In his day (a long time ago) Great Uncle David was know for his love of fast cars. His favourite was his Austin Allegro in which he achieved a British Land Speed Record (for Allegros) by driving at 61mph (downhill and wind assisted) on the A9 just south of Inverness. The Allegro had an innovative design, having no subframe. Its rigidity relied on the origami-like folding of its steel body. In fact the car flexed so much that if you jacked it up at the wrong point, its back window would pop out. The folds under the car filled with rain water and rust soon set in, requiring much welding of steel plates to prevent the car from breaking in two
An unique arrangement of pipes and pressure cylinders filled with used cooking oil provided its famed ‘hydro elastic’ suspension. This replaced conventional and more expensive springs. Again corrosion of the pipework led to regular leaks and deflation, which because the system was duplicated (but not connected) on either side of the car would cause it to suddenly list over while travelling at high speeds. Repairs generally involved pipe replacement followed by a visit to a chip shop to refill the system and a return to the garage to pump it up to pressure.
Rust, corroded brake pipes, dodgy wheel bearings, driveshafts and steering were the main causes of MOT failures and it helped if you knew a man with a dodgy garage business when it came to testing time.