Hallberg recorded eight birdies over his final 14 holes of the second round in tying the record at Turnberry in Ayrshire on a day when winds hampered the play of most other golfers.
Lehman had a relatively sedate round with one birdie and two bogeys while Langer had three birdies -- two on his first two holes -- three bogeys and a triple-bogey 7 at the 13th hole.
Four players are tied for fourth at 1-under 139. All were over par in the second round.
Only one player other than Hallberg was under par in the second round. Fred Couples had a 2-under 68 and moved into the tie for eighth at even for the tournament.
Hallberg had four consecutive bogeys and was 5-over after the first seven holes of the tournament. But, after a 40 on his first nine, he shot 31 on the second nine, including closing with three straight birdies.
His was one of the first groups off Friday. He was 1-over through four holes but posted three birdies over Nos. 5-7 -- holes he bogeyed Thursday. He had four birdies over holes 10-14 in taking the lead and pulled another stroke ahead with a birdie at 17.