I struggled with this too on one of my SC10 axles. The key is using a good set of pliers with a lot of leverage and grip. The pliers I had were not very good, but when I brought it to my track to have someone else have a crack at it, they made it look easy.
Here's an example of a good set of pliers:
http://www.amazon.com/Klein-D213-9NE...0005529&sr=1-4