deck and bend it back with the blades/stumpjumper still on? or loosen one side of gearbox bolts and shim it?

 

[cmatthew]

I don't think I've heard of the wax trick? I haven't checked to see if he did any damage to the shaft using the hammer, but I would be shocked if he didn't. I actually saw him splinter one end of a 2x4 one time while trying to nail it to the wall of his shop.
I checked to see if the bolts could be removed from the gearbox w/o removing the stump jumper. The nuts are recessed under the the deck and I haven't figured out how to get to them. I had thought about possibly making a hole big enough for a socket to go through in the stump jumper but I'm not sure how smart that would be?

Bryan

 

[firemanpat2910]

do a search for "wax used on rusted parts" or a search for posts from "pinemountanman" I have used this trick years ago with good results. Basicaly heat the shaft, melt wax into the joint and let it cool. then the parts are easier to get off.

 

[cmatthew]

Well that sounds like a pretty cool trick---I've got plenty of rusty things lying around. I'll give that a try on the bush hog tonight before I do anything more drastic. I guess I'll check for any damaged threads and/or mushrooming of the shaft too while I'm at it. Thanks for your thoughts and advice! I'll let you know how it goes.

Bryan

 

[Bird]

From what you said, I am assuming you got the big nut off the bottom end of the gearbox output shaft, but cannot get the stump jumper off the splined shaft. I'd use something like a gear puller. I made a home made type of rig once to get a stump jumper loose with a short piece of C channel iron and two big C clamps. I put the nut back on the shaft just about flush with the end. That serves two purposes; one is when it does come loose it doesn't fall on you, and the other is so you cannot mushroom the end of the shaft.

 

[sandman2234]

http://www.tractorbynet.com/forums/parts-repairs/97738-wax-used-rusted-parts.html

Wax trick,
David from jax

 

[Saxman]

Well I think your buddy has a big problem. From my 25 years dealing with mowers we mow state highway rights of way with I have found that if the deck is sprung where the gearbox mounts it is almost impossible to fix. The deck is usually reinforced in that area and if you do mess it up it is that much harder to staighten and almost impossible to make it mow evenly. He has probably mushroomed the end of the shaft anyway.

 

[cmatthew]

Well, I checked out the damage last night. Looks like he chipped a small piece off the end of the shaft and its definitely messed up enough so that the nut doesn't want to go back on. I'm not sure if it's just the squashed threads from a glancing blow from the hammer or a mushroomed shaft but either way it doesn't look good.
The deck of the mower is definitely reinforced where the gearbox mounts and I don't know that I'm man enough to straighten it out if the gearbox was out of the way. My buddy is still convinced that he almost got it to come loose if only he could take a few more swings w/ the hammer----he's not getting back the hammer!
I guess at this point I better see whether or not the end of the shaft can be salvaged before I go any farther w/ the original problem. If the shaft isn't damaged much past the end can I take an angle grinder to it and then clean up the threads or would that be a bad idea?
Thanks to all for the great input and ideas. I'm really glad I found this website so I don't have to "suffer" through stuff like this alone.

Bryan

 

[MikesTractor]

You still need to get the stump jumper off before you do anything to the shaft. Then remove the gearbox and lay it to the side. Now see if you can fix/straighten the deck. If you can't fix the deck, then it is useless to try and fix the shaft.

If you can fix the deck, then see if you can straighten up the threads on the shaft. If you can't clean the threads up, take the bottom shaft out of the gearbox and carry it to a good machine shop and let them cut the threads back into the end of the shaft.