knocking noise front wheel after brake job

Go back and recheck all bolts. Make sure they are all secure to proper torque. Vibration in the steering wheel WITHOUT the brake applied may indicate a wheel / tire issue. An out of balance wheel or a defective tire. Rotate your front tires to the rear of the vehicle and road test it to see if it makes a difference.

check your rotors.Might need changing sounds like warped rotor problem