"Take the brake assembly apart (remember how it goes back together. Clean the two plastic pins, lube the metal casting, buy a new brake pad, and reassemble it. Oil it greatly, and make sure when you push the brake pedal that the lever on the brake assembly moves forward and back. that lever has two bent areas that push the little round pins in and in turn, they push the brake pad in to make contact with the brake disc! Most any lawn tractor repair place will have brake parts. Note: There might be a small steel plate inside the assembly, that goes in on top of the brake pad/ block. the brake operating rod should have an adjustment on it, too.
Don't worry about getting oil on the brake pad, or anything else. It will keep it operating well. Been fixing lawn tractors for about 20 years."
Rusty, no plastic parts and cannot find someone who has the brake puck. I put it back together and adjusted it. Works but probably I need to install a go cart brake. Thanks Larry