Good posts and the correct diagnosis of the noise. Is the blade break clutch pad still if good shape? It not you might have been better off with a full blade break clutch replacement, but that clutch assembly runs about $175 for the part now days. To work on the clutch I’d recommend removing the whole clutch assembly, replace the bearing and reinstall. Do you have a copy of Technical Manual TM1471? I believe you can still find it online for free in PDF format with a Google search hosted on a website called Bionic Engineering. That manual is the dealer repair manual on the silver deck mowers but since the JX75 is identical except for color of the deck if yours has the Kawasaki FC150V engine.
Both pads are in good shape. I've never seen a clutch pad before, and for all I know, these pads could be worn, but they look good, round with no pieces missing, and look like they should last a while.
I looked at that pdf, and the clutch in the pdf doesn't look like mine. No matter. I have the whole clutch off now, and I'm comfortable putting it all back together. I couldn't come up with a way to get the bearing off the inner (upper) half of the clutch, so I'm cutting the old bearing into pieces where it is. My Dremel seems to be incredibly slow (using diamond coated bits). I will have the steel balls out of the bearing tomorrow morning, and will just have to see what happens. Will probably need to find a way to cut metal faster, for the sake of my sanity. Not something I do very often, so have a cheapo Dremel. Doesn't seem to cut anything, at times.
Engine is a Kawasaki, but haven't given a thought to it, as the noise of the bearings drove all other thoughts from mind. Mower is a 1999, if that helps.