My boss wants to use his Trek 1100 (early 90's model) on a trainer. I'm tuning it up for him. The brakes work fine and hold well, not that he will need them on a trainer. The bracket cap is the little plastic bit that covers the top of the lever and the access to the cable end holder. Of course Shimano also calls the hoods "bracket covers" so there may be a more common name for that part.
Is this part just to keep dirt out of the brake lever housing?
It doesn't look like it affects the brake lever's performance, would it be okay to just epoxy the two pieces together?