The Arlington County Board, acting almost a month after its plans to fire County Manager W. Vernon Ford were revealed, has voted 3 to 2 to relieve him of the county government's top position.

Ford, 51, formally was suspended by the board late Tuesday night from his $59,000-a-year position. Under Virginia law, he has 30 days to ask for a hearing on his dismissal. After then, the board must vote again to make his discharge final.

"Even if he wanted a hearing, it would not make any difference," said Arlington Board Chairman Stephen H. Detwiler yesterday. Detwiler said Ford, who has headed the county government since 1976, had lost the confidence of the board's three Republican members, who joined him in the vote to oust Ford.

"I would not attempt to make a list of the two or three actions or instances which may have caused me to" seek Ford's firing, Detwiler said. He added that Ford had been a disappointment in implementing the board's policy.

Board member Ellen M. Bozman, an independent who joined Democrat John Milliken in opposing the firing, said she saw the issue differently. "The whole scenario has been outlandish. This is a dreadful way to run a business," she said yesterday. "People ought to be very disturbed about how the process was handled."

Milliken agreed. "It demeans and ignores the basic principles that have served Arlington so well: openness, participation, debate, dialogue and respect for the competence and professionalism of the civil servants."

Ford left yesterday on a long-planned trip to China, has been on leave and unavailable for comment since the board's three GOP members decided Aug. 6 to oust him. That decision, made in executive session, was revealed the next day by Milliken and Bozman.

Ford's attorney, Duane W. Beckhorn, said yesterday that no decision has been made on whether Ford, a county employe 22 years, will seek a public hearing. Beckhorn said Ford will not return to Arlington until Sept. 25 and that he is still negotiating with Earl E. Shaffer, a special board-appointed lawyer, on a settlement for Ford on such issues as severance pay and his pension.

Detwiler said he will ask the board Sept. 12 to consider appointment of a committee to consult on criteria for a new county manager.