Half-shaft failures




It is difficult to understand Mr. A. J. Burt’s statement (May issue, page 343) that he was told by the former owner of his Morris car to avoid letting out the clutch when facing up steep hills in order to avoid fractured or stripped half-shafts. There can be very little load on a half-shaft when the clutch is disengaged and I do not think that the implied reasoning can be supported. It sounds as if the former owner had himself experienced a broken half-shaft and I suggest that what actually happened to him was what happened to me with the original 3-litre Invicta half-shafts on Beggar’s Roost in April, 1927. The fracture, in that case, was due to violent, but intermittent, wheelspin on a loose surface. I disengaged the clutch to keep the engine running when the car came to a standstill and subsequently found that a shaft had fractured. I think the former owner of Mr. Burt’s Morris probably had the same experience but misunderstood the cause.

Had I been knowing enough to tighten up the Hartford shock absorbers before attempting the ascent, there is a reasonable chance that it would not have happened – not just then anyway.

I am, Yours, etc.,

London, N.W.8. – John H. Ahern.