Braking problem

[Fruitcake]

Hi,
I've just spent the afternoon checking the calipers, pads and discs etc on the wifes '01 Renault Scenic Diesel all of which are fine. Every so often the brake pedal "locks" to an extent. If you slow down coming to a junction it works fine but press it again at low revs and the pedal barely travels although you can feel it is very slightly braking. Blip the throttle and the pedal works as normal.
Am i right in thinking this is a servo problem?

[Krikkit]

Sounds like it, I'd certainly change the servo if I were you.

[Rich1973]

Flexi on its way out?

[littleredrooster]

Vacuum leak, vacuum pump problem or servo problem.

If (...if..) it's the same sort of pump that Pugs used to use, the diaphragm develops pinholes and loses efficiency, eventually failing altogether.