Outside looking in

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How to open a stuck trunk lock in you oldsmobile cutlass ciera when you're not stuck in the trunk.

To someone who is only acquainted with modern cars that posses electrical actuators this may seem odd, so it's important to note that old cars do not have any means of opening the trunk from with the car.

Our trunk lock had been sticking periodically for a while, but I was always successful in bumping it open. At least until my wife took the car on a vacation and it got stuck closed and wouldn't budge, thus isolating her from a fair quantity of her travel supplies and generating a vast amount of annoyance. When she returned, I was going to take the car to a locksmith and have the lock drilled and replaced, but a snowstorm ruined the plans that day, and I resolved to at least try to solve the problem myself.

With exterior access denied, at least without drilling, the next option was to attempt entry through the back seat. That's actually pretty trivial, and can be done with a socket set. (How to remove your back seat)

After that, you'll have to move or remove all objects from the trunk so as to crawl through the pokey, sharp, sheet metal cross brace to fiddle with the lock mechanism.

The mechanism looks like this. If the lock cylinder is jammed, but the actual latch isn't, it will release if you put screwdriver in in the rectangular hole on the right and push the bar to the left. If the latch itself is jammed, you should try to lubricate it (WD-40) or, as a last result, unbolt it from the trunk lid. Once the latch is free and released, push the trunk open.

My trunk was stuck closed because the lock cylinder was stuck, so the next step was to remove that.

The obvious way to remove it is a metal tab riveted at the base of the trunk lid. The rivet is easy to drill, but the tab has a secret metal finger holding it in. To remove the tab, You have to depress the tabe with a long, skinny object through the holes in the lid.There is one hole in particular that appears to be perfect for the job. I had to find a piece of 1/4" bar that was 18" long from the junk pile to get the better of the tab.

The tab is attached to a claw that grasps the sides of the lock tumbler, holding it in place.
 

 

With the tab/claw removed, the cylinder slides out and the trunk can be opened with a narrow screwdriver inserted through the resulting hole. A good cleaning and re-lubrication got my lock cylinder rotating again, so that's probably the first cut approach to that problem. Replacement cylinders are available as well, though getting the keys matched is hard (see a locksmith), so the car ends up with another key.

When putting the lock back in, I used a sheet metal screw instead of a rivet.