Bush Hog Squealer 72 blade replacement

[marvinminor]

I'm trying to replace the blades on my bush hog brand model SQ 72. When I tighten the bolts that hold the blades to the pan the blades will not swing freely. Am I doing something wrong? I have new bolts, just like the old bolts. Do I need to leave the bolts loose? Looks to me like the blades would eventually fall off. These are genuine bush hog blades and bolts for this model. Also, do the blades spin counterclockwise?

 

[Imaybail]

The bolts have a swaged key that should index into a keyway in the blade holder. After a few blade changes, the keyway becomes worn and lets the bolt pinch the blade. The manual calls for tightening the nut to 600 ft/lbs. I can't get that value without it locking up the blades, so I just use locktite blue and back off until the blades swing free. I haven't had any problems with losing blades, but I usually have mine off two or three times each season for sharpening. Also, check and make sure the "stump jumper" pan is not bent and causing inteference with the blade travel.

 

[RickB]

Good advise above. Also, an old square back 72 will have the blade bar separate from the stump jumper. Make sure there is no debris between the bar and pan.

 

[marvinminor]

Thanks. I was trying to put the blades on upside down. I turned them over and everything worked fine. I had to get a new blade weldment because the old one was worn out. It came welded to the stumpjumper for this SQ 72 with later serial number. I also got new blades. The blades turn counterclockwise and that had me confused as to which way the sharp part of the blade was to point. I didn't have a torque wrench but I got them on as tight as humanly possible and I don't think they'll be coming off. Boy, it runs so quietly now. It was about to shake me to death with the worn out blade weldment.