Failure of vehicles braking system
Most vehicles involved in accidents nowadays are the big vehicles. Their braking system is quite different from the small cars. They have air tanks for their braking system. Small vehicles too are hard to brake unless the engine is running. But they don’t need a lot of air as the big ones. So the time the engine starts, enough air is made available to the brake system.
The parking brake (a.k.a. emergency brake) system controls the rear brakes through a series of steel cables that are connected to either a hand lever or a foot pedal. The idea is that the system is fully mechanical and completely bypasses the hydraulic system so that the vehicle can be brought to a stop even if there is a total brake failure.
On drum brakes, the cable pulls on a lever mounted in the rear brake and is directly connected to the brake shoes. This has the effect of bypassing the wheel cylinder and controlling the brakes directly.
For big vehicles like lorries, buses and trailers, the amount of air required is tremendous. That is why after starting a big vehicle; the engine is left to run or warm in order to pump enough air into the tank. This system is called an air system brake. It uses air as a way of transmitting pressure from the driver’s control to the service brake. It also has an air over hydraulic brake system.
This compressed air usually has some water and some compressor oil in it. It (water/oil) tends to collect at the bottom of the air tank. Each air tank is equipped with a drain valve at the bottom. If the tank is left for long without draining, this will be the starting point of the brake failure.
It is important to remember that water cannot be compressed. The more water in the tank the less the compressed air volume.
Whenever the foot brake is applied, a fairly large amount of the air is used. If the air pressure does not build up fast enough, the pressure may drop too low during driving, necessitating emergency stops. Brake failure then becomes a real danger regardless of the speed at which the vehicle is moving.
A number of things can cause brake failure: Defective parts like brake pads/shoes, the hydraulic lines, the air lines, etc. A vehicle that has something wrong with its brakes is an accident waiting to happen. Those that remember the IFA W50 may wonder what the problem really was with these military carriers. You could manually disengage the parking brake with no air in the tank. After push starting, drivers were never bothered to give the vehicles chance to fill the tank. That is where the problem started.
Squealing brakes is an indication of a problem with the brake system. Most of the time a squealing noise can be a warning to you that your brake pads are worn down and need to be replaced. Other causes can be overheated brake pads or rotors and sometimes rust can get impregnated on the brake lining material and cause grumbling or squeaking noises.
Antilock brakes’ (ABS) electronics failure results in loss of braking. When the ABS electronics fail, the brakes revert to conventional braking mode in most cases, with little or no loss of braking. Therefore, the vehicle inspector would look for signs of excessive wear, malfunctioning of the mechanical calipers that apply pressure to disc brakes, and do a complete check of the ABS system in the same manner as he would a conventional braking system. Upon finding no failure or defect to the ABS brakes, they would be ruled out as a cause of the crash.
A major problem to the brake system is a brake fluid leak, if there is a slow leak in the system it will effect the brake master cylinder by allowing air into the system creating a low peddle and eventual brake operation failure. If a large brake fluid leak is present, fluid escapes, leading to a major brake failure on one half of the system (front or rear). A master cylinder has a built in safety device, two separate hydraulic systems a primary and secondary, separating front and rear brake operation in case of front or rear brake operation failure, one system will still be present.
Rather than kill so many innocent lives, in case of a brake failure, bring the vehicle to a stop using the parking brake. The other alternative is changing to a lower gear, and turning off the engine. This should be done with caution as the steering wheel will also harden, but the amount of danger is less than the damage to other vehicles and nearby lives.
We need to take care of brake fade too. It is another type of brake failure caused by overheating of the brake pads. It is common on poor material brake pads.
If you have a bad brake booster then it automatically follows that you’ll have problems with your brake pedal as well. A low brake pedal is usually a telltale sign that your brake power boost unit has gone badly. Most of today’s brake boosters are vacuum controlled. To check your brake booster you may need a vacuum measurement gadget that will be connected to the brake booster.
Attached to the cylinder master are the brake lines. The steel brake tubing is transcended to all the wheel of your vehicle. Rusts are the worst enemies of the brake lines. To avoid these and leaks, regularly inspect the linings. Replacement is the best course of action in case of damages.
Running from the brake lines to the brake calipers as well as to the wheel cylinders are rubber brake hoses. It is advised to avoid their exposure to dirt, road grime, salt and other elements. These can make the rubber to become brittle and can produce crack. This will then lead to a failure in the brake system.
As well, it is worth noting that brake failure can be caused by water in the brake fluid. When the fluid gets hot, the water will vaporize. This steam can be compressed unlike the water. However, instead of the braking effort being transmitted to the wheels, it is dissipated and the car will fail to brake. So it is important not to forget changing the brake fluid at given interval.
Moreover conventional brakes produce longer stopping distances than anti-lock brake systems on wet surfaces, and this may be a legitimate consideration for the reconstructions.