Getting a stump knocker off a MX6

mopar440cu · Jul 11, 2016

Can somebody please tell me how to get the stump knocker off my MX-6 bushhog. It is leaking and I would like to replace it but, I cant find info on the subject and my MX-6 manual doeskin really tell you.

I am thinking that it is pressed on and I'm trying to figure out how to get it off, then put it back on.

Any help on the matter would be gratefully appreciated! :thumbsup:

beenthere · Jul 11, 2016

:welcome: to TBN

May be the center bolt holding the pan to the drive spindle.

OMW49246: MX5, MX6 and MX7 Rotary Cutters table of contents

mopar440cu · Jul 11, 2016

Thanks but, how t get it off? Maybe with a nut and bolt combo behind the stump knocker? Then how the heck would ya press it back on?

beenthere · Jul 11, 2016

My manual for my 513 rotary cutter shows using a puller (your nut/bolt combo? ) to get it off.. but suspect just tightening the nut is sufficient to get it back on.

jd110 · Jul 11, 2016

The "stump knocker" is on a tapered spline. It goes on very easily just by aligning the splines and tightening the bolt to spec. Coming off can be tricky. Recommended procedure is to remove the blades and then remove the center bolt. Then stick a heavy piece of pipe through access hole in deck that is long enough to hit with heavy sledge. Place the pipe on heavy part of stump jumper where the blade attaches and hit with sledge hammer until it comes off. The tapered spline will fall right off as soon as it breaks loose. When reinstalling, tighten center bolt to 450 ft lbs if it uses a lock washer and 580 ft lbs if it has a flat washer only.

topbuilder · Jul 12, 2016

Pounding from the top has never worked for me. I use a heavy duty puller (bolted into blade holes) from the bottom and a lot of heat. Then apply a BFH to end of puller while under extreme tension. If you get it off, make sure to use anti-seize lube when reassembling.

brown40 · Jul 12, 2016

Mine busted in half, leaving the spline in the jumper, and nothing short of cutting torches, and blasting it with a sledge broke it loose. I don't know that I wouldn't put some grease in it and see how that fared for leakage. Maybe add a couple washers when you bolt it back and see if it begins to work down during the lube testing. There's a huge range of acceptable gear lube viscosities, but JD goes pretty thin when they fill it.

Xfaxman · Jul 12, 2016

mopar440cu said:
Can somebody please tell me how to get the stump knocker off my MX-6 bushhog. It is leaking and I would like to replace it but, I cant find info on the subject and my MX-6 manual doeskin really tell you. I am thinking that it is pressed on and I'm trying to figure out how to get it off, then put it back on. Any help on the matter would be gratefully appreciated! :thumbsup:

brown40 said:
Mine busted in half, leaving the spline in the jumper, and nothing short of cutting torches, and blasting it with a sledge broke it loose. I don't know that I wouldn't put some grease in it and see how that fared for leakage. -------------------------

The grease in the gear box thread: http://www.tractorbynet.com/forums/attachments/271324-grease-rotary-cutter-gear-box.html

mopar440cu · Jul 19, 2016

I just got the chance to read all your responses, due to surgery. I really appreciate the advise!!!

RedNeckRacin · Jul 19, 2016

My Mx10 is held on a tapered spline. There is a castle nut and a cotter pin. I believe thr nut is almost 2" and is extremely tight. I used a 3/4" ratchet to knock the nut loose and I coobled together my truck jack and some chain to make a puller. I looped the chain up over the bar that holds the blades on each side to make a cradle. Then I set the jack in the cradle and jacked against the spindle with the nut on it so I didn't damage the threads. I then ran the jack up with alot of pressure and had to hit the stump jumper pan with a BFH and a piece of pipe through the vent hole in the top. It came apart with quite a racket with some persuasion.