Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have an old well functioning Honda HR 215 mower.  One wheel is wobbly and need to be tightened.  However, I have not been successful in preventing the bolt on the  inside of the wheel from turning when I turn the bolt on the outside.  Any recommendations would be greatly appreciated.  The bolt on the inside appears to be just like a flat washer type bolt.  I have tries to get a wrench, screwdriver, and vicegrip inside to prevent turning, with no luck. 

Thanks, Jim