Car keeps bouncing randomly with 'Stabilizer Bars' code

I have no idea what's going on, my car just bounces up dramatically for seemingly no reason when I have this code on:

Code (csharp):

1. public class StabilizerBars : MonoBehaviour {
2.  
3.     WheelCollider FL, FR, BL, BR;
4.     float AntiWheelForce = 200;
5.     public float TravelL = 1.0f;
6.     public float TravelR = 1.0f;
7.     public float AntiRollForce;
8.  
9.     // Use this for initialization
10.     void Start () {
11.         FL = GameObject.Find ("Wheel_FL").GetComponent<WheelCollider>();
12.         FR = GameObject.Find ("Wheel_FR").GetComponent<WheelCollider>();
13.  
14.         BL = GameObject.Find ("Wheel_BL").GetComponent<WheelCollider>();
15.         BR = GameObject.Find ("Wheel_BR").GetComponent<WheelCollider>();
16.     }
17.     // Update is called once per frame
18.     void Update () {
19.         WheelHit hit;
20.         bool GroundL = FL.GetGroundHit(out hit);
21.         bool GroundR = FR.GetGroundHit(out hit);
22.  
23.         if (GroundL) {
24.                         TravelL = (-FL.transform.InverseTransformPoint (hit.point).y - FL.radius) / FL.suspensionDistance;
25.                 }
26.         if (GroundR) {
27.             TravelR = (-FR.transform.InverseTransformPoint(hit.point).y - FR.radius) / FR.suspensionDistance;
28.         }
29.  
30.         AntiRollForce = (TravelL - TravelR) * AntiWheelForce;
31.  
32.  
33.         print (AntiRollForce);
34.  
35.         if (GroundL) {
36.             gameObject.rigidbody.AddForceAtPosition(
37.                 FL.transform.up * -AntiRollForce,
38.                 FL.transform.position);
39.                 }
40.         if (GroundR) {
41.             gameObject.rigidbody.AddForceAtPosition(
42.                 FR.transform.up * AntiRollForce,
43.                 FR.transform.position);
44.         }
45.  
46.     }
47. }

It also doesn't stablize the car at all.
For now it's only enabled for the front wheels. I made it do the back wheels earlier and the same thing happened.
Does anyone know why this happens?

 

Does it work any better if you do it in the FixedUpdate method instead of Update

 

No, it seems to do the same thing.

Edit: Actually, yeah it seems to be doing something now after I apply it to the back wheels as well.
It's still bouncing, though. I can't really tell why it's doing it.

 

I am still having this problem, my car acts exactly as it did without the stabilizers (it easily rolls over), except now it has even less stabilization with the random popping.

I set AntiRollForce to print so I could see what was happening, it stays at values lower than 0.001 and then randomly spikes up to the hundreds. I have no idea what to do.