When I rode the bike home from picking it up the front brakes were very stiff. The previous owner had informed me that he had just bled them and hence the stiffness. The bike stopped... but I had my suspicions.
I purchased Brembo seal kits from Munich Motorcycles in WA ( I get a lot of stuff from them- great business). The kit includes two piston seals, two dust seals, a small brake fluid channel seal and two new bolts.
I pulled the calipers apart as per the Clymer manual- first removing the pins and the pads and setting them aside. Next the caliper halves were split by removing the centre hex bolts. As there were new bolts in the seal kit I discarded the old ones. The dust seals were completely destroyed. And it got better from there.
The first problem arose when it came to removing the pistons- they were very seized. There are many strategies described to solve this (Clymer suggested the compressed air strategy) but what follows is what worked for me.
I gently heated the outside of the caliper half using a blow-torch- not super hot, I was still able to pick the caliper up from the edges. Then I applied a C-clap to the centre of the piston and gently compressed it a few millimetres to break the seal. Then I was able to lever the piston out using two fine flat head screw drivers at 180 degrees to each other.
Once the pistons were out I was able to pry out the piston seals from the caliper halves using a plastic tool.
The crud in the calipers was pretty impressive- see the pictures. I spent a long time cleaning them with acetone and q-tips. I also flushed the brake fluid channels using acetone, compressed air and then DOT 4 brake fluid.
The pistons were coated in a kind of rusty varnish but they didn't have any obvious pits or scores. I carefully cleaned them up using 1000 grit wet sand paper. When I had finished each piston would gradually fall into the cylinder it was placed in. Perfect fit, not catching.
I cleaned up the pins using red Scotchbrite.
When everything was clean, I reapplied the new seals with a smear of the Brembo grease which was provided and put everything back together. I also coated everything in clean brake fluid. New pads were installed.
