Secretary of State George P. Shultz's Asian diplomacy was grounded here tonight when his special U.S. Air Force plane broke down on the first leg of his two-week journey.

About three hours after leaving Washington, a 10-pound hydraulic pump on one of the four jet engines cracked, Air Force officials said. The aircraft managed to land here bumpily but safely four hours later.

The Boeing 707 with "United States of America" emblazoned on its side has been ferrying secretaries of state and other high officials around the world for 25 years. It carried a spare hydraulic pump, but once on the ground it was discovered that the pump on another engine had failed.

No other pump to fit the plane could be found on this base and another aircraft had to be dispatched from Washington.

A State Department transportation official said Shultz will be able to leave here for Manila about 4 a.m. Friday Alaska time (9 a.m. Washington time), about 15 hours later than planned. Shultz may have to rearrange meetings with U.S. Embassy officials in Manila, and a luncheon planned with President Ferdinand Marcos may possibly become a dinner, a spokesman said.

Shultz is to meet Marcos in Manila and attend the Association of Southeast Asian Nations foreign ministers' meeting in Bangkok Sunday. After that he is scheduled to visit India and Pakistan, before stopping in London and perhaps the Middle East.