citroen dispatch diesel non turbo no abs 04 reg?

when you have the engine running disconnect the pipe from the brake servo by the brake master cylinder if it is not sucking in air then there is a blockage in the line to the vacumm pump or the pump have failed (Yes I know you said you had changed it) or the drive for the pump may have failed, but to be honest the way you discribe it, it sounds like the brake servo may be sticking or failed. You could try spraying a SMALL amount of WD40 into the brake servo via the hose connection hole previously mentioned and see if that frees it of. If not get a new one fitted

arizona kid
April 2011