Brush Hog Rotary Mower Stump Bump and Blade Removal – Ranch Hand Tips

removing your blades and your stunt bump
from the bottom of a rotary motor or a brush hog is a lot more difficult than I
could have possibly ever imagined it took me two days to figure out how to
get this thing off and in this video I’m going to show you how you can do it in
less than 15 minutes the problem with my brush hog is that I
actually cracked the stump bump in half underneath our brush hog here and if you
look up in here but you can see this big crack across here and there should be a
steel arm that goes straight across that these blades attached to I don’t know if
I can turn this away you can see it but that steel arm it’s broken through right
in there I actually broke the metal in half as I was mowing and so the blades
were kind of just flopping underneath there for the purposes of this video I’m
gonna show you some of the things that I did do that didn’t work at all the first
thing that you’re gonna need to do is remove the bolt from underneath the
stump up this bolt is a one in 7/16 inch bolt so getting it off you’re gonna need
to use either a very large adjustable wrench or what I did was I went down the
street and borrowed a larger socket wrench from one of our local mechanics
and then I removed that that bolt that bolt is held in by a cotter pin so
you’re gonna remove the cotter pin and then loosen the bolt now obviously when
you’re trying to turn the bolt underneath here this gearbox is going to
spin on you so what I like to do is take a pole some sort or actually a crowbar
works very well because it’s a little narrower and I’ll shove it in there so
that is this spins the crowbar will actually block it from spinning and you
can easily loosen up the the bolt that’s underneath your stump up guard getting
that bolt off is the easy part of this entire process it takes a little bit of
elbow grease but you’ll get that thing off the hardest part is going to be to pull
the stump bump off of the shaft coming out of your gearbox because that stump
up over time has adhered to that shaft it won’t come off very easily
I’ve watched the numerous videos on this on YouTube I’ve seen guys take bolts and
stick them on the underside of the stump up and then slowly tighten down the
bolts of the bumps they were putting the bolts so they were going through the
holes that are in the bottom side of the stump bump or they remove their blades
and use the blade holes and as they twisted those they applied even pressure
and pushed the stump pump away from the deck and off of the shaft from the
gearbox so that is one method that I had seen another method that I actually
liked a little better was there was somebody who had cut 2×4 wedges he used
a sledgehammer to wedge them into the sides of the stump bump and slowly by by
pounding on it with the sledgehammer was able to move it up a little bit and then
he’s stuck in there after it was far enough out he’s stuck in some jacks and
slowly opened up the jacks to help lift the stump bump off of the deck and the
spin and the shaft is connects to the gearbox neither one of those methods was
working for me the problem with my brush hog is that I actually cracked the stump
bump in half I actually broke the metal in half as I was mowing and so the
blades were kind of just flopping underneath there using those methods to
try and remove it was making it worse it was the the metal was just continuing to
bend and it was it wasn’t it wasn’t being productive something that I did do
was I turned the mower upside down I took a cable similar to what you’d see
on a come-along and I wrapped it down into the holes on either Sun that were
on the stump up and I wrapped it around the inside of the stuff up on that shaft
to try and get some leverage to try and pull it now here is my mistake number one when I
couldn’t pull it loose any I tried attaching it to the tractor in the car
and pulling it off of there believe it or not I got frustrated
enough to do this it did not work other methods I tried using crowbars
I’ve tried using hammers I tried a lot of different methods I
even hung the entire mower upside down with that cable method on the boom pole
of our tractor and drove it around the yard hoping that it would somehow loosen
and fall off so I tried a lot of different methods
and nothing was really working but what ended up working for me is really
something that if I had done the beginning would have only taken me 15
minutes I used the torch simple science would
explain that if you heat up a piece of metal that heat is going to cause the
metal to expand and contract what we’re trying to do is get the stump bump off
of the gearbox so by expanding and contracting that metal with heat we were
slowly loosening up the binding that it has created over time of being attached
there I’m not using a welding torch because I’m not trying to cut the metal
I’m not trying to melt the metal what I’m trying to do is just expand it and
contract it with the heat cooling and heating cooling and heating so I used a
propane torch when I held the propane torch around the area for about 10 maybe
15 minutes so I got it very very hot I had it hanging on the back of the boom
Pole still I was able to then take a block of wood put it over the top of the
shaft and whack it real hard I used a flooring hammer but I would
suggest a handheld sledgehammer something that you can get a good hard
whack on it yes
we got so hot smoking it’s what I ended up doing was I had it
hanging off the boom pole and I just kept eating it up and eating
it up with this torch get this thing in here just super hot and then I had a
piece of wood over the top of this which just has a little bit of damage but I
could always fix that and I’ve whacked it but this hammer which is the heaviest
hammer I have is for installing hardwood flooring temporarily what I had done to
fix the brush hog was I took our piece down to a French shop he owns a welding
shop and had him weld it back together really we need to buy a new piece there
are only about a hundred bucks because it’s not ever going to be straight again
it was bent way too much out of shape but at least with it welded together we
could go and finish mowing around the house
very slowly because of some of the methods I had tried before and some of
the whacking that I took on this poor brush hog with a hammer
I had damaged the threads for the bolt when it goes back on so with the threads
damaged and I’m gonna tell you about this because some of you may damage your
threads as well if you get as frustrated as I do with trying to remove this stuff
bump from the brush hog what I ended up doing was I cut off with a saw saw at
the top eighth of an inch to the quarter of an inch of that shaft the threaded
shaft coming out where the stump bump goes on over it and then you screw it
down so I took off the damaged part of the threading where the boat would not
thread on and then I used a file and really kind of smooth it out and helped
get get it to the point where a new bolt would thread on this actually took me about thirty
minutes of time if I had just maybe heated it up and whacked it off the
first time you probably wouldn’t have damage to your threads so we’ve got the
new cotter pin in place I’ve tightened this down pretty tight main thing is
that you get it tighten of thing but this powder pin in there so it doesn’t
spin off I did put a lot of lube on here and on the main shaft to get this to
slide down I’m not using a grease I’m using a loop because you know as a Lube
goes away it’s going to make this really stick on there again like it did
originally and it’s just safe for that way but this thing is still bent – all
heck I don’t think that the the cost of trying to bend it back was justified in
the repair so if it doesn’t work we’ll just take this plate off again you could
really see that bending there right there but we’ll just take the plate off
again and replace it with a new plate and blades but I’m hoping that this
$40.00 fix will at least get us back to mowing temporarily definitely don’t bother
with some of the other methods that I I showed you in this video I’m showing you
those just to show you how frustrated and how attached these stump bumps get
to their brush hogs this there’s a simple method to get it off and that is
with the torch just to use a propane torch get it really hot keep it on there
for about 10 or 15 minutes put a piece of wood over it so you don’t damage your
threads and give it one hard quick whack and I think should pop right off of
there again I was also hanging it from our boom pole so the weight of the brush
hog was giving me a little bit of a factor when I gave it that final whack
it just kind of flopped to the ground and helped separate it so you do need
some sort of way to have pressure on there separating the stump bump from the
brush hog when you when you give it that whack
and however you do that is up to you the jacks seem to work for some guys some
guys use the bolts like I said I’ve seen a lot of videos on how to remove this
some of our great ideas some of them take a long time
heat is the key element to removing these and some sort of pressure to pull
those two apart as you give it away

