So my lock tumbler is marginal and I used graphite and kept it functional but bought new keys and a new matched lock tumbler planning the advised replacement while the key still works. No dice, the pin inserted pushed past the spring with a bump when it encounters the point where it should depress the retaining spring and release the tumbler but it does not work! The spring must be worn out or have a notch carved into it and I have to get it out by force somehow. So Im wondering how best to attack this; small drills aimed at removing the spring perhaps or some other means of breaking the lock tumbler out of the ignition? The key works but its marginal and I want to install the nice new tumbler but this pin/release method is just not working.

Thanks to the pros who know what to do! Ive read the tech article and seen video instructions from several sources. Just hoping for a tip from someone who has dealt with this situation!