How to replace your Macpherson struts

Revolutionise your classic’s ride and handling in an afternoon

The Macpherson strut has been a popular front suspension solution since being mass-productionised by Ford in the late Forties. The strut is a coil spring mounted over an almost vertical telescopic shock absorber. The top of the strut attaches to the car’s body, usually in a tower in the inner wing. It’s mounted in

a bearing that allows it to swivel, generally encased in a rubber bush. The bottom of the strut attaches to the hub, which is linked to the body or chassis by a lower wishbone or a pair of suspension arms. Therefore, the strut neatly acts as both a suspension link and as a steering swivel.

It’s a simple, effective and cheap to produce suspension design. The downside is that various parts of the strut can wear out or fail and replacement involves extracting the whole unit. Oil leaks from the shock absorbers, broken coil springs and worn top mounts are common – and all will spoil the car’s ride and handling. Tackling any of these faults will require removal of the struts and dismantling them on a bench. Fortunately, this is well within the scope of a DIY mechanic. New springs and mounts can be fitted to old struts. Dampers can often be rebuilt, but it is usually more cost-effective to buy whole new struts.

Safety is a key issue. The front of the car must be raised and supported securely on axle stands as considerable force will be required to undo tight suspension bolts. Compressed coil springs store a huge amount of energy and can do great damage if suddenly released. Use robust spring compressors and wear appropriate protective gear before attempting to remove them. Finally, make sure on reassembly that all mounting nuts and bolts are torqued correctly and secured with new Nyloc nuts, split-pins or threadlock, as specified in your workshop manual.