Hi Smitty-

I have a 93 245. It had the same symptoms that you describe. For me, removing the entire lock assembly, cleaning and re-lubing it, and then reinstalling it has had great results.

I do not know the proper method of removing all the accumulated crud in there.

I used goo-gone orange to de-grease it, pb blaster and a wire "toothbrush" to clean a bit more, followed by "The Works" toilet bowl cleaner to remove/loosen rust, followed by dremmel to clean/ polish everything I could reach.

Then dried it, pb blaster again to penetrate and get rid of any last little bits of water, then dried with a q-tip and rag, then white lithium grease, reinstall, and a bit more grease.

I think that you might be able to get away with just removing the hatch panel, and spraying a decent penetrating lubricant in there.

There was tons of junk and little bits of rust that seemed to impede proper operation on mine. Plus I like playing with stuff to figure out how it works, so it was a fun 2 hour project for me.

Nothing tricky, except for the order of operations to put it all back in. Might make sense to write down the disassembly order to make sure you put it back together in the right order. I messed up a few times.

good luck!