After any operation that disconnected the power steering lines, the power steering system must be bled of air.
Raise the front of the vehicle and secure it on stands.
Rotate the front wheels from lock to lock several times. Check the fluid level in the power steering reservoir and if it is low, add fluid. Repeat this work until the liquid level on the dipstick stops dropping.
Start the engine and let it run at fast idle. Recheck the fluid level and top up if necessary.
Remove air from the system by turning the wheels left and right without stopping. Be careful not to bleed the system when the tank is empty.
Once the system has been bled of air, turn the wheels straight ahead and run the engine for a few more minutes before stopping it.
Carry out a test drive to ensure that the steering system operates normally and is not noisy.
Again check the fluid level, which, when the engine is warmed up to normal operating temperature, should be near the upper mark on the dipstick, and add fluid if necessary.