Didn't know there was an "A" variant.... wouldn't expect a great deal of difference, and I suspect the freewheel body is the M475-type that's found on a stack of hubs.
It won't be 142 x 12, 'cos M525 predates that.... It's just a Deore 6-bolt 135 x 10 Q/R that they haven't killed off 'cos they still keep a couple of 6-bolters in the lineup (M756 old XT is the other).
To remove the axle you have to unscrew the locknut, spacers if present, and the bearing cone to pull the axle out.
It should be noted that you remove the locknut & cone from the non-drive side of the hub. The cone on the drive side is recessed below the rim of the freewheel body thread, so you won't get your spanner onto it. Even if you don't need to for access, you should remove the brake rotor in order to avoid getting grease on it. Add a T25 Torx key to the previous tool list.
My tip is to get the locknuts moderately tight on the cones with the bearing ever so slightly loose, then finely adjust by only tightening the locknuts against each other. This tends to also rotate the cones slightly and properly preload the bearing, and the nuts are already tight and can be easily fully tightened without rotating the cones anymore.
I have a slightly different method. First, before reinserting the axle, ensure the locknut & cone on the drive end are nice & tight together. Screw on the off-side cone, and
slightly overtighten it on the bearings; you should still be able to spin the axle, but with some drag. Fit any spacers (there's usually at least one) and the locknut, and while holding the other end of the axle, tighten it finger tight against the cone. Now with your 15 & 17mm spanners, tighten the cone & locknut against each other. By some quirk of differential friction, the cone will loosen from the bearings as it snugs up on the locknut. With just the right amount of initial preload, you'll end up with a perfectly tensioned hub.
