A pump includes a base, a pumping set, a first joint, a gauge set, a second joint and a nozzle. The base includes a socket. The gauge set includes a gauge, a housing for receiving the gauge and a tube extending from the housing. The pumping set includes a cylinder inserted in the socket and a piston put in the cylinder. The first joint is put in the cylinder and includes a transverse channel and an axial channel communicated with the transverse channel. The second joint is inserted in the socket, the cylinder, the transverse channel of the first joint and the tube. The second joint includes an axial channel, a first transverse channel for communicating the axial channel hereof with the axial channel of the first joint and a second transverse channel for communicating the axial channel thereof with the tube. The nozzle is communicated with the second joint.