Just weeks before the general election, Mayor Bloomberg may have cleared a major hurdle yesterday when his administration reached a tentative contract agreement with the teachers union.

Signaling the end to an almost two-year stalemate, the union president, Randi Weingarten, and the labor commissioner, James Hanley, shook hands at 6:15 a.m. yesterday after an all-night bargaining session. In what the mayor called a “historic agreement,” teachers would receive a 15% total raise over 52 months in exchange for several work reforms.

The agreement would require teachers to work an additional 50 minutes a week, lengthen the school year by two

days, and put an end to seniority transfers that allow teachers with seniority to “bump” a new teacher filling a position in another school.

The contract must be ratified by the union membership and approved by the city’s Panel for Educational Policy.

A Democratic political consultant, Scott Levenson, called yesterday’s agreement a “great victory” for the mayor.

“Of the remaining contracts with labor unions that have yet to be settled, this was the biggest one to him and his candidacy,” Mr. Levenson said. “And the fact that it looks like he’s been able to keep the UFT either out of the mayor’s race or in his corner is the biggest victory he could have had today.”

Ms. Weingarten and Mr. Bloomberg also declared yesterday a victory for the nation’s largest public school system and its 1.1 million students.

Less than a month ago, Ms. Weingarten and the union’s more than 100,000 active members threatened to walk off the job or endorse Mr. Bloomberg’s Democratic challenger, Fernando Ferrer, if the mayor did not finalize a contract by early this month.

Yesterday, a different tune was being sung as the schools chancellor, Joel Klein, wrapped his arm around the union president and planted a small kiss on her forehead. A slew of UFT members broke into applause as the mayor and Ms. Weingarten strolled into a press conference at City Hall to herald the new deal.

“Our administration wanted the new contract with the UFT to not only increase teacher salaries, but to also make meaningful changes that will further reform and improve our schools,” Mr. Bloomberg said.

The contract, which struck a balance in recommending changes to both salaries and work rules, is largely based on the nonbinding recommendations issued last month by a state arbitration panel. The union asked the state Public Employment Relations Board to get involved when an impasse was reached at the end of last year. The teachers’ most recent contract expired May 31, 2003.

The new contract would cover four years, four months, and 12 days, one of the longer contracts in the history of union deals. It would expire October 12, 2007.

“We said beforehand, when the fact finder recommendations first came out, that they had a lot of pluses and a lot of minuses. When you look at this agreement, you can see we have turned those minuses into plusses,” Ms. Weingarten said.

The total 15% raise includes a 2% raise effective as of December 1, 2003, a 3.5% raise effective as of December 1, 2004, 5.5% effective November 1 of this year, and 3.25% effective October 1, 2006. By the end of the contract, the starting salary for a teacher would be up to $42,512 from $39,000. The maximum teacher salary would hit $93,416, up from $81,232.

As part of a new program, top teachers can earn an additional $10,000 by opting to transfer to underperforming schools and mentoring the teachers there. With this contract, teacher salaries have increased more than 33% under the Bloomberg administration. Before June 2002, teacher salaries ranged from $31,000 to about $70,000.

“This is a monumental step, one that is crucial to attracting and retaining the highest quality of teachers in our schools,” Ms. Weingarten said about the pay hikes. “And attracting and retaining teachers who are of the highest quality is the key reform in turning around all schools.”

The mayor said the city has already budgeted for the raises for fiscal years 2004 and 2005, but the raises will cost the city an additional $350 million in 2006, $600 million the following year, and $750 million in subsequent years.

“If you want to think about it in business terms, we have decided to go and get a lot more of the product that this system does, which is great education for our kids,” Mr. Bloomberg said

The contract allows principals to interview and hire teachers and assign teachers to hallway and cafeteria patrol. Teachers will now report to school on the Thursday and Friday before Labor Day for professional development. In addition, Brooklyn-Queens Day, which teachers typically had off, will also be used for professional development.

Under the new deal, teachers convicted of sexual conduct with a student would be immediately terminated.

In what Ms. Weingarten called one of the “thorniest” issues between teachers and management, the contract states that teachers can no longer be disciplined for the format of their bulletin boards and classroom furniture arrangements.

“Hopefully it will mean a less contentious relationship, and everybody can focus on learning and teaching,” the chairwoman of the City Council’s Committee on Education, Eva Moskowitz, said.

The mayor said he didn’t think it was fair to call the relationship between his administration and the union “nasty,” and said that he had breakfast with the union president almost every month.

A spokeswoman for Mr. Ferrer, Jen Bluestein, criticized the mayor for dragging his feet.

“The teachers worked hard and waited too long for this contract, and Freddy Ferrer congratulates them on their steadfast service to our kids and their strength in refusing to cave in the face of Mike Bloomberg’s bullying tactics,” she said.

Despite the contract and the hug from Mr. Klein, Ms. Weingarten was not ready to discuss a mayoral endorsement.

“Today is about education, it’s about the teachers and kids and parents,” Ms. Weingarten said. “Today is not a day I want to talk about politics.”