What might be the biggest battle is developing just now, after the Obama administration warned in a letter to Brown earlier this month that his pension changes make California transit districts ineligible for federal transportation funds.

In doing so, Labor Department Secretary Thomas Perez is siding with the unions.

Up to $4.3 billion of transportation funding is at stake, Brown has proposed excluding the transit workers from the reform plan until a settlement can be negotiated.  

The changes in California's pension system primarily affected CalPERS, the California Public Employees' Pension System, and CalSTRS, the California State Teachers' Retirement System.

When Brown first unveiled his plan, he said it would save $4 billion to $7 billion. When the final bill was worked out, the savings had grown to $30 billion, although the governor gave no time frame for achieving that new, much bigger goal.

Today, nearly a year after the reforms were adopted, here's a look at the four changes that have caused the most rancor – and are expected to have the greatest impact in stabilizing matters.  

Salary caps

THE CHANGE: For the first time, a ceiling has been imposed on the salary figure used to calculate benefits.  It is $110,000 for those covered by CalPERS and $130,000 for CalSTRS workers. The number for teachers is higher because they do not pay into Social Security.

THE SKINNY: This is one of those changes that sound good but, in actuality, have little effect, because they affect so few people. The Bay Area News Group obtained salary numbers from the state Controller's Office which showed that just 1.6 percent of about 250,000 state workers earned more than $132,120 in base pay in 2012. The data showed that 3.7 percent exceeded $110,100. Only workers hired after Jan. 1, 2012, are subject to the cap.

Pension contributions

THE CHANGE: All state employees will have to kick in 50 percent of their annual pension contributions.

THE SKINNY: This is the only aspect of the bill that applies to all current workers, regardless of date of hire. The increased payments are to be phased in over five years as union contracts expire. Across the state, many employees already make contributions at the mandated level. The cost is high. For instance, Southern California Public Radio reported that Orange County sheriff's union members pay 13 percent of their salaries to the pension fund. That equals $7,000 to $14,000 per year, depending on rank for those making $61,000 to $108,000 per year.

No more air time

THE CHANGE: Workers can no longer purchase up to five years of service time that counts toward their pensions.

THE SKINNY: It's unclear how much ending this practice saves, but the outcry against it has been intense, with some calling it "corrupt." As the deadline for applying approached in January, CalPERS reported that 12,000 workers applied to buy service time, more than 11 times the usual number. The pension giant said the cost to taxpayers could not be calculated until after the pensioners had died. However, it added that if the system's investments generated a return of 7.5 percent per year, the benefit would pay for itself.

Retirement age 

THE CHANGE: The age to take full retirement was raised to 67 from 55.

THE SKINNY: California is just the fourth state to raise its retirement age as way to save money. Illinois and Missouri pushed theirs to 67, while Minnesota's is at 66. Most of the rest are at 60 or 62. By raising the age, workers contribute to the pension fund for more years. In addition, with life expectancy at 78, retirement is lasting longer than it did when Social Security first put the end of working life at 65. The unions, not surprisingly, aren't happy with it. "Sixty-seven is kind of advanced," said Frank Wells, a spokesman for the California Teachers Association. "We don't want to see him doing anything that would make it more difficult to recruit and retain teachers."