Swap out the spring in your Sanwa JLF or JLFD joystick when you want a firmer feel.
To install these springs you flip your stick over so that you’re looking at the underside.
Now carefully prise the c-clip off with a flat bladed screwdriver. Keep a finger on it, there’s a good chance it will fly off and disappear never to be found again! Also note, when you remove the c-clip the shaft of the joystick will want to fall down and out, so somehow keep hold of that too.
Remove the actuator, and you’ll find the spring underneath.
Pull it out, swap it with this new spring, re-install the actuator and push down to reveal the groove, then install the c-clip.
And you’re done! Give your stick a try and see how it feels.