In the 3 years I had this car, nothing major went wrong with it. My Grandfather willed me this car, and he was the original owner, bought it new in 1968 for $2400 CDN. He did replace the tires once (4), and other maintenance items like brakes, tune-ups etc. He did repaint the car in 1981, because of bad oxidation, and even kept the ugly light green colour!
When I had the car I only had to get the (original) radio working again (loose wire). I did not have the car long enough to experience any big troubles, but people I know who own them report excellent reliability.
As a teenager, of course I abused this car, it was indestructable!
It had the 1600 OHC, 4-speed manual, and solid axle (being a wagon), and was great fun to drive, outrunning then current-model cars to the surprise of their drivers. (My 510 with 3 friends and myself beat an '86 Corolla SR-5 with just the driver in it, for example).
But the curse of rust had taken its toll over the years, and one day I was making a low-speed left turn when the car started to only go straight. The front wheels were crabbed in opposite directions because a welded front suspension member had rotted away, resulting in a tumble into a ditch. I was okay, but the 510 would not drive again.
I sold it to a friend of mine in high school for $100 - he had a '69 510 sedan which he needed and engine for - so in a way it still lives on.