Outdoor Power Equipment and Small Engines - Snapper rear engine rider

Does anyone know where I might find a repair manual for a model - 281223BVE. The problem I'm having is when its in reverse and the brakes are applied, it make a noise and you can feel the whole mower "jump". I've got a parts breakdown on CD and it shows a brake drum and a brake band. Could it be anything to do with these? I'm fixing to go into the mower and just wanted to know, what to look out for? It will occasionally do this in foward too.

I know of no online service manuals for Snapper, perhaps someone else will but as far as the brakes go, I'd say, just as your automobiles drum brakes will grab and jump with a cracked brake shoe, so to will this brake setup.

This should have the brake band around a drum like a go-kart type brake, but it also should have a brake shoe that goes into the driven hub on the rear end. This works smoothly in forward even when it's worn down, but if it's worn enough to create a severe angle of attack on the braking surface, it will dig in and bind, jump, and make chattering and/or scraping noises.