Brake booster Volvo Amazon (B18 1/2-circuit)

When rebuilding the servo, repair kits with gaskets and seals are the parts you most often start with, complemented by brake pipes, nipples and a hose clamp to seal up the lines toward the master cylinder. Grease and plastilube belong with the installation so the rubber and moving surfaces don't run dry.

Since the design differs between early and late 122s, it's worth checking whether the car has one or two brake circuits before choosing parts, so the gaskets and pipes match the right system.