Cracking by a hydrogen embrittlement mechanism has been observed in various maraging steel Bourdon tubes. The manufacturing process involved bending the tubes after filling with a low melting point alloy which is subsequently melted out. However incomplete removal of the low melting point alloy occured leading to dissimilar metal corrosion in service, the cathodic half reaction being hydrogen evolution. Both axial and circumferential cracks were revealed, the circumferential cracks initiating at drilling marks on the bore.