The leadership of the International Brotherhood of Teamsters strengthened its position today by winning constitutional changes that could restrict dissent within the union and that will boost by as much as 60 percent the salaries of the union's top leaders.

Under the amendments approved today, the straight annual salary of the union's general president will rise about 40 percent, from $156,250 to $225,000; and the yearly pay of the union's second-in-command, the general secretary-treasurer, will rise about 60 percent, from $125,000 to $200,000.

The new salary schedules mean that the president of the Teamsters Union, the nation's largest, will continue to receive the highest pay of any union president in the United States.

The constitution and bylaws changes were made in delegate voting on the second day of the Teamsters 22nd constitutional convention, which is held every five years.

The loyalty oath provision requiring that Teamster members "not divulge to non-members the private business of the union; unless authorized to do the same," passed on an overwhelming voice vote. It came one day after the union approved a related resolution condemning alleged "media abuses" and rebuking the "chronic, excessive arrogance" of the press.

However, the greatly outnumbered dissident delegates to the convention said today that the loyalty amendment will do more than act as a kind of official gag order on potentially talkative Teamsters.

It is a message to would-be dissidents "that they not get out of line," said Ken Paff, a spokesman for the tiny, rebel "Teamsters for a Democratic Union."

The loyalty provision also requires that each union member "pledges his honor: to faithfully observe the constitution and laws of the International Brotherhood of Teamsters . . ." and to "conduct himself or herself at all times in such a manner as not to bring reproach upon the union."

The good conduct portion of the loyalty provision was backed whole-heartedly by the union leaders, including interim Teamster General President Roy L. Williams, who is under federal indictment for allegedly conspiring to bribe a member of the U.S. Senate. Williams, who took over the union's reins after the death May 6 of Teamsters General President Frank E. Fitzsimmons, has vigorously denied the charge.

Williams is expected to be elected here this week to lead the union for the next five years. He faces token, but vocal, opposition from Peter Camarata, a warehouse worker from Detroit who is the TDU presidential candidate.

In other action today, the union approved a change deleting from its constitution a provision that said: "The officers of the international union shall as nearly as practicable be uniformly distributed throughout the entire jurisdiction of this international union."

The proposal to delete was initially opposed by mamy on the convention floor who argued that it would concentrate power in a few key conferences. But the proposal was finally pushed through by Williams.

The convention also created a formal line of succession in the case of the death, resignation, or removal of the union's general president from office. This was considered necessary because they had no succession mechanism when Fitzsimmons died. Under the new arrangement, the secretary-treasurery will immediately assume the president's duties until a president is elected by the union's executive board.