What's Chris's issue with copper grease? 
Shims are applied to damp out squeal, which is USUALLY caused by resonance from a badly seated pad, allowing it to rock at high frequency which sounds like a squeal. Ask Kai, used to be a member here. His car had cheap ferodo pads fitted that had a VERY thick brittle paint on the back(ing) with no shims.
Over time with piston pressure, the paint cracked, then the metal backing rusted causing a high spot in the pad back. They rocked in the calliper so squealed ....so bad I could hear him braking for junction 11 of the m4 and got progressively louder as he got near the house to have it fixed
Pad material can also squeal, but less common these days, unless you fit a certain batch if tc pads a year or two ago.
Shims are usually a softer metal. Drilled brass on some bike pads. Oe omega pads have riveted on shims on all 4 pads, tc pads are much cheaper so have only one shim per side. They are shims in this care because they are a spring metal type material with a rubber pad stuck on top of that. It is a metal shim under the rubber.
The reason the shim goes to the non piston side is because the calliper is more likely to resonate than the piston side which is insulted from further metal components by seals and fluid. Not sure if the piston material is actually softer as well, but it has a brass colour. Where as the calliper is a big cast solid lump with a wider area on the pad.
Copper slip? Its shite, that's what's wrong with it.
....that's not true actually, its shite at stopping brake squeal, proof being AndyB by definition is Mr a Copper slip by confession, smears copper slip all over his pad backs, yet here he is moaning his brakes are squealing
It's accepted, for some reason, that smearing your brake pad backs with copper slip will silence a squeal once it starts. This is utter bollards. Ask AndyB(although he'll deny it) and Kai, who had gallons of copper slip dripping off his calipers from the heat, but yet they squealed like a stuck hurd of pigs.
It will however, go some way to stopping corrosion forming on the calliper and piston so high spots don't form from corrosion so readily. There by keeping squeal at bay.
Copper slip will not, however, cure a pre exiting squeal, simply by smearing it on the pad back for more than a couple of days at most until the copper slip is washed out or swished aside by calliper pressure.
But if your brakes aren't squealing, don't worry... If they do, fit shims off the old pads or swap the shimmed pad to the calliper side. File any high spots off the calliper and piston and make sure everything is seated correctly .
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Topic: front brake pads (Read 4657 times)