Abstract: A twin-tube shock absorber of a "sealed for life" construction comprising an outer cylinder (1), an inner cylinder (4), a piston rod (5) housed within the inner cylinder (4), a guide member (8) to locate the piston rod (5) within the inner cylinder (4) and a metal insert seal (10) located inside the top end of the outer cylinder (1), above the guide member (8), and slidably embracing the piston rod (5). The guide member (8) is clamped in place within the shock absorber by a circumferential shoulder (17) in the outer cylinder (1), which is produced, after assembly of the internal parts, by a lateral swaging operation which creates a reduced diameter, parallel portion of the outer cylinder (1) above the shoulder (17).