Following an uneventful flight from Antigua-V.C. Bird International Airport (ANU), the aircraft made an approach to runway 10 at John A. Osborne Airport, Montserrat. After a normal touchdown the pilot applied the brakes and noticed that there was no resistance from the right brake pedal. While maintaining directional control with the rudder pedals the pilot tried to “pump” the brake pedals but this had no effect on the right brakes. To avoid departing the end of the runway the pilot applied left brake and allowed the aircraft to veer left onto the grass just beyond the taxiway exit. The aircraft struck an embankment located 20 m north of the runway edge, about 150 m from the end of the runway. The impact, which was estimated by the pilot to be at about 10 kt, resulted in damage to the nose structure and caused the nose landing gear leg to collapse. The left wing tip leading edge was also damaged when it struck the embankment. After the aircraft came to rest the passengers were able to exit the aircraft via the main door The probable cause for the loss of right braking was trapped air in the right brake hydraulic lines. This air may have been present prior to the O-ring seal removal but was more likely to have been introduced during the seal removal and replacement. The engineer had carried out a brake bleeding procedure but he had not completed the full procedure as described in the AMM. He had not opened the bleed screw at the top of the right landing gear leg, and therefore air may have remained trapped in these lines. The investigation revealed the existence of several different brake bleeding procedures. The aircraft manufacturer had three different brake bleeding procedures, namely the Islander AMM procedure, the Trislander AMM procedure and their own production procedure. Three engineers from three different maintenance organisations had suggested that sometimes the manufacturer’s procedures were inadequate for completely bleeding all the air out and that a hand pump attached to the brake bleed screws was sometimes required.