The Senate yesterday failed, for the fourth time, to break a filibuster holding up two sweeping anti-busing amendments.

The attempt to invoke cloture against the filibuster led by Sen. Lowell P. Weicker Jr. (R-Conn.) fell three votes short, 57 to 33, as several supporters failed to show up. Under Senate rules 60 votes are required for cloture.

Within an hour of the vote, a fifth motion for cloture was filed by Minority Leader Robert C. Byrd (D-W.Va.) and a vote was scheduled for Wednesday. Weicker, who began his filibuster in June, said, "I wouldn't want to predict how that vote will turn out."

But the Connecticut Republican pledged to continue delaying tactics "as long as we're going to have this type of social issues which are the pet projects of the far right coming to the Senate floor."

Sen. Jesse Helms (R-N.C.) is the author of an amendment to a Justice Department appropiations bill that would bar the department from taking part in suits that might "directly or indirectly" result in court orders to bus students for racial integration.

Sen. J. Bennett Johnston (D-La.) is sponsor of an even farther-reaching proposal to restrict federal courts from busing students more than five miles or 15 minutes driving time from their homes. It would also allow the attorney general to file suits in behalf of students who have been bused beyond these limits.