An arbitration board yesterday reduced the penalties Metro had imposed on four men active in the seven-day wildcat transit strike last July from firings to suspensions without pay ranging from four to eight months.

Metro lacked sufficient cause to fire the men, the board ruled, largely because such harsh penalties had never been imposed by Metro in similar illegal wildcat strikes in the past.

In the future, however, arbitration board chairman William Feldesman wrote, if any of the four strikers encourage or participate in another illegal strike, they can be unqualifiedly discharged.

The four men involed - Eugene Ray, Michael Golash, Gary Alan Young and George Goodwin - played highly visible leadership roles at one time or another during the strike, which shut down both the bus and subway systems here.

Ray, a bus driver assigned to the Four Mile Run Division in South Arlington, assumed the role of strike leader about halfway through the incident. He was assessed the eight-month suspension, the most severe penalty imposed. He would not be permitted to return to work before April 2, 1979.

Golash, a bus driver in the Northern Division, was suspended for six months; Young, a subway mechanic, was suspended for five months, and Goodwin, also a subway mechanic, was suspended for fourth months.

Metro officials had been particularly anxious to make some of the firings stick as they were appealed through the grievance procedures provided by the union contract.

Metro general manager Theodore C. Lutz said yesterday that he was "concerned that the decision support future management actions." The findings he said, was a "good one" to the extent that firing was held out as a real possibility in the case of future strikes.

The suspensions - particulary Ray's for eight months - are regarded as unusually harsh.

Rodney Richmond, secretary-treasurer of Local 689 of the Amalgamated Transit Union, said, "We're happy with the decision . . . We're glad to get 'em back."

Some high-ranking union leaders are known to have hoped quietly that the firings would stick in some cases. The union publicly attempted to end the strike but clearly had no control of its membership during the strike. It could not be learned yesterday whether the four men intend to return to Metro.

The arbitration board found that Metro had never before fired anyone as the result of a strike and that it moved unevenly against strikers in the case. One striking driver, the late William Scoggin, was clearly a strike leader early, but also clearly led a back-to-work movement in Arlington. Metro never moved against him.

Metro, Feldesman wrote, never told employes "that unlawful strikes would be taken seriously and employes guilty of such misconduct dealt with severely."

Metro fired 10 employes as a result of the strike; three have already returned to work under negotiated agreements; two cases remain in arbitration; and one discharged employe has remained just that. He did not appeal.