Locking Gas Cap Without a Key

So far I've been trying to do at one task on the car each each day. On weeknights after work it might only be a 20 or 30 minute job, but at least it helps to keep forward momentum on the project. Tonight I thought I would take off the locking gas cap for which I have no key. I thought it would be relatively easy - drill out the lock, turn the mechanism below to unlock it and twist off the cap. Seems easy enough... Shouldn't take more than a half an hour, right? Well, I finally got it off after an hour and a half. I don't know who made the gas cap (couldn't find a manufacturer name), but my hat is off to them. They made one hell of a well built locking gas cap.

Below is what I started with. This picture is what it looked like when I first got the car home. You can't see it under the dirt, but there is a key hole in the middle of the cap.

First I drilled out the lock. This went really easy. Within a few minutes I had the lock drilled out, but when I turned the mechanism at the bottom of the lock, I still couldn't remove the cap. Infact it tightened down on the filler so that I couldn't even jiggle it anymore. I messed around using a number of different tools to turn it, but to no avail.

I then decided That if I could get the large steel lid off, I might be able to see how the locking mechanism worked. The steel cap was very heavy guage stuff and there was no easy way to cut it without risking damage to the car. I noticed a small cover around the keyhole. I removed the cover and found four large rivets holding the steel lid on. I drilled out the rivets and removed the lid. Then I cut the filler cap gasket and yanked it out with needle nose pliars. This worked well and now I could get more movement of the cap, but it was still locked on.

I could see that there were two spring-loaded locking fingers that grabbed underneath the lip of the filler neck. I tried to pull back, but couldn't get both pulled back at same time. I had to pull on them from within the narrow cavity were the lock cylinder used to be, so there was not much room for tools to grab them. Next I drilled small hole in top of each, got the sharpest needle-nose pliars I have, and placed the pliar tips in the holes just drilled. I turned the needle-nose pliars and carefully twisted the cap at the same time. Success! The cap was finally off.