How to Install Brush Cutter Blades

It seems like I've talked all summer about brush hog blades, but I get TONS of questions about them that this video series will help answer. Today the topic is how to install brush hog blades.
You might be wondering why a video like that is needed and be surprised at how many questions I get on this channel, and how many calls come in to an equipment dealership from customers who have installed the blades wrong on their brush cutter. It's not that hard to do.
First, if there's not much uplift on the blades, in other words, they're fairly flat, it's possible to install them upside down. I had a recent inquiry by a viewer who was experiencing one side of the brush hog cutting higher than the other. Turns out he had installed one set of blades on one stump jumper upside down. It made about a 3" difference in the cutting height from left to right.
Second, it's possible to install the blades so they're going backwards, and they won't cut very good with the dull side leading the way. We checked the blade rotation on this cutter before installing. Most cutters have decals on the deck that show you which way the blades travel and you want the sharp side going with the arrow, but I don't trust that. If the flunkie at the factory was a little disgruntled, he could switch the decals and cause much mayhem later on. So I prefer to check them with the owner's manual, where there'll be a diagram showing blade direction.
The only other tricky thing is getting the little key on the blade bolts into the slot while pushing up and holding a heavy blade. It's not that hard, but it does require a little effort, and, as I mention in the video, having a big piece of clean cardboard on the floor makes it a lot more pleasant. Also, ALWAYS PUT JACK STANDS UNDER THE EQUIPMENT...DO NOT RELY ON TRACTOR HYDRAULICS TO KEEP THE CUTTER IN THE AIR!!! I've known a couple of people that were crushed working on equipment (or cars) and that's not a good way to go.
A couple of final thoughts that we covered in the video. It will help your dealer out greatly if you shoot a picture of your serial number plate with your cell phone when you're getting ready to go get parts. There were two different blade designs offered on this model cutter and having the serial number insured I received the right set. If you bought the machine from the dealer you're buying parts from they'll likely have that number in their computer, but it speeds everything up when you can just show it to them. Secondly, while you have the big sockets out to tighten the blades, go ahead and check the torque on the gearboxes. That's something a lot of people forget to do because they're big bolts and you'd think they'd never work loose, but there is so much vibration on a cutter that it can happen. In the video, there was one bolt that had worked out enough I put at least a half turn on it. Once those bolts get loose you have a recipe for an ugly and costly failure.
Last thing to do is to tighten the bolts, which on this machine, require 600 ft. lbs of torque. There's no way I have anything able to do that, we got in the ballpark by Chris tightening them as much as he could with his 1/2" impact. To those of you who want everything exact, feel free to yell at me. In a situation like this where it's going to cost me a lot of money to get a torque multiplier to get the exact torque numbers I'm going to say Chris's impact wrench is going to be, "good enough for who it's for."
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[@jameslovelace7773]

I just bought my first tractor to maintain my new 5 acre property I bought in rural North-West Florida. It is a 2019 TYM T394 with 117 hrs. It came with a front bucket, a 5 ft bush hog, and a tiller. I have had lots of questions and find your videos very informative. Thank you for educating us newbies.

[@TractorMike]

James, glad to do it, thanks for watching!

[@billfischer6464]

Just wanted to say thanks for making these videos and putting info out there for people. I've been around tractors and equipment my whole life, but nobody knows everything and refresher are always good. Think the work and time you put forth for us whether young or old new to it or experienced it's of value to us all. So a huge thanks. 👍👍

[@Just_Chuck_It]

I keep 2 sets of blades. 1 set I keep sharpened like lawn mower blades. And the 2nd set are just regular brush blades. I usually keep the lawn blades on for regular lawn maintenance, but 2 times a year I usually throw the brush blades on and knock down the brush that likes to creep in. The first time I did the blade swap it took be about 4 hours if frustration, foul language, and progressively larger hammers. Once I got the blades off, the same was true for reinstallation. 😂 But now after about 6 years and multiple swaps I have a system. I can pop the blades off and pop the 2nd set on in about about 45 minutes to an hour depending on how everything cooperates. When the brush blades go on, I use that opportunity to sharpen/touch up the "lawn" blades. It's amazing how well the grass can be cut with a rotary cutter that has sharpened blades. Keep tractoring.

[@cainefarnum8972]

Mike found all you video's on brush mowers helpful when getting and old 1965 Massey Ferguson mower ready for the summer cutting

[@semco72057]

I need to get the blades sharpened on my bush hog right now and the last two times they was sharpened it was while the blades was on the unit. This time I want to take the blades off and do it right. Thanks for showing us this video and it will help those like myself who is not familiar with removing the blades, but know how to sharpen them.

