Help!

A shaking steering wheel is typical of a warped brake rotor. There are some things that can happen to cause similar symptoms but that involves removing them. That is not necessary when repairing rusted steel brake lines. If a front rubber hose was replaced, the wheel would have been removed and it's possible a piece of rust or scale fell in between the hub and the rotor which would be loose at the time. That debris will make the rotor sit crooked and wobble as it rotates. That can be felt in the steering wheel, seat, and / or brake pedal.

Your description of the AC problem suggests there might be two different problems. If the fan only works on the fastest speed, the fan resistor that creates the slower speeds might be defective. It is bypassed on the highest speed.

When the air temperature warms up after a few minutes, the system could be low on refrigerant. If the control valve is malfunctioning, it could let too much refrigerant into the heater box and the unit will get too cold. The system is regulated by that valve to prevent the temperature from dropping below about 40 degrees. Humidity in the air condenses on the evaporator and if it gets too cold it will freeze into a block of ice and restrict airflow. What air does come through will be warm until that ice melts.

There are many other potential causes for the symptoms you described. A mechanic will be able to diagnose and repair the problem.