I removed all four grease fittings and soaked them overnight in brake cleaner. After verifying I could get grease through them, I reinstalled them. Sadly, it made no difference - none of them took grease. After reading all your suggestions I’m going to have my mechanic remove the kingpins. Is there any way to tell if my current ones are oversized before he removes them?

My dad always told me, "Don't force it, get a bigger hammer".