papasmurf wrote:
Not widely know but smear of copper slip or similar, (NOT on the face of the pads,) is a legal requirement in Britain because of the salt uses on the roads in winter.
Can you supply a link or quote the UK legislation? I did a search on the internet and coudn't find anything. Brake pistons are not going to be checked for grease at the annual MoT, only braking efficiency. If that legislation exists, the manufacturer would have to implement it.
The front brake pistons on my Triumph were binding. Took the bike back to the dealer under warranty where they explained that the problem was due to salt, though, exacerbated by molasses, which are mixed in with the salt. No mention of copper slip.
As Haggis states, "There are bespoke silicone or rubber lubes made for the job" for the piston and seals. The place for copper slip is on the matching faces between the brake pad and the piston.