“We’ve been having trouble with Clear Channel for years,” said William Cromartie, president of Brotherhood of Teamsters Local 85. “They want to bring in kids to work for $6 or $7 an hour and give them a T-shirt.”

About 50 Teamsters picketed Monday outside Pac Bell Park, home of the San Francisco Giants, as tractor-trailers began arriving to deliver equipment for the Friday and Saturday shows. At least three trucks turned around without making deliveries after Teamsters talked to the drivers.

The Teamsters say they should be unloading those trucks and unionized stagehands should be setting up the stage and the lights. Instead, Bill Graham Presents, San Francisco’s largest concert promoter and a subsidiary of Clear Channel, will use its own nonunion workers.

Cromartie said that means union members will miss out on about 100 jobs during the next eight days.

Calls placed to San Antonio-based Clear Channel were not immediately returned.

Bill Graham Presents said it’s never had a relationship with the Teamsters.

“We have the expertise developed to do those jobs,” said spokeswoman Sherry Wasserman. “They are using this high-profile show to strongarm us.”

“Some of their work starts today,” Wasserman said. “If they decide to honor this strike for union reasons, we will have a crew ready and we will have a show.”

Giants Enterprises, which organizes non-baseball events at the stadium, uses union workers to sell concessions, to serve food and beverages and to clean the park.

But when they sign contracts with concert promoters, “we don’t provide the service that they need for their staging equipment,” said spokeswoman Shana Daum. “We don’t dictate who they can and can’t use.”

Mark Fabris, a trade show foreman picketing on Monday, also spent $608 for two 18th row tickets for Friday’s show. He said Teamster bylaws prohibit him from crossing any picket line.

“I’m a big fan. I’ve never seen them before,” he said. “But I’ve been a Teamster for almost 20 years and I’m not going to go if this is still going on.”