Does the car run rough?
No, well on the odd occasion it will run a bit lumpy on start up, however I dont think that would be the problem.
Get a large can of WD40 or carb cleaner and spray it round all the joints on the servo with the engine running. If the tone in the engine picks up and it runs better then the joint you're spraying is leaking. Also works on any part of the induction system.
Thanks mate, will have to try that
Master cylinders do not cause air leaks. If there is an air leak round the master cylinder then it's servo related. Pedal travel is a hydraulic problem within the brake circuits.
When you say brake circuits, what you mean exactly? Do you mean abs related? I had the abs removed the other week too.