Libya and Saudi Arabia, the most radical and the most conservative of the Arab states, announced today that they are restoring diplomatic relations, which were broken off 14 months ago over a Saudi decision to seek U.S. air protection from the Iranian-Iraqi war.

The surprise reconciliation between the two heretofore bitter foes is one of a number of Arab moves aimed at mending many feuds to deal more effectively with the Israeli annexation of Syria's Golan Heights.

A statement issued simultaneously by the Saudi and Libyan governments said the decision had been made to "heal the rifts in Arab relations and unify Arab action against the common enemy."

The Israeli action has sent shock waves through the badly fragmented Arab world and provoked the start of rapprochements between a number of estranged conservative and radical states that could result in an emergency summit in January to adopt a joint strategy.

President Hafez Assad of Syria, whose opposition to a Saudi peace plan for the Middle East caused the breakup of the latest Arab summit in Morocco five weeks ago, has just returned from an apparently successful fence-mending visit to Saudi Arabia. Assad met in Damascus today with an Iranian delegation headed by Foreign Minister Ali Akbar Vellayati.

State-run Syrian Radio issued a veiled call for Iraq to end the war with Iran, Reuter reported from Damascus. The commentary recommended that all Arab energies should be directed against Israel and urged "those who have been preoccupied with other artificial battles" to stop them immediately .

There are reports that Iraq and Libya, which also broke ties over the Iraqi-Iranian war, may shortly announce the resumption of diplomatic relations. Libya, although an Arab state, has sided with non-Arab Iran.

Meanwhile, fresh diplomatic efforts, involving Syria, Saudi Arabia and Kuwait as go-betweens, have begun to find a way for both Iran and Iraq to join in a united front against Israel.

There are doubts that this latest attempt to end the 15-month-old war will succeed, where a dozen others by various Third World and U.N. mediators have failed. But it is clear that the Arab world generally feels under enormous pressure now from Israel and wants to put its house in order and take countermeasures, which may be aimed as much against Washington as Tel Aviv.

No Arab leader is talking about launching a war in retaliation for Israel's annexation of the Golan Heights. Instead, an emergency summit, if it is held, is expected to consider diplomatic and possibly economic pressure on Washington to get Israel to rescind its action.

The sudden resumption of relations between Libya and Saudi Arabia came after months of feuding, mainly over the close Saudi political and military relationship with the United States.

Libyan leader Muammar Qaddafi bitterly attacked the Saudi decision to ask Washington for radar surveillance planes to help defend against possible Iranian attack after the onset of the Iranian-Iraqi war in September 1980.

Qaddafi called the presence of the U.S. planes in Saudi Arabia a "desecration" of the holy Islamic sites in Mecca and Medina and called for a holy campaign to "liberate the house of God."

Saudi King Khalid, in turn, accused Qaddafi of joining Israel, "the enemy of Islam and the Moslems," and of becoming "a spearhead against Islam and its sanctuaries."

Except for a pro-forma Saudi declaration of support for Libya when the United States shot down two Libyan planes over the Gulf of Sidra last August, the two countries have not had a good word to say to each other since the rupture of relations in October 1980.

It is still not clear whether the two will exchange ambassadors or simply reopen their embassies. Equally unclear is how far Saudi Arabia is prepared to go at this time in behalf of Syria.

The Saudi government was furious with the Syrians after they joined the Libyans in thwarting the eight-point peace plan of Crown Prince Fahd at the Arab summit in Morocco. Nevertheless, a statement issued by Fahd at the time of Assad's visit to Saudi Arabia seemed to give strong Saudi backing to the Syrian leader, including a hint at the use of Arab armed forces to try to get the Golan Heights back.

If "there was no other solution, then the territory would be recovered in the same way it was seized," Fahd said. But Fahd stressed the need first for Arab consultation to consider "the most appropriate means" to respond to the Israeli annexation.

Nothing was said at the time about Syrian support for the Fahd peace plan. But there has been speculation in the Arab press ever since Assad's trip that the quid pro quo for Saudi backing of Syria over the Golan will be Syrian acceptance of the Fahd plan when Arab leaders resume their suspended summit conference in Fez in April.