race gui button doesnt work

i am developing 3D rickshaw racing android game.when i press race button works fine and after brake button press works fine and after pressing brake button press race button doesn't work.these are GUI button made in code in C#. using UnityEngine; using System.Collections;

public class GUI_button : MonoBehaviour {

 public GameObject RickFULL;

 //intialization for Sound tracks Obj
 public GameObject race_paddle_snd;
 public GameObject brake_paddle_snd;


 //initailization for the GUI Button
 public Texture2D race_paddle_texture= null;
 public Texture2D brake_paddle_texcture = null;
 public Texture2D Back_to_Menu_texture = null;

 public GUIStyle race_paddle_style = null;
 public GUIStyle brake_paddle_style = null;
 public GUIStyle Back_to_Menu_style = null;

 bool Back_to_Menu_pressed = false ;



 Rect race_paddle_texture_pos = new Rect(Screen.width - 100, Screen.height - 130, 100, 100);
 Rect brake_paddle_texture_pos = new Rect(Screen.width- 1200, Screen.height -130 ,100,100);
 Rect Back_to_Menu_texture_pos = new Rect(Screen.width - 100, 20 ,70,40);

 //Intialization for the Wheel Collider
 public GameObject wheel_front_collider;
 public GameObject wheel_back_left_collider;
 public GameObject wheel_back_right_collider;
 float fmaxTorque = 3000.0f;

 //initialization for the wheels transform rotation
 public GameObject wheel_front_transform;
 public GameObject wheel_back_left_transform;
 public GameObject wheel_back_right_transform;




 //intialization for steer Handling Speed
 float lowest_steer_at_speed= 50.0f;
 float lowest_speed_steer_angle = 10.0f;
 float highest_speed_steer_angle = 01.0f;
 float deaccelerationSpeed =200000.0f;        //Decreasing the acceleration in case the race is not pressed


 Vector3 deltaVect3 = new Vector3 (0,0,0);
 float deltaAng;

 //GUI Function body Intailization
 bool race_button_pressed = false;
 bool brake_button_pressed = false;
 //void race_button_pressed();
 //void brake_button_pressed();


 void AccelerometerMove()
 {
     float x = 0.0f;
     x = Input.acceleration.x;
     //current_steer_angle = y;

     //Debug.Log ("X = " + x);
     wheel_front_collider.GetComponent<WheelCollider> ().steerAngle = 100 * x;//current_steer_angle;

     if(race_button_pressed==true)
     {
         wheel_back_right_collider.GetComponent<WheelCollider> ().motorTorque = -fmaxTorque;
         wheel_back_left_collider.GetComponent<WheelCollider> ().motorTorque = -fmaxTorque;
         race_paddle_snd.SetActive (true);
         Debug.Log ("race_button_pressed");
         //race_button_pressed = false;
     }

     else 
     {
         wheel_back_left_collider.GetComponent<WheelCollider> ().motorTorque = 0.0f;
         wheel_back_right_collider.GetComponent<WheelCollider> ().motorTorque = 0.0f;
         race_paddle_snd.SetActive (false);
     }





     if (brake_button_pressed == true) {
         wheel_back_right_collider.GetComponent<WheelCollider> ().brakeTorque = deaccelerationSpeed;
         wheel_back_left_collider.GetComponent<WheelCollider> ().brakeTorque = deaccelerationSpeed;    
         brake_paddle_snd.SetActive (true);
         Debug.Log ("brake_button_pressed");
     }
     else 
     {
         brake_paddle_snd.SetActive (false);    
     }

} void FixedUpdate() { AccelerometerMove (); }

 void Update()
 {
     //start---> Rotaion of wheels
     wheel_back_left_transform.GetComponent<Transform> ().Rotate (wheel_back_left_collider.GetComponent<WheelCollider>().rpm/60*360*Time.deltaTime,0,0);
     wheel_back_right_transform.GetComponent<Transform> ().Rotate (wheel_back_right_collider.GetComponent<WheelCollider>().rpm/60*360*Time.deltaTime,0,0);


     //start---> Steer Angle of front Wheel

     deltaAng = (wheel_front_collider.GetComponent<WheelCollider>().steerAngle)-(wheel_front_transform.GetComponent<Transform>().localEulerAngles.z);
     deltaVect3.Set (0,deltaAng,0);

     wheel_front_transform.GetComponent<Transform> ().Rotate (wheel_front_collider.GetComponent<WheelCollider>().rpm/60*360*Time.deltaTime,deltaAng,0);
     wheel_front_transform.GetComponent<Transform> ().localEulerAngles = deltaVect3;

 }
 void Start()
 {
     RickFULL.GetComponent<Rigidbody> ().centerOfMass = new Vector3(0,-2,0);
     race_paddle_snd.SetActive (false);
     brake_paddle_snd.SetActive (false);    
     //Back_to_Menu_pressed = false;


 }




 private void OnGUI()
 {

     if (GUI.RepeatButton (race_paddle_texture_pos, race_paddle_texture,race_paddle_style))
     {
         race_button_pressed = true;
     }
     else
     {
         race_button_pressed = false;
     }

     if (GUI.RepeatButton (brake_paddle_texture_pos, brake_paddle_texcture,brake_paddle_style)) {
         brake_button_pressed = true;
     } else {
         brake_button_pressed = false;
     }



     if (GUI.Button (Back_to_Menu_texture_pos, Back_to_Menu_texture,Back_to_Menu_style)) 
     {
         //Back_to_Menu_pressed = true;
         Application.LoadLevel ("menu");
         //(GUI.Button (Back_to_Menu_texture_pos, Back_to_Menu_texture)) = false;
         Debug.Log("Back_to_Menu_pressed = true");
     }

 }

 }