1989 IROC. Has anybody found a decent, LONG LASTING, lube for the caliper slide bolts?

I've used the little packs of brake grease from AutoZone, motor oil, wheel bearing grease, rear axle lube....whatever I use, it dries up and gets sticky. I know when my caliper slide bolts are stuck is when the car pulls to one side or the other when braking.

For the time being, I'm using WD-40 on the slide bolts. It only lasts about a week but doesn't turn into cement like the other stuff. It sucks, though, having to spray the bolts so often just so the brakes will stop without pulling. Any ideas?