On holiday and our hope evo race piston isn’t returning. Far from tools and bike treks in Ambleside being closed is there a quick fix for a non returning piston?

Clean them up and force them back in with a plastic tyre lever.

Wd40

And then replace seals once back home?

I’d try silicone spray on the seals and push back into the caliper, even “back to black” or similar, maybe dispensed into the lid and applied with a small print brush or cable tie

Quick clean and careful application of suitable brake fluid to piston normally works for me.

If you’re referring to the master cylinder piston, they can crack, if silicone spray doesn’t release it, dismantle and check it over.

Is the stop plate tight, has the screw come loose (t10 security torx)?

Ye it’s the master cylinder which is not returning. It’s behind the securing plate with the security torx screw. I’ve ordered the seal kit. But I’m nowhere close to fit it. Without a fix there will be no riding. If we find a mechanic I doubt they’ll have A the seals and B the time to drop everything to do it. I just wish I’d packed a tool kit!

If you’re in Ambleside, head to ghyllside cycles – down the alley oppose the cinema. They’re super friendly.