To change the braking effect you edit this line in the aircraft.cfg file:
toe_brakes_scale = 0.885 //Brake scalar
For steering you can change the maximum steering angle:
//0 Class <0=none,1=wheel, 2=scrape, 4=float>
//1 Longitudinal Position (feet)
//2 Lateral Position (feet)
//3 Vertical Position (feet)
//4 Impact Damage Threshold (Feet Per Minute)
//5 Brake Map (0=None, 1=Left, 2=Right)
//6 Wheel Radius (feet)
//7 Steer Angle (degrees)
//8 Static Compression (feet) (0 if rigid)
//9 Max/Static Compression Ratio
//10 Damping Ratio (0=Undamped, 1=Critically Damped)
//11 Extension Time (seconds)
//12 Retraction Time (seconds)
//13 Sound Type
//14 Airspeed limit for retraction (KIAS)
//15 Airspeed that gear gets damage at (KIAS)
For this line:
point.0=1, 40.00, 0.00, -8.40, 1181.1, 0, 1.442, 55.92, 0.6, 2.5, 0.9, 4.0, 4.0, 0, 220.0, 250.0
the steering angle is 55.92 degrees.
If you have other issues with steering, these are usually caused by the landing gear contact point positions, and changing those changes that behavior.
Hope this helps,