In my experience, the squeaking of new brakes is mostly attributable to inadequate fitting. Anti-squeal shims may be absent (if relevant), inadequate cleaning and re-lubrication of the contact points for the pads are issues (do not use copper grease here, as it is an anti-seize, not a lubricant; ceramic grease is appropriate, and red rubber grease should be applied to the boots and new seals if installed). Ensure there is no oil on the rear of the pads; copper is OK in this area. If following Brembo standards, the sliding pins should not be left dusty or rusted. The pads are too tight, causing them to remain in contact with the disc post-application, resulting in adhesion and insufficient movement away from the disc. This issue is often attributed to an overly thick coating of paint and a snug fit from end to end. It may be readily remedied with a minor file. Additionally, failing to adhere to the break-in instructions provided by pad manufacturers, such as EBC Yellow Stuff, may include unconventional break-in procedures. Typically, inexpensive discs do not induce squeaking; they are just a mass of rotating cast iron. The primary concern with low-quality discs is their tendency to distort after a short period or experience rapid corrosion on the elevated surfaces and hub owing to inadequate corrosion resistance.
