Hydraulic Braking System
Force applied on brake pedal is transmitted to break shoes for its actuation through confined liquid known as "brake fluid". Usually the brake fluid is a mixture Glycerin and Alcohol or Castor oil, Dehydrated alcohol and some additives.The hydraulic brake fluid should passes the following characteristics:t
- It should not soften the rubber parts used Braking System.
- It should not corrode metallic parts used in system.
- It should not vaporized easily.
- It should retain flow at lower temperature.
- It should help for lubrication.
- It should not loose its characteristics easily.
- It should be non compressible.
The hydraulic braking system consists of-
- Master cylinder
- Wheel cylinder
- Brake drum
- Brake shoes
- Brake fluid with brake lines
The master cylinder is connected by tubing two wheel cylinder at each of four wheels. This system is filled with brake fluid under light pressure when brakes are not in operation.
Each wheels consists of a braking drum, which is mounted on inner side of the wheel and revolves with it. to break shoes are mounted inside the brake drum, which does not rotate. The brake shoes are fitted with Heather and wear resisting brake lining on their surface.
The brake pedal is connected to the master cylinder piston by means of Piston rod. For application of brake, driver presses the brake pedal, which moves the Piston in master cylinder, increasing pressure of fluid in master cylinder and in entire hydraulic system. This pressure is instantly transferred to all four wheel cylinders. Piston in wheel cylinder moves outwards moving brake shoes against brake drum to apply brakes.
When driver releases the brake pedal, the master cylinder Piston returns to its original position due to return spring, dropping fluid pressure. Brake shoe retracting spring pulls the brake shoes from brake drum to their original position and brakes are released.
Master cylinder:
The purpose served by Master cylinder is:
To build the hydraulic pressure required to operate the system.
To bleed or force air out of the brake line and wheel cylinder.
To act as reservoir to maintain a constant volume of fluid in system.
