Just a quick update… since my last post I removed both pistons and seals for inspection and appear to have found the problem…it’s a bit fiddly being a one peice caliper and not having the bore end cap removal tool (according to formula it’s only available to service centers).
The inner piston/seal was moving quite freely, probably a bit too freely as a tiny bit of fluid/air bubbles could be seen around the seal while bleeding(the side with the worn out pad). The square edged piston seal wasn’t cut cleanly and had small dags on the square edges and some bits where a bit of the seal edge had pulled away. It also seemed to have a pinch in it which is probably where it was leaking…
The outer piston was barely moving at all…it turned out the seal edge had also pulled away and was probably jamming in the edge of the piston, here’s a pic:
I used a scalpel to cut away the loose bits as best I could and reassembled it with silicone grease on the seals but it still wasn’t quite right.
There wasn’t any evidence of silicone grease on either seal when I first removed them so maybe that’s what damaged the seals in the first place?
I spoke to Formula Italy directly last week, they refered me back to silverfish who later contacted me with an returns authorisation number etc. Prior to hearing from silverfish I explained what I had found to formula italy and they agreed to send me some new seals/silicone grease etc. The replacement seals look much better and they’re all back together now with a new set of pads, the pistons both seem to be moving freely and fairly easily but I’ll have to keep a close eye on how the pads wear.
In this case the service from formula italy was very good and I’m sure silverfish would have sorted it out pretty quick if given the chance. I just hope this caliper was a friday job in the factory or maybe one that was assembled by the work-experience kid 😐 The front one has been fine so far… thanks to everyone for the input