The #10 torflex, 2.5K to 4K, AKA 3.5 K
axle uses 10"
brakes. The #9 torflex 1K to 2.2K uses 7" brakes. The spindles are different sizes so the drums would be the issue. The brakes both use a 4 bolt brake backer plate but I'm not sure if the spacing is the same. I assume you are using the #9 on the
Boler. The #9 has smaller spindles. You could use the 10" brakes on a 2.5K #10
axle if that is what you want order.
Eddie