Which companies in the 1970s stoled their employees pension plans?

Who says any did?

Was this for homework? If so, you need to do your own research and try to find it. If you're just asking, are you just assuming some company is always stealing pension plans? (And if that's homework, it's a terrible question, but it's making an implication that some company is always stealing pension plans.)

The impetus behind ERISA (the Employee Retirement Income Security Act) was less a matter of companies "stealing" money from their pension plans than it was an issue of underfunded and poorly managed pension plans that didn't have enough money to properly fund their employees' pensions. Studebaker was perhaps the biggest and most famous failure of a pension plan - but that was in the 60's.