When Sen. Robert J. Dole (R-Kan.) appeared before the Republican National Convention in 1984, he was given a cold shoulder that would have been appropriate for a "tax collector for the welfare state," which is what some conservatives were calling him.

Within months, as Dole took over as Senate majority leader and started laying the groundwork for a presidential bid in 1988, he began an assiduous, behind-the-scenes courtship of the party's right wing that is now moving into full public view.

Only two years after spurning him, many conservatives are hailing Dole for being "right" on the issues, for going out of his way to solicit their views and for expediting Senate consideration of their concerns.

The difference is "overwhelming, almost impossible to describe," said conservative leader Paul M. Weyrich in assessing the starkly contrasting responses that Dole received this year and three years ago in appearances before groups of conservative activists.

But some moderate-to-liberal senators are beginning to complain that Dole's presidential campaign is getting in the way of his leadership of the Senate, and others say it may be affecting the Senate agenda, although probably not the outcome of votes, at least so far.

"Bob Dole, quite frankly, is confusing his duties as majority leader and presidential candidate, and I don't think he can do both," said Sen. Lowell P. Weicker Jr. (R-Conn.), one of the GOP's most liberal lawmakers.

A more moderate Republican senator grumbled that, because of Dole's efforts to accommodate conservatives, the Senate is being forced to grapple with legislation that might otherwise languish on the calendar. One example was legislation brought up in April to extend federal anti-extortion laws to labor violence, said the senator, who asked not to be quoted by name. The measure died in a filibuster, but Dole won points from conservatives for bringing it up.

While Dole has always had a staunchly conservative voting record and a bulging portfolio of public statements to match, his image in recent years has been that of a pragmatic moderate who was not afraid to lead the Republican senatorial majority in a break with party conservatives, including President Reagan. His heresies have always loomed large: willingness to raise taxes, support for civil rights legislation and championship of food stamps and other nutrition programs.

His image as a tough-minded independent force within the Republican Party was reinforced by biting, irreverent quips directed at the White House -- at the president's key advisers, if not the president himself.

But now hardly a week passes without a statement, maneuver or public appearance from Dole that aligns him with party conservatives on issues ranging from abortion and taxes at home to anticommunism abroad. He makes fewer wisecracks about the White House; he has made peace with White House chief of staff Donald T. Regan and curbed his tongue about Defense Secretary Caspar W. Weinberger, both of whom suffered from Dole tongue-lashings about this time last year. He stresses his agreements with the president, not his disagreements.

Just in the past few months, Dole has taken a harder line than Reagan on abandoning the unratified SALT II treaty with the Soviets, sided with Reagan against a majority of his Senate Republican colleagues in opposing tax increases and pushing for more defense spending, issued a barrage of strongly worded statements in support of anti-Sandinista rebels in Nicaragua and played a key role in maneuvering to force covert military aid to Angolan guerrilla leader Jonas Savimbi, a particular favorite of many conservatives.

Only last week he let it be known he was leaning toward support of an amendment to the tax-overhaul bill that would tax nonprofit hospitals, clinics and foundations that finance or perform abortions, even though he earlier came out against any amendments to the Finance Committee's bill.

The amendment was withdrawn after Reagan came out against it, relieving Dole of the burden of making a painful choice on the eve of the National Right to Life Committee convention, which he was to address this weekend.

In most cases, these represent positions that Dole has taken over the years but given little emphasis since assuming a leadership role in the Senate, first as Finance Committee chairman in 1981 and then as majority leader in 1985.

But on issues such as taxes and defense spending, Dole has recently moved closer to Reagan. This has helped Dole shed his image -- earned in earlier budget fights with the White House -- as grand strategist and point-man for congressional GOP rebels seeking to prod the president into more decisive action to reduce deficits, including tax increases and defense spending cutbacks.

Some of his most conservative rhetoric has come in connection with foreign policy and national security issues. Especially in his previous forays into national politics, including his bid for the vice presidency in 1976 as President Gerald R. Ford's running mate, he has nearly always leaned to the right on these issues. But they have not been a major preoccupation for Dole in the Senate, so his recent concentration on them tends to project a different image.

Dole's "outreach" to the right, as a party official called it, has improved his popularity within the conservative movement, according to such key figures as Howard Phillips, chairman of the Conservative Caucus, and Weyrich, national chairman of the Free Congress Political Action Committee.

Phillips and Weyrich said in interviews last week that Dole would be acceptable to many conservatives as a fall-back choice for the GOP nomination. "He wouldn't be their first choice, but he would be acceptable," Weyrich said. "If it's a choice between Vice President Bush and Dole, Dole would be the clear beneficiary of conservative support," Phillips said.

But there are differences of opinion within conservative ranks about Dole, with economic supply-side devotees -- suspicious of his previous willingness to raise taxes -- showing little enthusiasm for him, according to Phillips.

Also, some of those who focus most on abortion and other social issues acknowledge that Dole has voted with them but fault him for insufficient enthusiasm.

"I don't see Bob Dole as somebody who has his heart in any of the issues that conservatives care about," said Phyllis Schlafly, president of the Eagle Forum, in the summer issue of Policy Review, a Heritage Foundation journal. "He is trying to do an effective job as majority leader. But he does not seem to be an issues-oriented person."

In a more typical evaluation, Weyrich, in his Policy Review assessment and in an interview, gave Dole high marks for being "decisive and very tough" and for opening the majority leader's door to the conservative movement, which he said was closed in the days of Dole's predecessor, Howard H. Baker Jr. of Tennessee, another possible contender for the 1988 GOP presidential nomination.

"Dole isn't always in our corner, he doesn't always do what we want, but he is open to us, he listens," Weyrich said.

According to Weyrich and others, Dole decided two years ago he had problems with conservatives and went about correcting them, soliciting their views and sympathizing with their concerns. His problem in the past, said Weyrich, was that "he just hadn't been dealing with the conservative movement."

Dole also has recruited conservatives for important posts in his campaign organization, including former Office of Personnel Management director Donald J. Devine as director of his Campaign America PAC. Devine, in turn, has promoted the proposition that Dole's voting record on issues is as conservative as any of the other potential GOP presidential contenders and that his record of support for Reagan exceeds that of Rep. Jack Kemp (R-N.Y.), a favorite of many conservatives.

Dole speaks proudly of his conservative support, stressing his longstanding right-of-center voting record and balking at suggestions that he is trumpeting his conservativism more and more as 1988 approaches. "What we're trying to do is get properly conservative groups to take a look at our record," he said in an interview.

But Dole's eagerness to assert his conservatism has gotten him in some trouble along the way.

He joined conservative Sen. Jeremiah Denton (R-Ala.) in spearheading legislation to suspend key provisions of the War Powers resolution in cases of terrorism until Denton suggested, almost as an aside, that it might sanction assassinations. Dole's push for the bill slowed markedly after that.

More recently, he dashed out a news release criticizing Reagan for sending "the wrong signal to the Kremlin" in saying late last month he would dismantle two more Poseidon submarines to stay within SALT II limits. When it became apparent that the real decision was to cease compliance with restrictions of the unratified treaty later in the year, Dole made it clear he agreed with Reagan but apparently could not resist adding, "Frankly, I would have done this some time ago."