Spongy brakes following pad inspection - ?

[Pip1968]

In short I took the pads out to have a look see and compare them to some spares I bought. I was unsure if the spares were the correct ones. Anyway they were not the right ones and since puting it all back together the brakes feel spongy. Not tight at all.

I have been for a couple of short runs and pumped the brakes but they are still spongy.

Anyone any ideas what I have done wrong - ??

Presumably I have allowed some air to get in.

Pip