For its age, not much.
Springs have broken in the seat.
Several tie-rod ends for the steering have worn or popped.
Steering box renewed.
2 clutches replaced.
Windscreen glass replaced (old style shattered after small rock chips).
Rust in sills (cut and replaced).
Fuel gauge always pretends to give reading (never right).
Electrics on the way out (old cotton wrapped wires are beginning to fray).
Interior door handles loose and doors sag slightly.
Starter button takes a fair press to contact.
Gearbox very average (likely to need replacing soon).
Moter underpowered, even with new rings.
Front window vents leak in heavy dew.
Windscreen wipers painfully slow, not good in traffic.
To own an FJ you really need to love it. Everything that mis-behaves or breaks down on the car is added to the 'character' list or forgiven for its age.
All in all the things that are wrong with it don't necessarily stop me from driving it. It just makes for difficult driving in an old car. You need to give everything an extra 3 seconds to happen.
If you get out of the 'J' and into a new car, it is like stepping off the Bounty and onto the bridge of the Star-ship Enterprise.
The car has a heap of personality. It never goes anywhere without a good look from drivers or pedestrians. It's no show car, but still gets the comments.
You get around at about 80 km/hr, but people forgive you for going too slow on the road because it's an FJ.
Mechanics take it in without question. A lot of the old boys cut their teeth on them as apprentices and they are simple as looking sideways. They always get the comment 'She runs well!'.. they should try driving it for a couple of hours.
The car handles like a dead cow. You slow before you get to corners.
The brakes do their job at 1950's speeds, but you can't work them too hard as they overheat quickly.
Upsized radiator is a must for hot weather driving (or have a big bottle of water on board).
Parts are generally available as Repro items, but are beginning to get into the enthusiasts price-range.
Apart from flat batteries, the J has never not started.
Don't buy one unless you know your early Holdens and the rust problems they have. Expect rust, leaks and oil drips, and you won't be disapinted.
You need to give them a bit of attention before each drive.
Don't expect to own one as a cheap daily driver, they do wear out!