Repair techniques, due to improve masonry and re-establish the ability of torn walls to transfer loads, have been applied since the 1920's. Systematic follow-up examinations concerning success or possible subsequent damages had not been taken until recently. Different methods were used in order to find out position and corrosion progress of inserted reinforcement, remained voids in the grouted masonry and general information about the behaviour of the various materials used. The strain in prestressed anchors was measured, steel rods extracted and their adhesion to the masonry was examined. There were positive as well as negative results.