I have recently been contacted by Mr. Gerry Hawkridge who is currently rebuilding a MkIV Cobra. This is an original 12000 mile car which had been off the road for some 7 years due to a severe accident. The car still uses its original BMW front brake calipers and Peugeot rear calipers. However Gerry discovered the calipers internal thread, which take the flexible hoses, are a 10mm fine, whilst the flexible brake hoses external thread were 3/8 UNF Imperial.
His assumption is the flexible hoses are the cars Factory original set, due to his vehicles low milage and time off the road.
As this is a safety critical item I felt it important to contact the other MkIV owners via the Forum. I would suggest checking your vehicles particular components to ensure all is well, or not as the case may be.
Alan Faulkner-Stevens. MkIV Cobra Registrar