Sparkpea

Hi I’m having issues with the brakes on my 2010 crv, hoping someone might be able to shed some light as to what to look at. When braking the pedal goes straight to the board with little or no resistance, it slowly brakes. If I pump the brake in preparation to brake then I get resistance and it brakes sooner. Brake pipes have been checked for leaks, fluid is ok, mechanic isn’t sure what to try next, he’s thinking master cylinder on the servo or abs pump so I’m trying to help him do a bit of research to see if either have any particular problems or if it’s possibly something else. Has anyone experienced this problem before? All help and advice appreciated thanks