The punchline: right rear brake pads were installed backwards. Inboard was outboard and vice versa. That gave the outboard brake pad two anti-rattle springs and the inboard one had none. The pad that comes with the spring on the top is the inboard spring. The one that needs you to clip the spring on the outside of the caliper after you tighten the caliper bolts is the outboard.
The longer version: the wife was in the hospital for two months, I found myself a single dad overnight trying to run a business and the kids and the household and deal with lawyers and police and court dates and in a moment of profound weakness I decided to let the local garage work on my car to try and lighten my load some. I usually never let other people work on my cars ever. I had posted in January 2023 how the rotors had developed unusual wear and corrosion because I was hardly using them trying to boost my braking score and driving like a saint. I knew the rotors would come off kicking and screaming and they sure did give those guys a terrible hard time. They earned their flat rate pricing that night. I clearly remember when I went to pick up my car the guy was swearing up and down at the last rotor he had to do that just would not budge. It was the right rear. He was good and worn out an hour after closing as he was putting the last wheel back on and clearly ran out of new swear words to teach me. In his exhausted state he got them reversed.
As near as I can tell as the anti-squeak slowly wore out and rolled up into an orange booger and fell off the rattle got worse and worse and worse. I can't tell you how many times I inspected the brake pads to make sure they were not sliding fore-aft and they weren't. And when I checked them one last time today sure enough I found the culprit. If you pull the rear wheels off, look down in the top of the caliper. If you don't see the spring inside that top hole in the caliper, your spring has sprung, or you have the pads switched.
Anybody in the market for a pair of slightly used but otherwise perfectly good rear swaybar end links and shock absorbers? 😉 At least I don't have to worry about the upper shock absorber mounts cracking for another 6 years.
TomZweifel got a reaction from homestead in Metallic rattle right rear at low speed