For about 2 months now I've been fighting brake squeal on the fronts. To explain... Pads were getting a bit worn and decided to change them out on all 4 corners. Replace rear rotors as well, and used Ferodo FDB451 on all corners. Front rotors looked good and measured within tolerance. Bed them in! Brakes work fine, lots of bite, and once 'warmed' up, front brakes squeal unless I'm hard on them!!!! Certainly not the way to drive in traffic, and embarrassing to boot! What I have done since: 1) Relubed all pads/pistons & castings in case of corrosion/rust, etc..... no change 2) Replaced front rotors with another used set that was machined, still in spec, bed again.... same headache! 3) Verified pistons are all moving well... not stuck, chamfered pads on leading edges. squeal still! 4) Purchased new pads, different cheap metallic brand, lubed and bed again... headache still there! 5) Purchased new rotors, still squealing .... Arrgh! 6) Replaced pads with the original new Ferodos, re-bed, and squeals still Honestly, I have done multiple searches on squealing brakes. The original pads that I removed were the standard Ferrari pads with the 2/3 shim behind pad... never squealed. The Ferodos come with soft/spongy backing shim. The semi metallics came with a full metal shim. I have read many positive things on the Porterfield pads, but feel, if the Ferodos are bad, then they should be squealing on all 4 corners!!! I've tried different lube companies... Arrrgh! What am I missing???