Do you have access to a bolstered type screwdriver, the type that has a hex at the bottom of the handle on the shaft? You might be able to get more torque on the bolt with that type driver. Another solution would be to use a manual type impact driver if it's really stuck bad. Something to watch for-sometimes the pin will break when they are put together at the factory. Usually they do that below the threads, so you can fish the end out with a small magnet.
