I've got an Ariens 36" power brush, where they took their standard snowblower "frame", mounted a slightly more powerful motor on it, and then attached a brush to the front instead of a snowblower. Today's problem with it is that the two bolts holding the brush to the frame aren't strong enough. They used 3/8" bolts, with some captured nuts to keep them attached, and with the extra weight and vibration of the brush, the bolts work free, ovalling out the holes, as well as causing the pto belts to the brush to get stretched out. Finally, trying to get the bolts tight enough to hold, the captured nuts got stripped.
Here's pics of the existing captured nuts. While it's adequate for a snowblower attachment, it just isn't enough for the brush attachment... They only overlap the hole they mount in about 1/8" in one direction and not at all in the other direction.
Rather than flushing more good money after bad and buying new bits from Ariens, I decided to make a beefier setup using 12mm flanged nuts and bolts and fabbed up a bracket to hold the nuts in place (as they are difficult to access when the unit is assembled) instead.
This pic shows the difference between the original and new setup:
Forgot to take a pic of the setup I made for holding the nut in place. It's a short length of .25" x 1.25" flat steel, drilled a 18mm hole (same as the wrench size for the nut), then abused a deburring tool in a air die grinder to gouge out the 6 points so the nut would fit into it and be prevented from rotating, but could move a little bit, then welded that to a strip of 3/16" x 1.25" flat steel that is bolted to the frame of the brush head. 3/16" is slightly thicker than the flange on the nut, so when the assembly is bolted to the frame, the nut is held roughly in place and can't fall out, but it can move slightly. Then drilled out the corresponding holes in the drive unit frame (didn't have to remove much, as they were ovalled from the old setup, mated the two units together, installed the bolts and done.
I don't think I'll have a problem with this setup.