Maybe reaching but have you tried WD-40 or silicone spray into the jammed mechanism?
Also looks like 2 sq opening for key & dead bolt lever have you tried using both at the same time?
Add more leverage and force it? sq shaft & wrenches??
I'm groping but trying to cut the bolt in place likely not going to be fun???
I found this thread because the Perko lockset on my companionway door “froze” in the locked position on Saturday. The key would cycle CW and CCW. The handle would rotate CW and CCW, but very stiff. The lockset would remain solidly engaged. I got online and found endless and ugly stories about the Perko lock failures and subsequent fixes/replacements. This lockset is original equipment (1976). It is set in an exterior aluminum door. Unsure as to the model number – pictures below.
After reading a number of accounts, I was thoroughly discouraged, envisioning one of “those” projects that eats time and money and provides questionable results. Then I saw Bacchus’ common sense post.
I removed the exterior plate and knob. Then, using WD40 with the straw attachment, sprayed too much into every nook I could access. Took a break to let everything soak and grabbed the square handle latch with vice-grips and slowly, with a little force (it was very stiff) cycled it back and forth. Voila! The spring took over and the latch works fine. Note that the problem was the latch and not the deadbolt. Due to the weather seal on the door, there were no sightlines to distinguish which was the problem.
At least in my case, it appears that decades of crud had bound up the mechanism. No broken internals. Bacchus’ approach is a worthwhile starting point for Perko lock problems before more radical means are employed.
Once again, TF comes through!
