1965 Fleetwood Stuck Door Lock

After years of outdoor storage, my 1965 Cadillac Fleetwood 60 Special is now indoors in my shop for work. However, the passenger back door is stuck locked and I cannot see the mechanism to know how to release it. The linkages are free so whatever is wrong is at the latch in the jamb.

The door panel is off (difficult to remove with the door closed!) but I fear I may have to cut the sheet metal on the outside just to get it open! I've soaked the mechanism in WD40 and other penetrates but nothing seems to help at all. Trying to do it by feel is the hard part so does anyone have any images or views of the mechanism or ideas that might help? The only thing I haven't tried is heat as I don't want to cause a fire.

Sadly when I moved a few years ago and put the cars into the new shop, I threw away a nice set of doors from a parts car and now am regretting it! I had no way to transport them at the time but now it seems I may have to locate a replacement door.

The shop and I are several hundred miles apart but I am trying to get advice and ideas for my next work session. Thank you in advance for any help.

I specialize in 65-66 Cadillacs and have had this happen on more than 1 parts car. Not sure it's possible get to it from the back side. It's the locking mechanism that's stuck. Not sure if it's a spring that keeps it from getting to the unlock position or a lever stuck. I've messed with these for hours and then end up using a long sawzall blade from the outside slipped between the door and door jamb to cut the striker. If you put wood shims on either side of the door, it won't get a marred up. I'm sure there's another way, but this was the fastest and least frustrating for me. If you find another way, I'm all ears. thanks, Jeff in CT

I've had four '65s myself (three Fleetwoods and a Calais coupe) but this is the first time I've have this problem. Your idea hadn't occurred to me and sounds like a winner so next time I'm there at the shop I'll give it a try! I don't have a sawsall there but I do have a jigsaw that might do it. Thank you!

I remember the shorter 6" blade wasn't long enough and had to use a longer one and bend it a bit.

Thank you again for the great idea! I've already been prying and pounding on it so much without being able to actually see what I'm hitting that some of the mechanism and possibly even the door would have to be replaced now. I would obviously need a new striker but finding one should be easier than locating a '65 Fleetwood rear door.

Does anyone know if the striker is hardened? In other words, will I need a carbide blade to cut it? Thank you.