Audi 100/A6

1990-1997 of release

Repair and car operation

Audi 100/A6
+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engines
+ 3.2. Diesel engines
+ 3.3. Removal and partition of engines
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Systems of start, ignition
+ 9. Transmission
+ 10. Brake system
+ 11. Suspension brackets, steering
+ 12. Body
+ 13. Electric equipment
- 14. Good advice
   14.1.1. Changed numbers
   14.1.2. Purchase of the old car or mysterious set of figures and letters
   14.2. Durability of the car
   14.3. About parallelism of bridges of the car and the trailer
   14.4. Preparation of the car for winter
   14.5. It is not got – good advice
   14.6. From change of places "composed" changes nothing?
   14.7. Visit to car-care center
   + 14.8. Engine
   + 14.9. Conditioner
   14.10. Turbokompressor
   + 14.11. Rub in one – or how to save the catalyst
   + 14.12. Accumulator
   14.13. Generator
   14.14. Probuksovochka
   14.15. "Machine gun"
   - 14.16. Brake system
      14.16.2. ABS: natural choice
   + 14.17. Wheels and tires


14.16.2. ABS: natural choice


To formulate purpose of ABS it is simple – it interferes with blocking of wheels when braking. The brake pedal is too strongly pressed? It doesn't matter – electronics, comparing signals of sensors of speed of rotation on each of wheels, defines the moment of a sudden stop of a wheel and, opening the electromagnetic valve, dumps surpluses of pressure from the brake highway in the special hydroaccumulator. Brake shoes are unclenched, rotation of a wheel is restored, the valve connects again the highway to pressure which by means of the vacuum amplifier of brakes is created by the right foot of the driver. And if this pressure is still too great, the cycle repeats again and again. In salon inclusion of ABS is shown by a crash at operation of the executive block and pushes on the brake pedal, more or less appreciable depending on a system design. Actually, ABS simulates actions of the skilled driver which on the slippery road avoids blocking of wheels, using faltering braking. But ABS does it with frequency inaccessible to the person and accuracy – to 15 times a second.

As a result of ABS should not only provide to the car the minimum brake way, but also force it to answer the helm – after all wheels slide and perceive lateral force coupling of tires with a covering how allows. Also it is the main advantage of ABS. After all in case of blocking of wheels the car it is uncontrollable slides directly, even when the steering-wheel is turned out against the stop.


It would seem, everything is already clear. Anti-blocking systems are recognized as all civilized auto world and already became the standard equipment on cars, since middle class. But voices of the dissatisfied are often distributed also.

"No electronics will be compared to the skilled driver, – tell one. – Give me the same car without ABS, and I will stop earlier!"

Another do not like that ABS, interfering with braking process, absolutely excludes participation of the person. As press on a pedal, it with not palatable vibration will be back pushed out. The car brakes itself, to affect a course of delay it is impossible in any way, besides with ABS it is very difficult to calculate a brake way and to predict, where the car will stop. It is necessary to wait only... Intolerably for the driver, got used to own a situation!

And the third nod on rally drivers. A pier, not without reason those are afraid of ABS, as plague! And to them, athletes, more visibly...

The sensor of speed of rotation of a wheel settles down in a nave


To place everything in places, we went on a technological crime. Found under a cowl the tip which approaches to the ABS executive block, and pulled out it from a nest, having forced to light up yellow контрольку ABS and is disturbing to start blinking a red bulb of brakes in a combination of devices. So we deactivated not disconnected anti-blocking system. Tests passed according to such scheme. We chose four main exercises: braking on a straight line – on the homogeneous and mixed covering (миксте), in turn and during an obstacle detour (that is at maneuver performance a rerate). Passat equipped with the data-acquisition equipment which is precisely measuring speed and a brake way. And at a wheel there were our experts verifiers. However, some of exercises were offered for making and to ordinary drivers of the most different qualification – from the beginning motorist to the skilled professional. All could be trained before control arrivals, get used to the car and "adjust fire" to the next maneuver.

Each exercise carried out in two series. At first did more than ten arrivals from working ABS, then disconnected system, and the car hurried again to the route of the next maneuver marked by bright landmarks.