[@mitchs323]

After working for the Div of Highways for 35 years, I've changed my share of brush hog blades. I've come on all the problems you described. Or blade bolts used a roll pin and castle nut to retain the blades. I've had to burn off the bolt heads, use a 16 lb sledge hammer to get them out and in a couple of instances, had to replace the blade bar to change blades. We torqued ours like was shown in the video, only using a 3/4" impact. we never sharpened blades because they ran into so much debris and rocks, they weren't in good enough shape to sharpen. We had 6 mowers at one time, so during the summer we would change blades often, sometimes 2 or 3 times a week. Retired now and I don't miss it a bit, but sure do miss the people I worked with.

[@robertfakler8564]

Now I know I can't do this myself. Thanks Mike.

[@sofakinggood5829]

Awesome detail and right on time. Thanks

[@dwayneloftice2326]

I remember that task with my old Southeast 10' brush hog. Blades were HEAVYYYYY!!!!

[@_AndromedaGalaxy_]

damn! 10'! thats huge!

[@GrampiesWorkshop]

Thanks for posting!!!!

[@donnykiofetzis5775]

do you know that if you put anti seize on the treads and you torque them down to 600lb . you will have a faults reading it will be more around 980 lb. i see this to many times people snap bolt that have been lubricated then torque down. torque specification require " torque dry bolts and nut "

[@OneAmercia]

If you do it by your self use a hydrophilic jack underneath to hold the pin and blade up and then go to the top and you are all set up to tighten the nut on top. IMI ( important minor information)

[@williampockoski5029]

Great video, thanks

[@timothyczapranski8254]

You can do it yourself - I do mine. I use place a hydraulic bottle jack under the cutter with me, Once I get the blade up up and the pin started I but the bottle jack under the pin and start raising the jack against the head of the pin and it pushes the pin all the way up and in. Easier with two guys but if your alone then use the bottle jack method to push and seat your pin.

[@robertlambert4881]

Didn’t realize that there was a slot on the pan to lock that nut on so you could tighten it without having to use a wrench to hold the the nut on the bottom ,apparently when I bought the brush hog the the slot in the pan was missing and the tightening just rounded the hole on the pan,anyway that video was very helpful,what were are going to do is use castle nuts with cotter key until comes a time I have to change the pan😊

[@bryantjones8039]

Thanks for the great video. I have a 5ft Land Pride bush hog. How tight do my blads need to be?

[@tlbfarm4473]

One man operation: easey peasey. Use the FEL to lift the bushhog on it's side, lean it up on something - and then work on it in your leisurely and comfortable standing up position!

[@donniehill4826]

now i know enough to know i can't do this....thanks for saving the pain....

[@je1279]

Could you use loctite on the gearbox and other housing bolts to prevent loosening?

[@jerrybeck8812]

Nice video, good info. I’ve always like your videos but I’m not saying I didn’t like the video on “how to sharpen a blade” a couple videos back, I was disappointed that sharpening a blade wasn’t shown... I gathered from it was you don’t need to sharpen them... just wanted to pass that along.

[@TractorMike]

That video created quite a bit of controversy, and I sure get what you're saying. I may do a follow-up later on where the sharpening is actually done, and probably with the blades left on the machine. I wanted to do that video with Jerry because he feels, like I do, that many homeowners worry too much about keeping rough-cut blades razor sharp. I would bet that a large percentage of my viewers will never use their cutters enough to have to sharpen them, just because they're mowing 20 acres of grass a year, maybe twice. If you're clearing land, or cutting a large area often, it's a different story. That video was made to answer the question "When should I sharpen my brush hog blades" which I get all the time. Most of the time my answer is "probably never", but I wanted to explain that and thought Jerry did an excellent job. Those blades we just installed on my 8' cutter will probably last until I'm pushing up daisies without me ever touching them again.

[@chrisjones9115]

Do you sharpen your Bush hog blades? Why or why not? Never mind. I found your video on sharpening blades!👍🏻

[@patgreenwell1881]

I took my blades off from the bottom of a ath 600 bush hog finishing mower, and sharpened them, and put back on, I didn't torque anything and I didn't do it from the top, sounds like I did this wrong, do I need to go back and fix something? Also, when running it sounds real loud, could the bearings be bad? do you have a video on changing bearings?

