So on my Camaro, I have a Baer brake setup from about 20 years ago when they used to re-package C4 Corvette brakes into a kit.

The rear calipers in particular.

The squeak I'm referring to isn't the typical brake squeal.

What happens is, when I have the rear tires off the round, and I push the wheel in and out (for the amount of axial play I have in the differential), I'll get fairly loud squeaking emanating off the calipers, where the metal backing plate of the outboard brake pad slides against the cast iron caliper housing (the two small surfaces shown below). It's one of those metal to metal type of squeaks that you'd ordinarily squirt some WD40 to get rid of (like a rusty hinge on an old gate).




But that kind of in-out motion occurs while driving because often times I'll hear it when I go over bumps and stuff.

I originally thought it was the spring at the top sliding against the hard steel metal insert at the top of the caliper. So I took some thin gauge copper wire and wrapped it around the spring wire, and the applied some solder to it. But the squeak persisted. So the only other sliding surfaces are the ones above.

Anyone else get this kind of squeak? I've tried a small dab of brake grease in those locations, but it doesn't last long. Trying to figure out how to get rid of it permanently.