Originally Posted by
xlbs
You could use a length of pipe the right diameter just to slide over the end of your wrench handle. This has been my favorite "cheater" for years. Some hardware stores sell short lengths of pipe to make pipe clamps cheaply so you won't have to lay out lots of cash.
It also may help to remove the pedal and put another cheater pipe over the crank arm. Have an assistant hold the crank steady with that cheater pipe while you work on the bolt with yours.