50 thoughts on “Brush Hog Rotary Mower Stump Bump and Blade Removal – Ranch Hand Tips

  1. I'm a BIG believer in using Kroil and soaking the parts for a few days prior to any removal work.
    No one at our utility used PB blaster.

  2. This odyssey​ was wonderful. You're well on the path of getting an oxy-acetylene torch set-up for reasons. If you must hit a hardened threaded shaft, thread the nut most of the way back on. In this way you beat up the nut, not the shaft. Regardless, brush cutters are a hassle to mess around with as my own odyssey shows. LOL

  3. Replacement Brush Hog Blades
    Replacement Gear Box Rotary Cutter
    PTO Driveline with Slip Clutch
    Propane Torch

  4. Mistake #1 is that you were using non-destructive methods on an irreparable part and lacked an O/A torch to do it how the rest of the world does it (takes all of 2 minutes, and half that is getting the rosebud on the torch handle).

    Your stump jumper was trashed, so why not cut it off?  You could've popped the friction fit of the tapered splines using an angle grinder and cutting the hub along the side parallel to the output shaft of the gear box.  You own an angle grinder, right?

    I had to replace the gear box on a 5' Bush Hog.  I went to a buddies house for an extra set of hands,  and between the two of us and the torch had the whole job done in 10 minutes.  No damage done to the stump jumper or the castle nut.

  5. Side note – Never, ever – ever- ever chain to your tractor above the drawbar the way you did. Nobody thinks THEY will flip over backwards – yet every year, people die from flipping over backwards. Even more dangerous without a rops.

