Rust.
Very reliable little car with a nice looking body.
One of the most underrated classic cars.
Rust is also my problem, had it removed twice. Great little car though.
I still own a 1974 Deluxe with 120000 km on the clock. It was my wife's car since 1979. Very reliable except for rust. Everything still original, even spare wheel. Got special place in my garage only use it for drive now and then.