Vehicle Braking Systems: Components and Maintenance
**Friction**
Friction is the resistance presented by the road surface to the displacement of the vehicle. There are two variables that act directly: the road surface and tire tread.
**Speed**
Speed is the distance traveled by a vehicle at a certain time and immediately determines the speed and reaction time. To move through high-speed, low-profile tires need to absorb the difference in height and remain glued to the road.
**Stopping Distance**
Stopping distance is the minimum distance a vehicle needs to stop. What determines the braking is the mass and speed.
**Kinetic Energy**
Kinetic energy is the energy that builds up when the vehicle is in motion and tends to keep it moving, contrary to the braking system.
**Weight**
This variable is ruled by law that always indicates the maximum load is 7 tons and two tons for a twofold axis. To protect the roads, the maximum weight, including each load, should not exceed 45 tons to protect bridges. Heavy weight is determined by weighing the truck on a Roman scale.
**Mechanical Brakes**
Mechanical brakes are based on the law of levers. Brake systems were used in chariots during races; you need to lower the speed to produce sharp corners. A fully integrated system for timber appeared, which was operated with a crank outside the wheel, and its coefficient rise is poor. After, the timber was changed by leather, improving braking.
**Parking Brake**
**Function**
The parking brake is responsible for stopping the car when it is completely stopped before you can park it.
**Component Parts**
The parking brake operation can be manual or foot-operated. The force is transmitted via a lanyard to a beam that travels the lining when the drum pressure and slows the vehicle.
**Maintenance of the Parking Brake**
The rope in vintage vehicles is reviewed and then is withdrawn. In case of fatigue of the rope material, it should be changed to a new lanyard. The lanyard must be changed when it reaches the ceiling.
**Parking Brake Control**
To regulate it, you must remove the rear wheel drum brake shoes and wash all components with methylated spirits if they are very dirty. Then you must get under the car to adjust the rope and adjust its position.
**Brake Pump**
**Function**
The brake pump is responsible for slowing down the vehicle as desired by the driver. In the braking position, when pressing the brake pedal, the force is transmitted to all or the piston rod through the rubber or primary pressure. This closes the orifice of the pressure compensation, raises the liquid, and opens the check valve from the liquid to the cylinders, stopping the vehicle.
**Brake Release Position**
When you release the brake pedal, the recoil spring returns the piston very quickly. In the pressure chamber, there are fluid spaces, and the clearinghouse passes through the holes in the piston and the perimeter of the primary form, filling the spaces immediately.
The force of springs inserted through the piston flange, by moving from its seat in the valve from the liquid into the pressure chamber and the tank, stops the vehicle. When fluid pressure closes the valve seat to maintain residual pressure brake pipes, you obtain braking as quickly as possible.
**Types of Flaws in the Master Cylinder**
- Valve in poor condition
- Broken recoil spring
- Primary form in poor condition
- Piston hole plugged
- Poor secondary Goma
- Equalizing orifice clogged
- Filling hole covered
- Atmospheric pressure orifice clogged
**Drum Brake**
**Purpose**
To stop the rear wheels of the vehicle.
**Operation**
The liquid coming from the pump enters the cylinder and acts on the pump piston rod located, displacing the shoe against the drum and stopping the vehicle.
By stopping the pump, the force of the springs through the rods and pistons introduces a skate, returning the liquid to the pump and stopping the vehicle.
**Brake Shoe**
It consists of the metal part called the upper shoe, and the lining is attached to the flange by rivets or cured.
**Fixed Anchor Simple Command**
It has a single cylinder at the top of the bottom plate. The skates are fixed by means of an anchor pin. When the brake pedal is driven, it stops only 50% of the lining.
**Sliding Anchor Simple Command**
At the bottom, the flange has a series of guides which moves the skid when braking, increasing the surface by 60%.
**Double Command System**
At the top, it has the cylinder. When the vehicle slows, it reaches 100% of the surface of the lining, but the direction of rotation drags the lining, spending more than others.
**Brake Fluid**
Brake fluid is responsible for transmitting the force applied by the driver through the brake pedal to drain the vehicle’s wheels.
**Properties of Brake Fluid**
- Hydroscopic: Absorbs water that enters the liquid, condensing and alternating the boiling point.
- Ebullioscopic: Withstands high temperatures without boiling.
- Cryoscopic: Must withstand low temperatures without freezing.
- Lubricant: Must allow the movement of moving parts.
- Detergent: Must keep all the components inside the pump clean.
- Antioxidant and Anti-corrosive: Must protect all metal parts from rust and corrosion, a product of condensation water.
- Must protect all rubber parts.
**Brake Servo**
**Function**
The brake servo is responsible for increasing the force applied by the driver to the brake pedal to get the braking with the least effort from the driver.
**Operation: Braking Position**
When the pedal is not actuated, the valve closes the atmospheric pressure, and when the valve is depressed, the two chambers are communicated with repression or are empty.
**Braking Position**
When the brake pedal is activated, the pressure valve opens and closes atmospheric depression. Atmospheric pressure acts on the diaphragm area, displacing the piston rod of the pump, and the vehicle slows.
**Failures**
- Atmospheric valve in poor condition
- Pressure valve in poor condition
- Perforated rubber diaphragm
- Broken or expired spring
- Perforated flexible hose