I own a Craftsman push mower, model 917.371812. When I first purchased this mower, it would pull backwards easily when I trimmed around trees. Now, when I try to pull the mower back, the rear wheels lock up. This makes trimming very difficult. Any assistance you can give will be helpful.
I would suggest disassembling the drive system (except the transmission itself.) If it's rusty, clean the rust off with sandpaper. Then lubricate the drive system and re-assemble it. I recently did this to a Husqvarna mower that was hard to push. It is now almost as easy to push as a regular push mower! An exploded parts diagram can help you disassemble and reassemble the drive system correctly.
