| ABS or Antilock Braking Systems were originally designed and developed
for aircraft, allowing the pilot to stop them safely in all conditions. ABS
is designed to stop the wheels from locking up and skidding when braking
hard or on wet or slippery surfaces. This is a significant safety feature
that has prevented thousands of accidents since it was first introduced onto
cars in the early 1990’s.
ABS doesn't always reduce your stopping distance. In fact your stopping
distance can actually increase on dry roads. The real advantage is where the
road is wet, ABS can reduce the stopping distance by more than 25%.
Remember the only contact that your car has with the road surface are
it’s tyres. When you brake hard there are tremendous forces of friction from
the road surface and the rubber compound of the tyre's. It's these friction
forces that stop the car.
A tyre produces it’s maximum braking effort just before it skids. Once the
wheel locks the friction is decreased and the stopping distance increases.
The only exception to this rule is when a car is on loose snow. A locked
tyre on loose snow allows a wedge of snow to build up just in front of it
which helps it to stop in a shorter distance than a rolling tyre. It is for
this reason that some ABS system manufacturers include a snow switch that
turns the system off normally at speeds below 10mph.
Also remember that when your front wheels are locked turning the steering
wheel will have no effect at all. ABS allows you to brake really hard and
take avoiding action. ABS only comes into play when traction is reduced or
during emergency stops. Most of the time, it has no effect on your normal
driving or braking.
ABS systems are pretty bomb proof however if a problem occurs, most systems
will deactivate themselves and switch on the ABS warning light.. The vehicle
should still have normal braking control. The vehicle will be safe to drive,
but without ABS. Bear in mind however that a vehicle will fail it’s Mot if
the ABS light is on, and there may be problems with standard braking system.
So get it checked.
How ABS Works
The wheels are fitted with speed sensors. These sensors constantly monitor
each wheel and send signals to a control unit. When a wheel starts to lock
the control unit overrides your braking and decreases the pressure to the
locking wheel. So if one wheel starts to slow down quicker than the others,
or at a faster rate than is programmed the control module takes over.
Electrical solenoid valves and an ABS pump are used to release and reapply
the pressure to the brakes. This produces a rhythmic ‘pulsating' effect,
which is felt through the brake pedal. On some cars, the pedal sinks towards
the floor and very little pressure is felt by the driver as the system takes
over completely. The driver may also hear a ‘banging' noise from the ABS
hydraulic unit.

This rapid applying and releasing of brake pressure in the brake circuit
reduces the load on the wheel and allows it to maintain traction, this is
the same as pumping the brakes very quickly with your foot (cadence
braking), except that the ABS system does automatically, and at speeds that
would be completely impossible for a driver to imitate. Many systems can
‘pump the brakes’ 40 times per second.

The pressure in the braking system is released by high speed valves.
After the pressure has been released, the control unit needs to reapply it.
It does so by means of an ABS pump (pictured above). It then opens the valve
to release the pressure, then activates the pump to reapply it, and the
whole cycle goes on and on at unbelievably fast rates.
Once the braking for all the wheels returns to normal and the danger of a
lockup is avoided, the car reverts to normal braking and antilock reverts to
a passive mode.
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ABS is now also fitted as standard to some motorcycles, On bikes, there's
usually a sensor and an ABS control module fitted to both wheels. If there's
only one it's always fitted to the front wheel.
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By the time you
realise that you have a brake problem it is probably too late!
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Brake fluid is
hygroscopic, and should be replaced regularly. When was yours last
changed?
*
On a first date give
your immune system a boost by eating raw garlic
*
Brake fluid will
damage paintwork, so try not to spill it.
*
Old engine oil is
carcinogenic so drinking it is not advisable
*
Car batteries
contain dilute Sulphuric Acid
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Get the most out of
life- Become very rich.
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