SUSPENSION AND BRAKES
Test-drive any RS. Even from the passenger seat, you should be able to feel the Focus is taut and precise on the twisty bits; if it’s not thrilling, there’s something wrong.
Standard Sachs shock absorbers tended to knock, even when relatively new; replace with OE unless you’re serious about track use. Check for snapped coil springs, and avoid an excessively lowered car; 25mm lowering springs are considered ideal.
Factory-fitted bushes are particularly prone to failing, resulting in clonking on rough roads. Polyurethane replacements resolve the problem of finding obsolete OE bushes, and sharpen the handling too.
Knocking from the front could be due to anti-roll bar drop links or bottom ball joints; RS suspension arms are no longer available but they can be rebuilt with new ball joints and bushes, or RS-specific parts can be fitted into ST170 arms.
Rusty subframes are common, especially at the back. Refurbishment is feasible, and stock Focus parts – even the frame from a Mk3 Focus – will fit, providing you retain the unique RS arms and bearings. Wheel bearings are prone to rumbling, and proper RS parts are pricey – but the fronts can be swapped for heavy-duty Mondeo types.
RS front brakes were Brembo four-pots with 324mm discs as standard, which work well unless you spend time on track. They tend to squeal, and have a habit of suffering with age. Refurbishment is the solution, mated to decent pads.
Rear brakes were shared with the ST170, having 280mm solid discs and floating callipers; they tend to seize on the handbrake mechanism, but reconditioned replacements are available off-theshelf. Jack up the car and spin the wheels to check.