Here's my old broken spring and how the spring looks on a new latch assembly. The push-button door lock knob spring (RH PN 9720760 and LH PN 9720761) is available from Classic Industries, or you can buy the entire latch assembly. The cost of a replacement spring is $4.99 while an entire OER assembly is $79.95. That means you'll pay more to ship one spring than the part costs, so feel free to buy something else while you're at it. You can always use something else.