Don’t assume the thread is correct!

Pub discussions are rarely worth listening into, but when I overheard someone state, categorically, that all cars changed to metric fasteners by the early 1990’s, I had to intervene.  Clearly no-one had come across Land Rover Defenders (& classic Mini’s), which continued to use imperial sizes for long after this time.

I was reading a magazine which laid out many of the issues with mixing bolts, written by a Defender specialist.  The writer mentions the number of times he sees vehicles where metric nuts have been forced onto imperial sizes studs, stripping out the threads, so that they would not unscrew.  Clearly this means the job just gets so much bigger and more costly as the studs must be cut out and replaced, which in this specific case required the axle being dropped and the springs removed to provide access.

Clearly, some vehicles with long lives, such as the classic Mini and Defender, started life with all-imperial fasteners “set up”, gradually changing over time.  But given the vehicles retained many of their components through the life of the vehicles, which in the case of the Defender lasted until 2016.  According to legend the metrification at the Land Rover plant in Solihull only really got into gear after 1980, however even the very last vehicles made still retained imperial sizes in several specific places.

Clearly mixing metric and imperial fasteners can have some devastating consequences, aside from cost of putting right, potentially making the vehicles unsafe.  I heard one story of a Defender taken into a garage with a steering fault, only for the mechanic to find that the track rod end (imperial) had been fitted with a metric nut, which was causing the track rod end to move significantly!

Here at Leyton Classics we carry a full range of imperial sizes, supplying many garages, specialists and restorers, who are unable to source imperial sizes locally.  Just call us or email on