City Councilman Robert Jackson, an original plaintiff in the Campaign for Fiscal Equity lawsuit, joined advocates to renew their push to secure funding from the state for high-need schools.

Chancellor Dennis Walcott was not the only one fretting about the city’s school funding today.

While Walcott was warning about the potential loss of new funds, longtime advocates were preparing to board a bus for Albany to call for the state to settle an old tab.

They were representing the renewal of the Campaign for Fiscal Equity, a decades-long lawsuit that charged that the state was giving too little funding to high-need districts, such as New York City. The state’s highest court ruled in the campaign’s favor in 2007, and required as a remedy that the state change the formula it uses to award aid to districts. “CFE funds,” which had to be used in certain ways, flowed to the city for two years, but after the economy worsened, the state pulled back.

Now, the city’s school funding from the state has returned to pre-2007 levels, and a nonprofit group is exploring the possibility of suing the state for $5 billion in promised but undelivered aid.

David Sciarra, executive director of the Education Law Center, which picked up the CFE case after the nonprofit group that filed it folded last year, said the push is valuable even though budget conditions have not yet fully recovered.

“We know it’s going to take them a phase-in period but unless we do this, the kind of cuts that we see … are just going to continue — at the same time as they are putting more mandates on schools,” he said.

City Councilman Robert Jackson, one of the suit’s original plaintiffs, joined dozens of parents and advocates at the start of the bus tour this morning. After boarding a coach outside City Hall, the group planned to stop in Greenville, N.Y., to pick up more supporters before arriving in Albany this afternoon. Zakiyah Ansari, a spokeswoman for the Alliance for Quality Education, said she expected about a thousand people from across the state plan to converge for a march on the State Capitol.