Something not right there car was flat coming In no need to brake as open road ahead looks like a fault with the rear brakes as they lock up before the fronts
Yup - brake bias.
It does take a while to get it right if you have adjustment. When I did away with the ABS on the 97 Trans Am I had to install a proportioning valve to set the brake bias as previously the ABS module did that.
It took me a while and a bit of testing to get it right by the seat-of-the-pants-ometer. Then the MOT machine showed brake effectiveness and I had it virtually right.