Method for making a ready-to-bond modular element and assembling method

The invention concerns a method for making a modular element, such as a motor vehicle roof or door, ready to be bonded onto a frame or other surface with a bonding bead in accordance with a bonding pattern, closed in particular, comprising the following steps: producing, in particular in a mould, a composite shape bonding bead reproducing the bonding pattern and having a specific cross-section, comprising a structural bead linked to a protected adhesive coating or capable of being activated and to the element. The invention also provides producing in a mould a homogeneous bonding bead having at least a protected adhesive surface or capable of being activated. The method for mounting the modular element consists in removing the protection or activating the adhesive coating and in pressing the modular element on the frame or like surface. The invention is applicable to car manufacture.