I removed the small bolts holding the brake pedals on the rudder pedals. I then installed a long bolt all the way through the brake pedal. As others have before, I used A3-60A bolts and a number of washers at the end. (The bolts are $11 each... but I'm thinking of replacing them with the correct length - 1 washer.) Also, I ordered bolts that aren't drilled. (I'd feel better with locking nuts - cotter pins)
I also added the springs onto the brake cylinders as a number of builders have done. Odered from McMaster-Carr 1 Pk 6389K625 nylon bearing flangs - pack of 5 ($2.41) 1 Pk 9657K115 Steel Compression springs - 12 pack ($6.23) 4 E 9946K13 Aluminum set screw shaft collars ($1.99ea)