With anti-blocking system everything is simple: you want to receive the greatest possible delay – a bog, without thinking twice, a pedal in a floor. And how to brake without ABS?

At first we tried everything to do "according to the theory" – to brake on the verge of blocking of wheels. Does not leave! Too sensitive folksvagenovsky pedal does not allow to dose out precisely brake force – and we are mistaken, and both in that, and in other party. And it in a quiet situation. And try it to make in an extreme situation when failure threatens!

Then we applied the tested way – faltering braking.

And for comparison tried, without philosophizing crafty, to brake "in a floor", with blocking of wheels. In what a difference? On a straight line the main difference – in course stability. Especially brightly it was shown when braking on миксте. Under the left wheels there was a wet asphalt, and under right – a snow-covered roadside.

Braking with blocking of wheels

1. Faltering braking

2. Braking with ABS

3. Braking beginning, speed of 64 km/h

From included ABS the car at first starts to withdraw towards a covering with the best coupling, but electronics works regularly: Passat is instantly leveled and further brakes on a straight line, practically without demanding podrulivaniye. During faltering braking without ABS the driver had to taxi up a little and the brake way appeared more.

But with complete blocking of wheels the car braked almost as is effective, as with ABS. But thus it sharply developed to the left on a dangerous corner – to 40 °! ABS prize here is obvious.


Ice happens smooth, as a mirror, and rough, as a sandpaper surface. Snow happens dense, unrolled, friable, bound together, frozen together...

To what it we? And to that each covering has the specifics, and after our tests to give a definite answer on a question interesting all – in what conditions the brake way with ABS will be less, than without it – we cannot!

Options weight. For example, when at numerous stops on the same straight line of a wheel of our car накатали a track of the rough ice crumbed by thorns, the brake way with ABS and without it with the blocked wheels appeared almost identical. Not without reason our athletes say that the most "tenacious" covering – not asphalt, and ispolosovanny "nails" an ice track. And on snow – here so a surprise! – the car with ABS stopped a little later. All the matter is that on a snow covering the factor of coupling appeared lower, than – thorns here work at rough ice not so effectively. For ABS, probably, it appeared unprofitable. But at "usual" faltering braking (pressed – released – pressed) during blocking of wheels before them the snow roller which helps the car to be slowed down more intensively is formed. Work of ABS interferes with wheel blocking – and the roller it is impossible.



Imagine quite real situation: before you in slippery turn suddenly brings the truck, and it develops across the road. Or another: from lateral journey on rather narrow street directly before a nose the car jumps out and partitions off your strip, leaving free only counter.

On a wave of the adrenaline which has rushed in blood the driver in panic, reflex, with all the might will press a brake. Wheels will be blocked. And with the blocked wheels the car in the first situation will take off outside of turn, and for the second – врежется in an obstacle. For without ABS to avoid failure only faltering braking will help, and here from the driver it is required not only outstanding composure and endurance, but also uncommon skill.

And here our example. The most experienced expert needed to call to the aid all the ability that, alternating strictly dosed out pushes on pedals of a brake and exact work as a wheel, to repeat and even slightly to surpass results of the same maneuvers with ABS.

But what from that? After all even the verifier needed to make for this purpose more than ten ranging arrivals, and in a real situation the chance will be only one! And electronics here will work reliably and in the benefit.

When braking in turn the task of the driver in general was the elementary: pressed a brake, turned a wheel – and the car, accurately tracing the set trajectory, it is intensively slowed down. It is available to any. It is important to remember only that during braking with ABS by car it is possible and it is necessary to operate. Did not freeze to compress a wheel, and dared to operate with it!

At an obstacle detour (we braked at performance of maneuver of a rerate familiar to our readers) the situation was such. When speed of performance of maneuver came nearer to limiting, after a detour of an obstacle drift of a back axis started to develop. It was both with ABS, and without it. But using ABS, it was possible to reduce speed so that drift was not so sharp and deep. And the brake way after a detour on 15 meters was shorter. Essentially!

