Gov. John A. Volpe has acted to break the deadlock over the relocation of the Bennett St. MBTA yards which has held up construction of the John F. Kennedy Memorial Library for three years.

Volpe said at a press conference yesterday that he will send a special message to the General Court (state legislature) within a week suggesting that the yards be moved to a marshy area near Butler St. on the Milton-Dorchester line so that the Library can occupy the vacated Bennett St. site.

The message will also recommend authorizing the MBTA to float a $4 million loan to finance the new yards.

This means that construction of the Library will be completed, at the soonest, in mid-1973.

It is impossible to say now when--or even if--the proposed legislation will be enacted, a Volpe spokesman said last night.

But, as soon as the bill does become law, it will take one and one-half to two years to complete the relocation of the transit facilities, according to both Kennedy Library and MBTA officials.

A year later, the Library official said, the first part of the 12-acre complex will be opened.

An outcry against Volpe's proposed site seems to have already begun. Arthur G. Coffey, director of administrative service for Boston, said the city would be opposed to locating the yards in Dorchester. "I'm certain there are other sites available," he said in a newspaper report yesterday.

And Francis Brooks, chairman of the Milton Board of Selectmen, protested that state and MBTA officials were going ahead with their plans without providing the town with detailed information, the same source reported.

Volpe's message has been interpreted as a reaction to a report Tuesday night that the Kennedys were considering moving the Library to Washington, D.C.

But Volpe's press secretary said yesterday that "the Governor never even saw that report."

Legislative Commitment

Since he took office, Volpe has repeatedly spoken of a "moral commitment" to the construction of the Library in Cambridge. But now, by making a legislative commitment as well, Volpe is "taking the ball and running with it," in the words of a Library official.

The Library has been plagued with problems ever since it was first conceived in March, 1964. Despite initial successes in raising money and getting the state to pay for the Bennett St. yard land, things have bogged down.

After a long search to find a place to relocate the Cambridge transit facilities, MBTA officials settled on a 15-acre site in Dorchester near Codman Sq. The relocation was intended to be only temporary, and plans provided that an unsightly car-washing machine be well hidden.