I looked at a left-hand caliper. It can only be mounted on the axle brackets so that the bleeder valve is pointed down, so that won't fix the problem. That's why there are two right-hand calipers used in this application.
I am all too familiar with these bad boys.
(That actually comes up as the first result for Googling "seville parking brake calipers hotrod".)
I was working on them just before health and family issues forced me to set this project aside two years ago.
NAPA and the Caddy dealer are no help. That means Pick-A-Part or a place like http://www.cadillacsonly.com/
Or I suppose I can cut, bend and re-weld the left-hand bracket; the lever arm looks like it will work just being flipped over.
Can I find the brackets on any other GM vehicle of the era? I've read that these are 79-85 Seville and some Eldorados. With my luck, Pick-A-Part will no have any . . .
P.I.T.A. is what they really are.