Replaced the same brake unit on this machine, on 01/29/2000 and since the transmission was easily counted as it spun around, I figured it was binding on the brake unit, slowing it down. Since I don't own the tool, I've had to rely on an extra fender washer between the pulley and brake to compensate for the added 1/4 degree turn. After I put it all back together, and made sure to put the key lock washer in place at a 1/2 inch from the pulley nut (watch Youtube for this), it was fine. Belts were in good shape too.
I tipped the machine over this time, instead of doing it all from underneath, and found that inside the back panel, (remove the 2 inner, not outer screws) there is an anti-tip switch in the center, that needs to be pushed down to reset the machine. Everything worked right after, and clothes are now mostly dry again.