Abstract: An aircraft landing gear assembly comprising: a structural pin defining a first bore having a longitudinal insertion axis; a cap for covering the bore, the cap comprising: a base portion; a head portion; a body portion positioned between the base portion and the head portion; and a bolt which extends between the head portion and the base portion and comprises a threaded portion so that engagement of either the head portion or the base portion with the threaded portion moves either the head portion or the base portion relative to the other, the body being formed of an elastically deformable material such that upon tightening of the bolt, the base portion moves towards the head portion and the elastically deformable material moves radially outwards such that a contact surface of the elastically deformable material engages with an inner surface of the first bore in order to retain the cap.