Technical Need Help to disassemble 32 column drop !

Can anyone tell me how to remove the pie shaped key from the sliding bolt and release the plunger and spring after removing the lever and bolt from the housing? This is the large sliding bolt that operates the whole mech. I have heard 32 toi 35 use this same internal bolt. I would really like to locate a smoother one than mine (has some wear and burrs.)

thank you