If the vehicle pulls to the left only while braking, suspect a problem with the front right side brake unit. It's pulling because the left brake unit has more clamping force than the right or opposite brake unit.
A kink in the line, a hose, or a seized caliper results in this problem. A complete visual brake system inspection is in order.
Sometimes, the hose is accidentally twisted when replacing the brake caliper. It's wise to double-check brake work upon completion.