State Sen. Steve Glazer, D-Orinda, who has relentlessly railed against BART, its labor contracts and financial mismanagement, told The Chronicle Wednesday that he will vote against Measure RR, the $3.5 billion property tax proposal on the Nov. 8 ballot to upgrade the regional rail transit system.

“Despite my strong support for the BART system, I am going to vote no on the bond,” he said. “I don’t think we should reward bad behavior and expect anything to change.”

Glazer’s opposition is bad news for the Yes on RR campaign, since the senator’s district covers most of central and eastern Contra Costa County and the Tri-Valley in Alameda County — areas where support for the bond measure is not considered particularly strong.

Nick Josefowitz, a BART director from San Francisco, speaking for the pro-bond campaign, declined to discuss the significance of Glazer’s opposition other than to say the campaign’s efforts were focused on voters rather than politicians.

“We have a really big district at BART, something like 1.8 million voters, and we need to get more votes to win than our U.S. senators need to win their elections. It’s understandable in a district that big that some people will be excited about what we’re doing and some won’t.”

For the measure to pass, BART needs to win support from a two-thirds supermajority of voters in Contra Costa, Alameda and San Francisco counties combined. The three counties make up the BART district. In 1962, voters in those counties were responsible for passage of the bond measure to build the system.

Glazer’s opposition comes as somewhat of a surprise to bond backers who thought they had persuaded him not to publicly oppose Measure RR.

Glazer has made clear his dissatisfaction with BART management, especially over what he sees as lavish labor contracts.

In February, as BART directors contemplated a bond measure, he organized a group of elected local and state officials who threatened to oppose any proposal asking voters for funds unless BART negotiated a “financially responsible contract” with its labor unions before going to the ballot.

BART officials quietly bargained a four-year contract extension with its unions, announced in April, that ensured no labor strike would take place in 2017 when negotiations for new deals were scheduled. The extension included 10.8 percent in raises through 2021.

Glazer initially described the deal as “a good first step” but said it needed improvement. He said Wednesday that the contract extension succeeded in staving off a possible strike for five years but was too costly and failed to address critical issues, including training replacement workers and assuring any bond money can’t be spent on labor.

Recent stories of excessive overtime, on-train security cameras that don’t work, salary bonuses for workers and big raises for BART managers, he said, persuaded him to oppose Measure RR.

“We all recognize how important BART is to the whole region,” he said, “but at some point there needs to be a level of accountability for how they’ve conducted themselves.”

Josefowitz said BART directors and other bond supporters have been getting a supportive response from people around the district as they spread the message of BART’s need to upgrade the 44-year-old system troubled by aging infrastructure and overwhelmed by record ridership.

“Everyone in elected office is asked to take positions all the time,” he said. “What we’re really interested in is voters taking positions — and we’re hearing a lot of support.”

Glazer said that while he will vote against BART’s bond measure, he has not yet decided whether he will campaign for its defeat.

“At some point, with all this irresponsible behavior, you have to say no,” he said. “That’s how I feel about this election.”

Michael Cabanatuan is a San Francisco Chronicle staff writer. Email: mcabanatuan@sfchronicle.com Twitter: @ctuan