As President Reagan relaxes on his mountaintop ranch northwest of Santa Barbara, tucked away from the workaday cares of Washington, his top advisers have decided to put an end to what one of them calls "unnecessary news stories."

The negative news coverage that the president abhors was a topic of discussion at a White House breakfast the day before Reagan left on his present 25-day trip, the 17th stopover at his ranch since his election.

White House chief of staff James A. Baker III, deputy chief of staff Michael K. Deaver, counselor Edwin Meese III and national security affairs adviser William P. Clark, who rarely see eye to eye on anything, agreed that it would be desirable to put a damper on this "unnecessary news" while Reagan was vacationing.

Their remedy was breathtaking in its simplicity. The Big Four made a pact that they would make themselves unavailable for the usual interviews while Reagan is away from Washington. This is supposed to leave the White House press corps dependent on what might be called the "necessary news stories," namely the pap that White House spokesman Larry Speakes dispenses in the daily briefings at Santa Barbara.

Last week, Speakes managed to make some news attacking media treatment of Reagan's visit to Central America. He also, for the umpteenth time, put the president on record in favor of withdrawal of foreign troops from Lebanon and broke some new ground by having Reagan come out in opposition to hurricanes.

In Washington, the ruling Gang of Four finds it difficult to control the White House staff, not to mention themselves. In Santa Barbara, staff leadership is rotated and control of subordinates more easily achieved because telephones in the hotel rooms of aides are replaced with White House phones whose operators automatically screen media calls.

Deaver, ranking White House official during the first week of captivity in Santa Barbara, set the tone last week by postponing and then canceling on short notice a dinner with reporters. One official who cares for neither Meese nor Clark said he "hoped this would set an example for the rest of them."

White House political adviser Edward J. Rollins has sounded out Henry Cashen, once a deputy to Charles W. Colson in the Nixon administration, about assisting with labor strategy in the Reagan reelection campaign. No final decision has been made, but Cashen is expected to have a role.

Cashen is attorney for the Teamsters union, linchpin of administration efforts to regain the hefty share of the blue-collar vote that carried Reagan to victory in 1980.

The administration will retain close political ties with the Teamsters despite White House counsel Fred F. Fielding's admonitions to the president's top aides to refrain from socializing with Teamsters President Jackie Presser and keep him at "arms length" while he is under investigation by the Labor Department in a union embezzlement case.

Last week in Santa Barbara, a reporter asked Speakes if the administration can continue its relationship with the Teamsters while keeping Presser at arms length.

"It depends on how loud you talk," Speakes responded. Not to mention how long your arms are.

Public liaison director Faith Ryan Whittlesey's recent blast at the media and mainline churches for purported hostility to the administration's Central America policies provoked criticism from many quarters.

Charles Bergstrom, executive director of the Office of Government Affairs for the Lutheran Council, objected to Whittlesey's implied statement that the churches are soft on communism and added: "She's taken an office that could be a forum for exchanging diverse views and turned it into campaign headquarters."

Coming from another direction, the American Legion wasn't happy with credit Whittlesey's shop gave itself for an editorial by the national commander in the Legion magazine comparing Central America to Vietnam. The Legion's G. Michael Schlee points out that the article was sent to the printer a month before Reagan addressed Congress on the subject and well before Whittlesey's office started mobilizing public opinion on Central America.

Disclosure of the Week: (By President Reagan in his speech to the Veterans of Foreign Wars convention in New Orleans): "Well, there really is a River Kwai."

Soon afterward, his speech was followed by what some would call the "plagiarism of the week" when Democratic presidential candidate John Glenn borrowed one of Reagan's favorite presidential campaign lines and declared: "Never again should we send American troops to fight wars we do not intend to win."

This was one of Reagan's biggest applause lines when he appeared before the VFW convention in 1980 and opined that the Vietnam war had been "a noble cause."

Glenn's ability and willingness to appropriate Reagan's themes and phrases did not escape notice among reporters familiar with Reagan campaigns or by a White House that would increasingly like to see the Democrats nominate anyone but Glenn.

Reaganism of the Week: (Speaking to the VFW): "Thank you for that warm greeting and that applause and, since that applause is coming from veterans, I have to ask, is it for how I am doing my job, or how I am doing on the late-late show in 'Hellcats of the Navy'?"