Wellington Central Police Station was built in the late 1980s. Its 10-storey tower block featured robust X-bracing around the perimeter and strong floor diaphragms to distribute earthquake actions amongst the perimeter frames, thus making it extremely stiff. To provide the ductility required by the 1984 Loadings Standard, the tower block was supported on a base isolation system that allowed up to 400 millimetres of movement in any horizontal direction. This paper describes investigations into the continuing serviceability of the base isolation parts, and the remedial maintenance required.