That looks like a male flare fitting would seat correctly, Try a 1/4" male flare fitting and the other end can be inverted flare to accommodate the brake line.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy