troy built bronco has blade belt keep coming off

I have a troybuilt bronco that had the blade belt keep coming off. I checked the belt pulleys and guides all apeered to be fine on the right side I noticed one of the pulleys was leaning the bracket holing it wasn not bent I took the pulley off and noticed the bolt wiggled in holeof bracket causing it to lean . hole is not hogged out.the shoulder on bolt was long enuff that when nut was tightened up bolt would lean with belt on. I put a wide washer kind of like a fender washer on bolt under bracket to give it better support I placed another washer top of bracket under belt guide piece that gave the whole assembly better support and made that pulley line up with drive pulley better belt stays on , and mower mows great now.