These are not screech plates, or as they are more aptly called as brake shims. These basically reduce pad judder due to accumulated brake dust and helps provide a tight fit for the brake pads which in turn helps them stay in place when brakes are applied and don't move in the direction of the wheel and cause one sided pad wear. Also similar to your point, it does reduce squeaks since it helps reduce pad movement.@sunnylovesalman, apart from the jugaad brake pad shim that you've replaced, I'd like to know more about the other modification you did to the caliper holder, as I couldn't see the job carried in the second picture. The reason your brake noise is reduced is because the shims have provided for a more tighter fit of the pads inside the caliper, and in the process makes the movement of the pad less due to the wheel motion when brake is applied. This is what causes irritating squeals, along with a crappy worn out brake pad.
On my R15s, I've changed both my front and rear tires, a couple of months back, along with brake pads and fluid. When it comes to replacing, brake pads, fluid, brake lines, I always prefer doing it myself, and so far I haven't lost anything in the process per se or nothing unduly did fall or did I miss anything, but since you did bring this point up, it piques me as to why my R15s didn't have these shims.
Cheers!
VJ






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