old school locking hubs

[1969 GMC]

OK, the other day I got the GMC stuck in a friend's yard but the front axle wouldn't engage. The hubs seemed to not lock. They are the old style, according to the pic Rod sent me are found on 65-69 3/4 ton 4x4's, they don't have a plastic dial. Anywho, today I tore 'em apart and cleaned the pieces inside. They seemed to be in OK condition. I did the drivers side first, and when I was done it worked superbly, it made an audible click when locked. The passenger side I was worried about, it was covered with grease and wouldn't lock at all, would just spin. So to my surprise when I pulled it apart and washed it in mineral spirits and got the grease off, it is an almost brand new hub. The whole thing. Still shiny in places. Well, I cleaned it off and regreased it, then reassembled the hub. Problem: the hub is VERY hard to lock. I can't do it with my hand, neither can my dad. We can with a pair of pliers, but it leaves marks in the cast aluminum and I don't like to do it that way. It doesn't make a click like the drivers side. We took it apart again and looked, it is just fine. No breakage, and if you compress the springs with your hand it locks/unlocks just fine. My dad suggested that it might need to be sanded or ground somewhere to allow clearance. Is he right? This really pisses me off. Sorry this post is so long.