If you have the newer style Brake Buddy, call Tech Support and see if they have one of the old style clamps they could send to you. When I sent them my old original Brake Buddy on their trade in program, they sent me a new unit for $495.00. At that time tech support told me to keep my old brake pedal clamp when I shipped them my old unit. They said that most people preferred it to the new style.
When I got the new unit I thought, why not use the new clamp. My toad has the same problem as yours, the new clamp could slip off, the old style I kept worked perfect. They probably have them laying around due to their ongoing trade in program.
2005 Safari Cheetah 38PDQ - 2009 Ford Flex
Me (Gatogonow), The Boss (DW), Honey Bunny, Maggie May and Mollie Kay (The Gatos)!