A hydraulic assembly has a hydraulic unit having a hydraulic unit body, in which a delivery channel is formed, the hydraulic unit body having a hydraulic unit body base, in which an inlet mouth is formed. The hydraulic assembly has a connection having a feed pipe for receiving a hydraulic fluid and an eyelet for outputting the hydraulic fluid, the eyelet delimiting an eyelet hole and having an upper eyelet sealing surface and a lower eyelet sealing surface. The hydraulic assembly has a pipe union having a hollow cylindrical body for receiving the hydraulic fluid from the eyelet and introducing the hydraulic fluid into the delivery channel and a pipe union head, an upper gasket and a lower gasket. The connection has a shoulder having a lower projection not interfering with the lower gasket. The connection is coupled in a fail-proof manner to the hydraulic unit, preventing the hydraulic unit from rotating during assembly and use.