I had a loose gearbox on my Brown Series 400, Model 472 Rotary Cutter. Bought it new in 1999 for $2000. Never had any problems until I saw the bolts were loose and it was vibrating the other day. I watched a few videos (including yours) and finally got the courage to work on it with the help of my wife. We managed to turn this 1050 lb cutter upside down. Removed the cotter-pin from the Castle Nut that held the stump jumper on. The stump jumper was still in very good shape after 20+years. Loosened the castle nut until it was flush with the end of the bolt. We then wrapped a 6ft piece of heavy duty chain around each blade where they mounted to the stump jumper, then placed a 20T Bottle Jack (had a 4T, but wanted the extra "umph") on top of the castle nut and put the neck of the bottle jack under the chain. Then slowly pumped the jack. Immediately saw the stump jumper start to move just a tad, then it POPPED with a big "bong" sound which told us the stump jumper had broke free. We removed the castle nut and repositioned the bottle jack to lift the stump jumper up about 1.5 inches, then we just lifted the stump jumper off with my Boom Pole and a chain. We then stood the bush hog on its side with the boom pole and chained it to a tree to keep it from moving. Then we removed the old gearbox nuts off of the 4 mounting bolts and replaced them with new bolts, nuts and washers. Also new lock nuts. Then laid it back on the ground upside down, reinstalled the stump jumper, castle nut and new cotter pin. Then sharpened the blades and flipped it back over and it was ready to go back in service. The toughest part was taking off those original 4 mounting bolts/nuts. They were dang near seized up after 21 years. I put some anti seizing lubricant on the new bolt threads. Couldn't have done it without the wife's participation.

Excellent vid thx

Fairly new to brush hogging... any tips on how to get rid of a field of spikes (small tree stumps) after brush hogging?

You state the hydraulic jack has the option for three legs. I see that the two legs you use are 180 degrees and opposite from one another. I see what appears to be a spot for the third leg on the coller. The jacks currently listed on the HF webpage have the jaws 120 apart. I don't think these would work as the pull would be uneven.

Don't have to cut mine because it snapped off, it happens when you let someone use it and they think they can set it down on small boulders, anyway this seems like a good idea and I was wondering if you needed to heat it up a bit and why couldn't you pull it all the way off with the hydraulic puller? Thanks for uploading this.