That's good info, thanks. Bending the leaf switches fully restored the spring in the stick. While I had it all disassembled, I noticed the pivot bracket was not turning on the pin; the whole pin was turning. The pin was frozen inside the bronze bushings. I removed the pin (with some difficulty; had to press it out in the vise) and it was coated in some black sticky gunk. I cleaned and polished the pin, and cleaned inside the bushings. I put it all back together and the pivot bracket now turns easily on the pin. The joystick now works like new!
And I didn't have to replace any parts. Just a little bending and cleaning.