Breaks

Both front brakes?

Brakes hoses can block fluid return when they go bad, you've replaced one but still have another 3 that may be suspect. You also might have a steel line that can also be bad, when they rust they can shrink interior diameter, even a rusty clamp can cause compression on the line. But usually when all 4 brakes are locking up it's the master cylinder. If you had a shop do this have them look over their work. not only does a MC need to be bench bled the ABS distribution block should be cycled to ensure no air is trapped in system.