[@triciahill216]

Mike - Would it be okay to tilt the mower up on end or side with a front end loader to change the blades?

[@denisewildfortune4058]

Hey Mike, was Chris using a torque Stick on the end of his impact wrench or did he have a calibrated impact wrench to achieve 600 lbft?

[@TractorMike]

He just tightened it as tight as he could with the air tools. It's not exact and that kind of bothers me, but the truth be known. if I took it to a dealership, they'd probably do the same thing. Manually getting the torque just right is a whole lot more expensive than just holding the impact on it until you're sure its really tight. We had no way to test it without a significant investment in tools that I'm not willing to make. If a blade comes loose at some point I'll know it was a bad idea.

[@jimg8218]

Use floor jack to help hold pin up while put nut on

[@leedawson8301]

I see me with a ratchet strap strung along like a spider web holding up those blades. I also see me with a half inch drive breaker bar, a three foot pipe extension breaking those nuts loose. Happy happy happy

[@aaluck]

Thanks for the great video as usual. Your video gave me the confidence to do this on my own. Now the problem...I’ve been hammering on these bolts for an hour each. Any additional ideas on getting them out. Thanks again

[@TractorMike]

penetrating oil, heat, and elbow grease... unless you have access to air tools which will take those suckers right off! Hope it helps!

[@aaluck]

@@TractorMike Thank you, Mike. LOVE your channel...watched 4 videos this morning. However the nuts are off with a 3/4 air impact (which I learned from your video). That took about 2 minutes....The problem is the bolts/pins, still holding the blades on. My son and I have beat on these for literally an hour each. I will try heat.

[@vivamya]

I raise the mower, put steel plates on edge between the blade and floor, and lower housing onto the plates. One or two wacks with a Hammer and brass drift pops em right out. Why does nobody address the keyway alignment on the shaft? Looks like a "feel" thing?

[@larryrivers2752]

I change blades by myself, difficult job! Mine have castle nuts so no torquing. Maby you could show everybody how it's done. I use a floor jack to hold the bolts in place.

[@jeffstrains4014]

I do the same, if I have a helper I have them finger tighten the nut with socket on it easy finger pinch if you accidentally let it move

[@dmorris5369]

I have a new 4 ft brush cutter. The tip of each blade has about 3/4” of play up and down. Is this normal?

[@johnsimms5915]

After replacing the blades, should there be any vertical movement of the new blades. I think the castle bolt only goes down so far, then you put in the carter key and there is still a little vertical movement of the new blades. Your thoughts?

[@TractorMike]

John, that's right, the blades pivot on the bolt They can move, you don't want a stump jumper that moves up and down, that's the sign of a problem coming.

[@josephboccio9940]

One thing I was looking for when putting the blades back on. I noticed they don’t tighten up tight to the bottom when the bolt is tightened. Are the blades supposed to still move around. I didn’t notice when I took them off. But they do move around when tight.

[@_AndromedaGalaxy_]

yes. they free swing.

[@BrucesShop]

OH my I hadn't subbed after all this time I am in.

[@tosborn56]

Why do my bolts spin? Did the keys get sheared off or worn off? Are there bolts without keys?

[@TractorMike]

Chris says either the key has rusted away or the key way on the stump jumper and bar is stripped and won't hold the key tight. You'll need to lift the machine and safely prop it up then have one person with big vice grips or a pipe wrench hold the bottom while another person tries to turn the bolt. If that doesn't work you're stuck with torching the bottom part of the bolt off and driving it out. Good luck!!!

[@lmfarms4611]

on my brush hog I get grass stuck between the pan and blade, then the blades won't move. How do I keep from getting grass stuck there?

[@KB4QAA]

Check your deck angle. Be sure the angle is correct to discharge the grass.

[@cherokeemapcrew]

Now I know the reason for that hole on the deck.

[@johndenny6025]

How about standing up with front end loader? Easier to work on.

[@stephensmithsbarsmustangra4]

Mike, I wish Chris was 573 repair. Lol

[@TractorMike]

He is very good and very much in demand here.

[@LarryTait1]

That made the whole process much less intimidating!

[@linganagoudapatil377]

Please send me how to make this cutter,

[@jasonsechrist1]

What size nut

[@TractorMike]

Apologies, I can't give you a specific answer on that one. The sizes vary from cutter to cutter. Should be in your owners manual!

[@taipeikartman]

Shitty design of these brush cutters endanger everyone when trying to change blades.