Method for assembling an actuator of at least one air bleed valve placed between a low-pressure compressor and a high-pressure compressor of a turbine engine, said actuator comprising on the one hand a cylinder intended to be attached to a casing wall beyond which one end of a transmission mechanism connected to said air bleed valve is projecting, said cylinder being extended by a spacer for the attachment thereof to said casing wall, and further comprising a piston rod surrounded by said spacer and intended to be connected to said end of the transmission mechanism, the method being characterised in that it comprises the successive steps of: - withdrawing the piston rod such that it projects beyond the spacer, which is manufactured such that it does not have any lateral openings; - connecting the projecting piston rod to the end of the transmission mechanism projecting beyond the casing wall on the side nearest the actuator; - causing the piston rod to retract so as to bring the cylinder closer to said casing wall, the step of causing the piston rod to retract being implemented such that the mechanical junction between the piston rod and the end of the transmission mechanism is situated, at the end of this step, inside said spacer; - attaching the spacer to the casing wall; - the method comprising a prior step of scaling the actuator, in accordance with the following condition: (C-M)/2=Y; where "C" corresponds to the maximum theoretical stroke of the piston; "M" corresponds to the mechanical stop margin in the retracted position of the rod; "Y" corresponds to the distance between the wall and the centre of the mechanical junction between the piston rod and the end, whereby the centre of the mechanical junction is arranged in the spacer fixed to the wall and, on the one hand, bringing each valve into the closed position and, on the other hand, bringing the piston rod into the retracted position. - withdrawing the piston rod such that it projects beyond the spacer, which is manufactured such that it does not have any lateral openings; - connecting the projecting piston rod to the end of the transmission mechanism projecting beyond the casing wall on the side nearest the actuator; - causing the piston rod to retract so as to bring the cylinder closer to said casing wall, the step of causing the piston rod to retract being implemented such that the mechanical junction between the piston rod and the end of the transmission mechanism is situated, at the end of this step, inside said spacer; - attaching the spacer to the casing wall; - the method comprising a prior step of scaling the actuator, in accordance with the following condition: (C-M)/2=Y; where "C" corresponds to the maximum theoretical stroke of the piston; "M" corresponds to the mechanical stop margin in the retracted position of the rod; "Y" corresponds to the distance between the wall and the centre of the mechanical junction between the piston rod and the end, whereby the centre of the mechanical junction is arranged in the spacer fixed to the wall and, on the one hand, bringing each valve into the closed position and, on the other hand, bringing the piston rod into the retracted position.