Replacing Ignition Switch in 73 Duster

Hey all,

I'm trying to change the ignition switch in my 73 Duster, because it won't start. I know the relay, solenoid, starter, and NSS are all fine. So it's basically the ignition switch or something in the wiring. Now, I have pretty much everything off up to the ignition switch. The only thing left on the steering shaft is the lock plate. I have a lock plate depressor, but it doesn't work. The thing will not budge backwards no matter what kind of pressure I apply with the tool. How am I supposed to get this thing off? Has anyone ever done it before?