Pavin was among the early starters and looked set to take a commanding lead before finishing with a double bogey 6 at the 18th after hitting his second shot out of bounds.
Langer had to deal with a biting cold wind later in the day but also got to 6 under before bogeys on two of the par-3 holes. At the short 13th, his tee shot landed in a deep pot bunker, and he then missed the green at the 16th with a 5-iron and was unable to get up and down.
Langer has 10 wins in three years on the Champions Tour, but is still looking for his first victory in a senior major.
"I could have putted a bit better," Langer said. "The ball did not drop for me like it did in the first round."
Americans Dan Forsman (71) and Larry Mize (70) were also tied for second.
Tom Watson, who missed the cut in his last British Open appearance at St. Andrews last week, had no problem making sure he will be around for the weekend this time. He sank a 15-foot birdie putt on the last green for a par 71 to remain 3 over.
However, Bob Charles of New Zealand — the first left-hander to win the British Open in 1963 — bid farewell from the tournament after he shot a 78 to miss the cut.
At the age of 74 and after a career that brought him 64 tournament victories, he announced that it was his last round of competitive golf. Unfortunately for him, he signed off with a double bogey at the 18th.