Fazersharp, I have never split a caliper to replace seals, I can see how it is probably easier to clean out the seal grooves but I found that by holding one piston in & blowing the other out with a car foot pump hold the piston in with something other than your fingers & prepare to jump as they come out sometimes with force do that side clean grooves fit seals lube seals push piston back in & repeat on the other side.
For blowing out the pistons insert a adaptor that comes with most pumps the long funnel shaped one into the caliper where the brake hose connects. Don't buy your seals from Wemoto as someone on here found they didn't fit.
The adaptor required a rag around it to seal against the caliper may required to get a airtight seal.
https://www.bikestop.co.uk/oxford-air-va...gK2ifD_BwE
Good luck.
For blowing out the pistons insert a adaptor that comes with most pumps the long funnel shaped one into the caliper where the brake hose connects. Don't buy your seals from Wemoto as someone on here found they didn't fit.
The adaptor required a rag around it to seal against the caliper may required to get a airtight seal.
https://www.bikestop.co.uk/oxford-air-va...gK2ifD_BwE
Good luck.