Despite its reputation the Allegro was pretty rust-resistant by 1970s standards, although that’s not a very high bar. Rust is still the Allegro’s biggest enemy today, however, and should be your primary concern when inspecting a prospective purchase.
Most of the usual problem areas apply: wheel arches, inner wings, sills, footwells and the boot floor all tend to corrode if neglected. An Allegro-specific weak spot is the bulkhead; blocked heater drains and worn windscreen seals can let water collect where it shouldn’t, leading to structural corrosion that’s difficult (and expensive) to fix. Always check for damp carpets, misty windscreens and any signs of bubbling or soft metal around the base of the windscreen and up the A-pillars.
Engines are generally tough; both the 1098cc and 1275cc A-Series units will run…