Copperslip on brakes?

[Brockett]

I still don't see how putting lube on the back of the pad can make any difference.
Can someone explain it?

The wineglass explanation is not right as that introduces lubrication at the rubbing face which does not happen in the caliper. Not unless we also grease the disc!

I suspect the action of cleaning the caliper and pads is what is really curing the squeal.

[UK_Vstrom650]

If I clean the pads and caliper etc but don't use copper slip, I'm guaranteed brake squeal in the wet. If I use copper slip I never get brake squeal in the wet. I imagine it stops any vibration between the pad and piston and the water could potentially act to help resonate this? But I'm guessing.
The EBC brake pads I have at the moment don't have any shims on them, so maybe a brand with shims would negate this?  I may try ceramic brake grease next time though as mentioned by Mudster.

[kwackboy]

The shims that are supplied with some OEM pads are for heat dissipation not squeaking.

If I have to fix squeaking brakes I use copper grease on the back plate and the edges which cures most cases. Never have I had a customer come back with contaminated pads due to this practice but I'm sure some brake gurus out there from ebc, brembo may disagree but this is real world experience and not in a lab.
 
Squeaking is my opinion is down to bad fitting pads, you may not agree with me but different manufacturered pads are always slightly different in size (as are calipers) although all will fit and it's this that generates vibration so, when you grease the back plate and edges this stops the two surfaces rubbing together at high frequency.

Also a good practice is to clean the disc/rotor, you wouldn't believe how dirty they get making the surface uneven. Just spray some brake cleaner on a clean cloth and give them a wipe , never spray pads with brake cleaner either .
 

[Andy M]

There are multiple causes of squeal. One is a floor cleaner/spirograph style rotary motion of pad on  disc. It happens in the wet because there is steam in the contact patch, cooling etc. Think pan lid while boiling water. If the pad can't slide across the piston face the whole caliper makes it louder. Grease is a bit of a bodge fit, properly fitting pins and a disc without record player grooves would be better, but it can work.

Brake manufacturers (including the one I work for) say not to do it as standard as if you don't have squeal you end up with grinding paste on the back of the pad and wherever else it gets slapped by the more-is-better brigade. As a fix we'd rather you bought pads spring and pins.

The white grease was lithium, usually by Starburags. Nothing special but by marketing it a brake grease they made a killing. It's still used and you still get old boys demanding to pay ten times the price for a tub that mentions brakes!

Andy

[tallpaul]

I had no idea that Kluber Staburags could be used on brake pins. I have a tub of that stuff but I use it on splines. Looks like I now have another use for it!

[Brockett]