The basic principles of hydraulically-assisted power steering have stayed the same for decades. Even today this Army-produced clip about how a series of pumps and valves help point the wheels is just as relevant and informative as it was for skinny-armed recruits back in the Fifties.

Power steering has been almost a given in cars for a long time, but explanations about how it works tend to be in short supply. This clip shows why as it describes what turns out to be a pretty complex system involving pressure differences and control valves and fluid flow.

But, like we said, still relevant — and probably for years to come.