I answered your other thread. So you didn’t need to make 2. Just for future reference pard.

But I neglected to answer about removing the factory Brake. I believe on that style of brake, there are Flats on the sides for an open Box wrench. A large one! Don’t know exactly, but it’s probably like 1-1/4” wrench maybe? Anyway, just measure the diameter of the flats. You have a Vernier Calipers? Once you know what to look for, you should see the Flats immediately. Either on the sides or top & bottom.