My kids' 1992 940 was suffering from various maladies of under-maintenance (tough to repair by yourself in midtown Manhattan!) so I brought it back to Iowa to do some work. I asked a local tire shop to change the snow tires and they tried opening the trunk in which I had placed some tires, only to permanently lock it using the valet setting. As you all recall, the valet setting locks the trunk but allows you to open the car doors. No amount of turning on the master key would open this lock cylinder. I assumed that spray from the rear had corroded it over time and the kids had never lubricated it.

I sprayed the innards of the cylinder liberally with penetrating oil. The little straw on the spray can only reached about 1/2 inch into the lock. I bought a cheap veterinary syringe with an 18 gauge, 1-1/2 inch needle to inject the penetrant fully into the lock. I did this several times over two days.

I then placed the key in the lock and whacked it several times with a rubber mallet. This did not succeed in freeing it up, so I removed the key and placed the plastic cap of a spray can over the cylinder (it fit perfectly) and whacked a whole harder. Success! The key turned the cylinder clockwise with some effort and it opened up the trunk. I then sprayed Houdini lock lubricant to keep it functional.

I don't want this to happen again on their watch late at night in Brooklyn. I am probably going to disable the entire valet mechanism on the trunk as it is marginally helpful while being a major pain when it fails. I may permanently remove the actuating rod which seems like a better idea than epoxying the lock shut. Any thoughts from Brickboarders?

Steve,

I thought there was a special Valet key that would not operate the trunk or glove box. Is there a different set up for the 940s?

My 90 740 wagon hatch lock has been seized since I got it but it unlocks with the power locks.

I am not clear on the cap that you used. Did you manage to slide a hollow cap around the cylinder and then just whack it so all the force hits the surface?
--
Paul NW Indiana '89 744 Turbo 180K/ '90 745 turbo 145K

There is a shorter valet key that will not open the trunk or the glove box, but I was not using that to open the trunk. In my case, the cylinder seized AFTER the valet feature had been activated. The longer master key would not move the cylinder. Because that feature also disables the electric lock, there was no possibility of opening the lock without freeing up the cylinder.
In your wagon's case, it is easier to access the lock because you can climb into the rear compartment. Not so with the sedans. My advice: take off the trim, remove the lock cylinder and free it up if you can to prevent future grief if someone indeed is able to turn it with the valet key. It may end up (as mine was) to be a one-way turn.
I found a plastic cap from a spray can that was about 1-1/8 inch in diameter, just big enough to extend to the edge of the lock cylinder cover plate. I soaked the cylinder with penetrating oil, then put the cap next to it and whacked it several times with a mallet. The force went into the cylinder. It finally jarred loose the cylinder so I could, with some effort, turn the key and open the trunk.

Given the grief a locked trunk can cause, it might be prudent to drill two one inch access holes in the body lower trim piece covering the latch. This latch is bolted into the body with two 12mm bolts, each one 2-5/8 left and right from the center of the latch and 1-1/2 inch down from the curve in the trim piece. Drill two access holes in this trim piece so at some future date, you can easily release the entire latch mechanism with a 12mm socket and some extensions through the ski hole in the rear seat.