Labor leaders say they will not help Gov. Jerry Brown win voter approval for a plan he is set to propose to reform California\'s public employee pension system.Brown wants to make changes in the boards of the two largest pension systems for state workers, the Los Angeles Times reported. Those changes would have to get on the ballot and win favor with the voters.\"Our unions aren\'t going to put up a penny for a pension initiative,\" said Dave Low, chairman of the Californians for Retirement Security, a labor coalition.Brown briefed state employee union leaders Wednesday on his plan, which would raise the retirement age, and change the system to combine aspects of a traditional pension plan with a worker savings system like the 401(k).Details were to be publicly released Thursday, the newspaper said.Brown, a Democrat, has been pushing for pension reform since his inauguration. He outlined his plan in March.\"The current system is not sustainable,\" Gil Duran, a spokesman for the governor, said.Republican legislators say the pension plan boards are weighted too heavily toward labor and need more people with financial expertise.