you door will not open so access is super limited, and the lock does not like getting tampered with, unless door is opened first.
all you can do I think is break the rust free,
one trick is using some minor heat, use heat gun or old hair dryer (heat gun)
heat it up , and stop that, and use spray lube now, so that as it cools the oil sucks in to the rust bound lock.
what new spare one can do progressive inside, car and door shell progressive destrution, until it is only a bASE shell and levers inside are now free, and free to pry.
grind or drill out all those pin rivet and split the sucker top to bottom. (Drimmel tool or use drill bits, and drill it to skeleton and then rip it to pieces, total destruction of forward lock wall , steel. this will work but is tedious but all old cars are.
i think the spare lock path is best, here. wrecking the old one, fully, from inside.
all you can do I think is break the rust free,
one trick is using some minor heat, use heat gun or old hair dryer (heat gun)
heat it up , and stop that, and use spray lube now, so that as it cools the oil sucks in to the rust bound lock.
what new spare one can do progressive inside, car and door shell progressive destrution, until it is only a bASE shell and levers inside are now free, and free to pry.
grind or drill out all those pin rivet and split the sucker top to bottom. (Drimmel tool or use drill bits, and drill it to skeleton and then rip it to pieces, total destruction of forward lock wall , steel. this will work but is tedious but all old cars are.
i think the spare lock path is best, here. wrecking the old one, fully, from inside.
http://www.fixkick.com