Hyundai Strikers Demand End to the Graveyard Shift

SEOUL—Moon Yong-moon is tapping the brakes on Hyundai Motor Co.'s global acceleration. The question now: Could the combative union boss's push to end night work bring the auto maker's global advance to a halt?

Mr. Moon has brought a decadelong fight to end night-shift production to a head with a series of strikes that have cut Hyundai's output so far this year by 40,000 vehicles worth 804.5 billion won ($712 million.)

A fresh strike is set for Friday and the union says it plans more if the company doesn't agree to end night-shift work beginning in mid-2013