I haven't made a car in unity yet, but from what I read in the docs you should use Brake Torque for braking. Something like this maybe->

var brakeButton : String = "MyInputBrakeButtonName" ; 
var brakePower : float = 100.0 ;
 
//in update() with your other stuff->
   if(Input.GetButton(brakeButton)){
      FLWheel.brakeTorque = brakePower ;
      FRWheel.brakeTorque = brakePower ;
   }

Note: you're only going to have front brakes like that lol

That never even crossed my mind... Thanks:) Will that solve the rolling do you think?

One last question, now that I've got that all sorted out, thank you:), I'm not sure how to make a brake system. Simply pressing reverse takes forever to slow it down. I figure I have to alter the velocity in some way but have no idea how...

Here's my code:

var FLWheel : WheelCollider;
var FRWheel : WheelCollider;
var maxForwardSpeed : float= 50.0;
var maxReverseSpeed : float= 50.0;
var turnRadius : float= 30.0;
var EngineTorque : float = 25;


function Start () {
rigidbody.centerOfMass += Vector3(0, -.5, 0);
}

function Update () {


    /*Apply forward motion (Torque) to the front wheels*/
    FLWheel.motorTorque = -EngineTorque * 10 * Input.GetAxis("Vertical");
    FRWheel.motorTorque = -EngineTorque * 10 * Input.GetAxis("Vertical");

    /*This limits the car to a max speed. It is negative because the input for up and down
    are reversed for whatever reason*/

    if(FLWheel.motorTorque && FRWheel.motorTorque < maxForwardSpeed){

    FLWheel.motorTorque = -maxForwardSpeed;
    FRWheel.motorTorque = -maxForwardSpeed;

    }

    /*This limits the car to a max speed when travelling in reverse. Horizontal input is correct,
    so no negatives need to be put in place.*/
    if(FLWheel.motorTorque && FRWheel.motorTorque > maxReverseSpeed){

    FLWheel.motorTorque = maxReverseSpeed;
    FRWheel.motorTorque = maxReverseSpeed;

    }

/*Turn Radius variable increases or decreases the tightness of the turn*/
FLWheel.steerAngle = turnRadius * Input.GetAxis("Horizontal");
FRWheel.steerAngle = turnRadius * Input.GetAxis("Horizontal");

rigidbody.constraints = RigidbodyConstraints.FreezeRotationX;
rigidbody.constraints = RigidbodyConstraints.FreezePositionY;

}