Two Billings men Friday admitted they conspired to overcharge Thrifty Car Rental customers and insurance companies for cracked windshields and to split profits from the scheme.

Jeffrey R. Loney, 51, who was fleet manager at Thrifty, and Kevin J. Massick, 47, who owned Fas-Break Windshield Repair, each pleaded guilty in federal court to conspiracy to commit mail and wire fraud. They have agreed to cooperate with the government in return for possible sentence reductions. In return, prosecutors agreed not to file additional charges.

A third defendant, Michael W. Ryan, 35, of Billings, has pleaded not guilty to a 17-count indictment charging him with conspiracy and numerous fraud counts. Ryan owned Thrifty Car Rental.

The business was sold to Lewis Transportation, headquartered in Salt Lake City, in April. The current owner has cooperated with the investigation, authorities said.

Assistant U.S. Attorney Eric Wolff said that from the summer of 1999 until January 2003, when FBI agents executed search warrants at the businesses, Loney and Massick conspired to overcharge Thrifty customers and insurers for windshield damage.

Customers returning vehicles with any windshield damage, including minor nicks and chips, were told that the windshield had to be replaced. Fas-Break prepared invoices, frequently for more than $1,000, showing replacement of the windshield, when in numerous cases the windshield was not replaced, and chip repairs were done for $25.

In one instance, a man from Michigan man rented a minivan from Thrifty in 2002 to take his family on a tour of Yellowstone and Grand Teton national parks. When he returned the vehicle, he noticed a chip smaller than the head of a pencil eraser. The man was told that the windshield had to be replaced; he protested but eventually gave in, Wolff said.

Fas-Break sent an invoice to the Michigan's man insurance company saying the windshield had been replaced for $1,506. The insurance company sent a check to Thrifty Car Rental for $1,406, which was the amount minus the deductible.

Wolff said there is no evidence that that the minivan's windshield was ever replaced at Fas-Break. Evidence showed that three other Thrifty customers were cited for windshield chips and had to pay for windshield replacements on the same vehicle. There is no evidence Fas-Break performed the replacements, he said.

The investigation shows that ''well over 100 customers or their insurers'' paid for purported windshields replacements at Fas-Break that never occurred, Wolff said.

The men boasted about the scheme to others, he said.

Loney and Massick disputed that the scheme involved more than 100 customers, saying the number has yet to be determined.