I'm happy to help but of course Scott's the one that deserves all the praise. He was the only one helping me try to find the package of films that contained the Assault cpos when I was there. And as it happened, the Assault package was buried WAY in the back on the container. It really took a huge amount of work to get back there, and all kinds of pallets of stuff needed to be moved out the way. It took hours. I'm really happy that we didn't give up on finding them.
I rebuilt mine Darryl, and I know you could have done yours too. Rebuilding them isn't anything difficult per se, they are just tedious and time consuming. Heck, 12 screws and 8 bolts need to be removed just to detach the things from the panel.

But once out they are not too difficult. A good thing to do right off the bat is to cut the wires to the triggers and use a Molex for those connections. That will make taking the sticks out and replacing them a lot easier.
Anyway, if you feel like you're hitting something, inspect the cushion ring (black rubber ring) on the actuator (white plastic round piece near the bottom of the controller). It may have slipped out of position. Most often these just melt away over the years and turn into goo. There's a pinball rubber you can get that is a good replacement if you need a new one.
Here's a pic of an exploded diagram of the joystick for reference:
Assault stick.
For those that will be doing a rebuild, the one thing that's tricky is that when you are replacing the pin that goes through the pivot ball, you need to be careful not to slice through one/both of the wires for the trigger. The best advice I can give is just leave those wires out of the mix until AFTER you get the pivot ball and pin in place; then just feed them down the shaft.
When I rebuilt my sticks I used parts off 2 NOS Atari logo joysticks. They share many of the same parts as the Assault controllers (i.e. the upper/lower housings, actuator & ring, pivot ball, etc.). I definitely recommend replacing the upper housing when doing a rebuild along with the pivot ball and cushion ring of course. The area where the ball makes contact with the housing gets pretty worked over time. Having a new housing there along with a new ball makes for a really tight controller.
The red arrow below points to the upper housing:
Oh and definitely don't forget to lube with lithium grease as designated in the diagram.