What's wrong 2004 1.8LX Mondeo?

Hi
The noise sounds like pre ignition
Solutions here
http://yarchive.net/car/knock.html

I've never heard of a brake servo knocking - are you sure you mean the servo?

Sounds like the rear subframe bushes are worn (assuming it's a hatchback - the estate does not have them) these can now be replaced without replacing the whole subframe - don't let anyone tell you differently - difficult to diagnose without seeing the car

There's a good Mondeo forum here
http://www.fordmondeo.org/forum/fusionbb.php?

Fiesata
June 2009