BONN, SEPT. 2 -- Chancellor Helmut Kohl's fractious center-right coalition held together today during a procedural vote in parliament on West Germany's Pershing IA missiles, despite right-wing opposition to Kohl's pledge to dismantle the weapons if a U.S.-Soviet treaty is signed on intermediate-range nuclear forces.

Politicians and other observers said the vote underlined a gradual loss of influence on foreign policy this year by the Christian Social Union, the small, Bavarian-based, conservative sister party of Kohl's Christian Democrats.

The Christian Socialists, led by veteran politician Franz Josef Strauss, have been upset by Kohl's cautious shift away from the right on arms control and Third World topics.

In the most severe break in coalition ranks since Kohl became chancellor in 1982, the Christian Socialists yesterday boycotted the three-party coalition's talks in preparation for today's session. They complained that Kohl's pledge on the Pershings constituted "unilateral disarmament."

But the Christian Socialists' cooperation with the chancellor in today's procedural ballot made clear that they are unwilling to trigger a major political crisis. They voted with the Christian Democrats and the centrist Free Democrats, the third coalition partner, to refer to committee an opposition resolution designed to bring into the open the policy rift within the coalition.

As a result, Kohl's pledge on the Pershings was viewed here as firm, even though he technically does not have an endorsement for it either from parliament or his Cabinet because of the Christian Socialists' opposition. An important factor bolstering Kohl was a poll showing that 86 percent of the population supports his decision.

"For a long time now, Kohl has seen his Munich adversary {Strauss} as an aging paper lion. And he is not wrong this time either," the independent daily Sueddeutsche Zeitung said.

Kohl announced a week ago that West Germany would dismantle its 72 intermediate-range Pershing IA missiles if the two superpowers scrapped their own intermediate-range weapons as foreseen under the proposed treaty.

Kohl's move appeared to remove a major obstacle to the treaty, although the Soviets have said since then that the United States must agree to dismantle the U.S.-controlled warheads on the Pershing IAs. Moscow also is demanding that the warheads be included as part of the treaty, while Washington refuses to do so on grounds that the proposed accord is a bilateral, U.S.-Soviet pact and therefore cannot affect West German weapons systems.

West German officials said that Bonn has done as much as it can to facilitate an arms control agreement, and it is now up to the United States to overcome the remaining differences with the Soviets.

The Christian Socialists and conservatives in Kohl's own Christian Democratic Union have had to back down repeatedly this year on foreign policy issues. Kohl has been steering the coalition toward the center under the guidance of Free Democratic Foreign Minister Hans-Dietrich Genscher, and Christian Democratic party secretary Heiner Geissler.

A major reason has been the Free Democrats' repeated advances at the polls, beginning with their gains in January's national election. The Christian Democrats had a surprisingly weak showing in that election, and the results were widely interpreted as a signal from the electorate to embrace Genscher's detente-oriented policies.

In June, Kohl rebuffed the conservatives after a bitter fight when he endorsed a broadening of the proposed arms control pact to include an extra class of missiles.

Then, a new dispute arose over whether Bonn should give asylum to 14 Chilean prisoners who faced the death penalty. The issue is still unresolved.