When Common Cause set up its lobbying shop in the Virginia Capital four years ago, legislators looked on it as a pestilence for which the only sure treatment was outspoken disdian.

"You would have to say they are somewhat of a burden when it comes to getting the bill passed," Sen. Adelard L. Brault (D-Fairfax) said in 1975, in the midst of a losing fight for his conflict disclosure bill supported by Common Cause. "They are competent people and the work hard, but unfortunately they evoke a negative emotional response from many Assembly members."

In 1974 and 1975, the organization's only legislative success was the adoption of a rule change by the House of Delegates requiring a public record of committee votes.

But in 1976, a strong lobbying disclosure bill was passed and so was a bill requiring more detailed disclosure of financial interests by Assembly members.

And in the Assembly session just ended, a full dozen bills and resolutions endorsed by Common Cause were approved. Of these, six can be clearly identified as part of the organization's legislative program and the other six, mostly government reorganization measures, were bills that others have developed.

Some of these were proposals that have been kept alive in the Assembly for several years and have simply survived. "You know how it is down there," Brault said. "Ideas are kicked around until they either wear on you or wear out."

One of the bills approved this year is an amendment to the state's freedom of information law that requires all Assembly committee meetings to be open to the public. "When we had a press conference before the Assembly session and announced that the open committee amendment was a part of our program, everyone laughed," said Common Cause lobbyist Judy Goldberg.

However, the bill, sponsored by Rep. James H. Dillard (R-Fairfax), sailed through the House, 84 to 10, and the Senate, 37 to 3. Its approval came despite misgivings among influential members of the budget writing committees of both houses. They have been accustomed to making crucial budget decisions in closed meetings.

The Common Cause successes this year have set off restrained gloating in the organization's spartan offices?near the Capitol.

Among legislators and their aides, there is general acknowledgement that the organization had a good year, but they give only part of the credit to Common Cause.

Many do praise Goldberg for effective lobbying for bills that in past were resented as implications that legislators were deeply involved in personal conflicts of interest.

"She has the right touch," Sen. Joseph V. Gartlan (D-Fairfax), said in an interview. "She doesn't come on too strong and doesn't take inflexible stands."

Gartlan successfully sponsored a bill this year that expanded the number of people required to report potential conflicts of interest. Under Gartlan's bill, most persons appointed by the governor would have to report holdings valued at more than $5,000 among other things. Gartlan is generally perceived as one of the Senate's more liberal members, but most patrons of Common Cause bills this year fall into the moderate-to-conservative category.

The organization's greatest success so far, the major expansion of lobbying reporting, was pushed through by Sen. Frederick T. Gray (D-Chesterfield), one of the Senate's most conservative and most influential members.

Gray took over the legislation after he was named to head a study commission created to review defeated Common Cause proposals.

Gray's sponsorship of the lobbying bill in 1976 and of important amendments to it this year was cited by a legislative staff member as a reason why Common Cause should not be given much credit for the law. "When you have someone like Fred Gray on your bill, you have influence logic and experience no your side, but you can't take credit for it," the staffer said. "He makes up his own mind."

Goldberg worked for no salary until this year, when Common Cause managed to scrape together $1,500 for her services during the session. However, she paid out of her own pocket the cost of caring for her two small children while she spends days and nights at the Assembly sessions.

Other measures passed during the last session with primary backing from Common Cause, include: A bill sponsored by Del, James M. Thomson (D-Alexandria) requiring lawyer legislators to name clients they represent before state agencies and studies of public campaign financing; "sunset" legislation requiring periodic reviews of the need for state agencies, and an examination of regulatory agency-hiring practices to determine the influence of regulated businesses over the agencies.