  6. Best video ever…I'm on day 2 myself – i haven't tried dragging it around yet but i might just for fun….ha.

  7. When you cracked your stump pan, did the shear pin shear? Were you using the manufacturer's recommended hardness shear pin? My dad, who thinks he is wise and knows all (actually, he's more of a "know-it-all"), kept breaking shear pins and decided to get a really hard bolt. Soon, he struck a large rock and BAM! He bent the driveline and a universal joint and just about destroyed the gear box. Luckily, we don't think he damaged the tractor or its PTO, but even so, the cost to repair the damage to the brush cutter was going to be more than we paid for the thing. The School of Hard Knocks has a very high tuition. I prefer that someone else pay it and let their experience teach me.

  8. Always leave the nut on the end of the bolt. That way you are hitting the nut and not damaging the threads. Plus when it does come loose it will not go flying. Be careful with the heat. There is a seal on the shaft at the gearbox. If it gets to hot you will have a leak. Then you can destroy the gearbox. Anti seize gease is a good option when putting everything back together.

  9. It is a tapered shaft to break the taper pulling evenly from both sides is the text book method. Never never hit a threaded shaft with out the nut on it to protect the treads. Be very careful heating hardened shafts not to apply heat to the shaft. Once it turns even dull red you ruined the temper. Apply heat to the female part only.

  10. Have you ever thought about heating up your nut and or bolt assembly? Heat expands it doesn't contract, until it cools

  11. Mistakes made. NEVER take the CASTLE nut all the way off. They cost 4 or 5 bucks, at best. Loosen the castle nut and beat the shit out of it. NEVER hit bare threads, I don't care how good you are with a FREAKING SAWMILL? Really? The drive Spindle is MUCH more expensive. Check your gear oil seals now, I bet they leak. NEVER use lube on threads. Use ANTI SEIZE. Using some long hardened punches, two of them, on exactly opposite sides of the spindle and the Stump Hump fitting, (granted this take two people to do) strike BOTH punches at the exact same time with identical hammers. Same size and weight, and try to use the same force on both punches at the same instant. That causes a harmonic vibration the will break ANY nut or spindle off (as long as they are NOT rusted). Heat melts your grease seals. Dropping it from the lift only means that now you will need to straighten or replace the 3 point attachment ams. God help the guy who buys this off of Craigs List. Grind the welds down and TRY to get the hump back into balance, Bent is ok, out of balance is not. I just watched a little more of the video. Nice gear oil stream. I told it would leak. I really should watch the entire video before commenting. The reason there is a hole in the center of the spindle is for a Bearing or Hub puller. that centers the puller so it doesn't fuck up the threads. FYI. Heat is the LAST thing to try. Best laugh I have had in a while, thanks.

  12. The problem with using heat on that bolt is that you are damaging the metal and where it will be brittle and have to be replaced. I saw the part where you dragged the bush hog around isn't a good idea either. That is a very good way to damage the entire unit and that particular bush hog is cheaply built with the thin metal it is built with.

  13. I am glad that you included what did not work, many would have simply not presented the methods that did not work.

  14. All that work and didn't sharpen the blades? Anyway, use the wedges to put pressure on the stump bump plate, use a little heat, and tap the shaft using a block of oak to protect it. Also, if you do your maintenance regularly, things come apart much more easily. Use anti-seize on your shaft (the crown bolt and cotter pin will keep it tight. Or get some goats…

    Just sayin' ……

  15. Watching this made me realize how fortunate I was having my grand daddy & old 65-70 yr old millrights I use to work with show me and teach me wisdom of having to work and mechanic in oil field and work at papermills my whole life that I listened and maybe wise enough to pass on to some of these millennials that once upon a time a mechanic knew every trick to working with metal & broke stuff and made a living doing so..

  16. Even the torch failed for me. Last ditch effort – I replaced the castle nut upside down and flush with the top of the shaft. Then I took a 10 pound sledge and hit it with great force to shock it. At the same time I had a 4×4 wedge already adding upward pressure. It budged.

  17. *CRINGE*… Those holes are NOT meant for you to pull it off from. They're meant to have a round bar inserted into so that the blades have a "stop" to push against while you take the nut off that attaches them to the hub. Pulling the hub off with those holes, while it is already cracked, is just going to make your life more difficult. Most likely by pinching the hub even more on the shaft as you try to pull it off, thereby gouging the shaft as you pull.

    To do it right, use a bearing puller with two arms. That way, it pulls evenly with the force always perfectly balanced and parallel to the shaft.

