Takoma Park, which for seven years has steadfastly refused to do business with companies involved in the manufacture of nuclear weapons, is on the verge of straying from that policy -- if only for a month.

The City Council is scheduled to discuss tonight whether to buy three police cars and two trucks from Ford Motor Co., which has a nuclear weapons division, but is expected to sell it next month. If approved, the purchases would be the first of their kind since Takoma Park declared itself in 1983 one of the nation's few nuclear-free zones and halted business with companies dealing in nuclear weapons.

City officials say that while Takoma Park is still committed to the unusual anti-nuclear policy, an exception should be made in this case because the city needs the vehicles and Ford appears ready to leave the weapons business.

"The company is moving in a positive direction," said Mayor Stephen J. Del Giudice, noting that buying from a company that is selling its nuclear interests sends a good message.

The possible deal with Ford comes with the blessing of the city's Nuclear-Free Zone Committee, which said that Ford is one of only two companies assembling police cruisers and that it manufactures the trucks best suited to Takoma Park's leaf collection and snow removal programs. Advocates say the proposed deal with Ford would be in keeping with a 1985 amendment to the law permitting business between the city and nuclear weapons makers if there is no alternative.

Nationally, said City Council member Hank Prensky, nine jurisdictions including Berkeley, Calif., Amherst, Mass., and Jersey City, N.J., maintain an anti-nuclear purchasing policy similar to that of Takoma Park.

Prensky, who is also a member of the Nuclear-Free Zone Committee, said a waiver would not weaken the law and that all of the city's needs must be considered in the proposed purchase.

"My job as a council member is to protect the health and safety" of the community and police officers, said Prensky.

But, there are some who question the timing of the waiver and believe the city has not explored all options.

Jay Levy, who in 1983 helped bring the original nuclear-free zone proposal before the council, said that before city officials agree to a waiver, they should consider buying motorbikes or bicycles for the police, or renting special trailers to collect the leaves.

"The intent {of the law} is not to cooperate with the nuclear destruction machine," Levy said. "There is no reason the city can't continue to avoid it. Why not just wait a few weeks?"

Levy said he and other members of the Takoma Park Peace Task Force will speak at tonight's public hearing to urge the council not to let any money change hands with Ford until the company sells its Ford Aerospace branch, expected in October.

Prensky this past weekend began work on a proposal urging the City Council to grant the exception to the nuclear-free law tonight and purchase the vehicles from Ford. But, according to the plan, if Ford sells its Ford Aerospace division as expected to the Loral Corp. of New York, the waiver at that point would become unnecessary and be wiped from the city's books.

Levy said such a plan could meet with the approval of his group, only if the city agrees not to pay Ford until the company's nuclear divestment is complete.