I've been struggling with extracting 6-pot pistons from my ZX6-r (which has sat through lockdown and beyond and slowly seized up,) and I've been slowly trying to fix. They were stuck solid..all 12 of the little blighters.
I've seen various other tips but haven't found them easy in my garage and with limited tools;
- grease...I've only got a tiny grease pump and it didn't seem to get any pressure going. Plus it's putting lots of muck in the caliper.
- compressed air ...attaching a line always seems tricky. I've used this before on a garage forecourt but never felt it seemed very safe. Plus, with these caliper body shapes it's been quite hard to hold or fix anything to ensure one didn't pop out too far and still leave the rest.
So I found this clip online (and from Yorkshire!) and it certainly works. I split my calipers first so I could get to three pistons at a time. Jam the inside of the piston with screwdriver bits ( or small sockets) and a large allen key which you'll use to turn it. Once you start turning and it all jams up the piston will start turning. Then twist it upwards and it will slowly wind out. Amazing! And no mess.
I tried it a few weeks ago and managed to get them all turning but they were still not keen to come out.So I sprayed a lot of wd40 around the pistons and forgot about them until today. Today they just twisted out relatively easily. Genius!
https://youtu.be/HZ1SLCHR8EI?si=qUrjdM7dwXy6Itv9