  18. LOL WHAT THE HELL KIND OFRED NECK ARE YOU .? Gotta be city boy gone country ? Next time watch YouTube videos instead of making them

  19. I needed to remove the outboard stump jumper plate from my Bush Hog 278 so that I could replace the oil seal.  As with everyone else, the plate would not budge after I removed the castle nut.  After watching this video, and others like it, I decided to take my tractor to a neighbor that is older, wiser and more experienced so that he could teach me how to do this right.  He had the job done in less than 10 minutes, and never broke a sweat.  Here’s now he did it:

    I took the shredder to him connected to the three point hitch of my tractor.  First he connected an electric winch to the tail wheels “axle” of the shredder, and then had me disconnect the top link and PTO shaft.  The winch was secured to a heavy workshop beam above.  Then he raised the back of the shredder to almost vertical, pivoting it up on the bottom links of the three point hitch.  This made the stump jumper plate convenient to work on.  Brilliant. Took one minute.

    Then he put a appropriately thick wood block and a stout metal splitting wedge under opposite sides of the stump jumper, at the positions of the internal bracing of the plate.  Then he positioned the castle nut flush with the end of the spline shaft so that there was about an inch of clearance between the plate and the nut, so that the plate would not fall off when the spline let it go.  Then he hit each wedge a few times, alternating back and forth between the two, and within a minute the plate popped loose.  Amazingly simple, easy and completely stress free.  Now I know, and perhaps someone else will too.

  20. Next time use a 1” ID machine thread nut (like off of a 2” receiver hitch with a 1” shank). Screw it down just almost level. Then, use a low profile jack to do your prying on the stump jumper while you hit the shaft with a sledge hammer. You won’t bugger your threads that way. Each hit add a little more pressure with the jack.

  21. I hate to tell you this, but did you notice the dimple in the center of the shaft? That is there to accept the point of an automotive type wheel/gear puller. The two holes in the stump bump are where the arms of the puller go.

  22. Glad you got it off,
    I always coat the stump jumper shaft with never seize when I reinstall,
    Once I had the bolts that hold the gearbox to cutter frame come loose so I had to remove stump jumper to get to them and tighten
    I removed the nuts and applied thread locker to those nuts before reinstalling

    I always look under the cutter and check that stump jumper nut to be sure it’s in place and the carter key is in place,
    Friend of mine, the stump jumper came off while he was cutting with the machine, but he was lucky it just when to ground and stayed under cutter,

  23. That 2" hole behind the gearbox is so you can drop a crow-bar down through and tap it off while it hangs on the 3pt hitch. Read the manual for a Bush Hog 306, and that's what it will tell you the same thing.

  24. All I can say is thank you for sharing this video it saved me on all the trouble you went through

  25. Keep in mind Men, many many men never had knowledgeable dads or granddads about fixing things so it's great to get help from videos. Not to mention not even having any male role model growing up.

  26. 30 yrs in the elevator business…my mechanics faced similar problems. You will not believe what they used as a penetrating oil. SLOAN’S LINIMENT…that was their go-to solution to stubborn nuts on frozen tapered shafts. The Sloan’s is expensive. My drug store special orders it for about. $16.00 for about 6 oz.

  27. My no brand red brush hog's castle nut and nut on blades were standard righty tighty lefty loosely. Fyi to anyone.

  28. OMG… tying it to the car… dragging it around the yard…

    when all you really needed was just a bigger hammer…


  29. Next you will post a video about how you now have a leaking gear box…since you cooked the rubber on the gear box seal?

  30. I hesitate to bring this up dude…but it is amazing that you did not injure yourself big time. Without proper shop practices, you are dangerous as hell. Glad you were not crippled though.

  31. Enjoyed the video but I won’t comment on the tactics however,
    very interesting. Here is another way to remove the stump jumper without heat risking
    damage to the gearbox seal. The alternative is to use a gear puller. This can
    be accomplished by drilling two holes in the stump jumper approximately 1½” in
    diameter just outside the center hub. This allows the hooks of the puller to
    grab as close to the center as possible. The gearbox shaft has a “center” location
    drilled during manufacturing that can also be used for the puller. Apply
    pressure on the puller as needed and occasionally striking the puller hex nut with
    a heavy hammer. Use plenty of penetrating fluid and when re assembling use
    anti-seize. This works best if the brush hog is upside down.

  32. You're a reckless idiot. I'm surprised you havent lost a limb yet! Seriously, the heaviest hammer you have is for hardwood floors?! You're an idiot and next time do your self a favor and call a professional out before you hurt your damn self!

  33. I love it when YouTubers use tools incorrectly in their intros. Saves me some time by letting me know I can skip to the next video immediately.

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