A dramatic revision of the Hatch Act, which would free federal workers to run for office, support political parties and raise money for candidates on their own time, is on a fast track in the House with the support of all but one of the 22 members Post Office and Civil Service Committee.

The bill, sponsored by Rep. William L. Clay (D-Mo.), prohibits political activities while civil servants are on duty, in federal buildings or vehicles or in uniform. But it would allow federal employes to engage in any legal political activity off the job, according to Clay, and would prohibit supervisors from pressuring subordinates to participate or contribute.

A spokesman for Constance Horner, director of the Office of Personnel Management, said the administration is studying the bill. Horner testified in June that a similiar bill would politicize the federal government "to an extent unprecedented in recent American history."

The extent of Senate support for the measure is uncertain. But testimony from witnesses during hearings this summer on two earlier, similar bills suggested that the furor that arose when Democrats tried to revise the act 11 years ago will not be repeated.

"I think it's time that some revisions should be made in all fairness to federal employes," said Rep. Gene Taylor (R-Mo.), ranking minority member of the committee. He said both House Minority Leader Robert H. Michel (R-Ill.) and Minority Whip Trent Lott (R-Miss.) favor revising the Hatch Act, which bars civil servants from most partisan political activity.

The bill is scheduled to be reported out of the committee Tuesday, but Taylor said he has asked Chairman William D. Ford (D-Mich.) for time to try to reach a consensus with the administration.

The Hatch Act was passed in 1939 in part to prevent the Democrats from using their public jobs to extract political contributions. The sticking point in previous revision attempts has been how to protect workers who do not wish to participate in politics or in a particular political campaign from being coerced into doing so.

Clay's bill would prohibit federal employes from giving, receiving or soliciting political contributions "from or to a superior." Federal employes also would be barred from accepting political contributions from contractors or industries that are regulated by the employe's agency.

Clay's bill had 126 sponsors when it was introduced Thursday. It covers both civil servants and postal workers.

"Three million federal and postal employes have been improperly and unconscionably denied the ability to participate in the political process," Clay said in a statement. "The broad support this legislation enjoys. . . is a significant breakthrough."

Some people object to revising the Hatch Act for fear it would turn the 2.1 million civil servants and 800,000 postal workers into an action arm of the Democratic Party. "Probably most of them are Democrats," Taylor laughed, "and I may be hurting my own cause."

"I think you must assume some opposition," he said, "but when people think it through, I think they will realize that {the Hatch Act} is just not fair."