Hi I have removed the pistons on the front right caliper, and the pistons are missing the caps that the the left caliper has on the end. There is a rusty circle of metal in the middle that touches the pads. The pistons were seized with pieces of dust seal stuck against them. Should I replace with aftermarket stainless pistons (£45+) in that caliper?
Thank you for any help.

depends on your budget.

the pistons are plastic so providing you dont break them getting them out then they can be rused, you can make caps yourself out a little bit of metal, i dont know how important the caps are, ive ridden a 24 without them before and there wasnt any problems, i suspect they protect the edge of teh plastic.

OK definitely a small budget here. There is definitely alot more powdery corrosion on the inside of the piston seals on the caliper without the caps. The outside gold paint seems to have held up better, so maybe that caliper has been replaced sometime... I will fit new seals and watch it, maybe look into making a cap. Trying to do this bike up to a good standard as cheaply as possible.

I see this Jackson's Lair website it that yours Neosophist? It seems very comprehensive but only the page for the brake calipers is available. I would quite like to read the ground article.