The Education Department, responding to colleges' complaints about the difficulty of getting some student loan recipients to declare their draft registration status during the summer, has given them until Aug. 31 to meet this requirement.

The extension means an additional month's grace period for the schools, whose financial aid officers have been concerned about the logistical complications of finding students in time to get them to comply by the original July 31 deadline.

On Friday the Senate approved a rider to a defense appropriations bill that would give the colleges until Sept. 30 to comply. A similar extension is pending in the House.

The colleges were put in an unexpected bind by the law's on-again off-again status. A challenge to the 1982 law tying student aid to compliance with draft registration laws was successful in the U.S. District Court in Minnesota. But three weeks after the law was voided, the Supreme Court reinstated it--48 hours before it was supposed to take effect.

The Education Department published guidelines shortly thereafter giving colleges until July 31 to comply in the case of students receiving aid during summer sessions.

Longer extensions were offered for students who would not be returning to campus until fall.