However, to keep on the road, at correction of drift it was necessary to release a brake pedal even at working anti-blocking system. Why? We do not argue, ABS leaves possibility to change a trajectory at emergency braking, instead of to slide on a straight line with the blocked wheels. But at fight against drift ABS work too reduces efficiency of correcting actions by a wheel. And even to those drivers, whose cars are equipped with ABS, in similar situations it is necessary to be ready for an instant to release a brake pedal, having meaningly refused electronics services.


ABS is worthy the anthem! Also the head from bewilderment is turned: how probably such? In cold winter evening and on the slippery road and on decent speed it is possible to throw simply a wheel and it is stupid to stamp a foot on brakes – and not крутанет the car, will not throw aside, a swallow... It only it is impossible to touch defect with impunity, and to a brake pedal by the car from ABS – it is possible! But it is careful...

The delight and horror, horror and delight are tested by the "green" driver. Delight clearly from what – from feeling of permissiveness. And horror - from a deep-rooted presentiment "and suddenly?" Suddenly will not work ABS? The rope on a swing breaks! Wires of sensors of ABS system on wheels – by the way, the main reason for its breakage break also.

Well, brakes continue to work, but unless as before? And there is a question how this ABS – anti-blocking system of brakes works?

In brief so: the ABS electronic block by means of sensors watches speed of rotation of wheels in a braking mode. And operates effort of braking on each wheel so that the car kept straightforwardness of the movement to a full stop. That is you press to yourselves on a brake pedal, and the clever car to impropriety itself redistributes efforts of braking between wheels for their simultaneous stop. The brake pedal by the car from ABS unusually shakes, as though leads the life (not to confuse to curve brake disks, absolutely other podragivaniye).

And if does not shake? Means, the ABS system "died", having nobly lit before death on the dashboard a display lamp of "ABS" usually red, occasionally yellow color.

In a normal mode at ignition inclusion the inscription of "ABS" should go out through нескольку seconds after regular self-diagnostics of the ABS block (at some cars a display bulb of "ABS" dies away if slightly to pass).

So: burns, "ABS" does not die away! That will show the specialized computer at connection of your concrete car, we do not know. Volumes of books about that are written moreover and on years the different. Cases rather unusual, i.e. "tasty" are remembered.

Action 1. "ABS" inscription that burns, does not burn. Options of unpleasant behavior of the ABS indicator a little, and interesting – such. The semi-axis fastens in the bridge a cutting washer and more anything. The semi-axis wore out, the washer "was eaten" – both that, and another purely Russian diseases – and now the semi-axis is capable to leave from under the car together with a wheel. The ABS system sensor strong costs on a bridge stocking, and the faulty semi-axis goes by it there-here.

The owner of the car, clear business, feels nothing, but blinking of a bulb of "ABS" disturbs him. The semi-axis rotates on a place, the sensor reads out from it a signal, ABS works. The car turned, jumped up and so forth – the semi-axis leaves a bridge stocking, the signal of the ABS sensor vanishes, the ABS system finds malfunction and lights an emergency lamp of "ABS".

And all делов was to pull at a wheel.

Action 2. The complaint arrived: "ABS" bulb is lit. Modestly we ask:

– And with car something did?

– Well, here headlights put, and all.

It already "zatsepochka". Not at once it becomes clear that about Niagara Falls "expert" connected headlights in capacity directly to the ABS block. At their inclusion not only that planes go off-course, but also vanishes or the supply voltage on the electronic block of ABS system "sits down". Here he also does not want to work, cannot. But there is a lot of light.

Action 3. Unusual, from a series "never trust the client". The circle "ABS" is lit, then goes out – everything as it is necessary. But it is necessary to pass two-three meters – it is lit. That is, the ABS system reports that a pier – it is bad it.

There is no urine, there are no forces correctly to "fulfill" ABS! Well all checked – there are no breakages. And suddenly, absolutely casually we look out for a gear on a semi-axis from which the ABS sensor reads out speed of rotation of a wheel. On one semi-axis it differs from the others – because not that year of release, and on it it is less than teeths. The system of tracking speed of rotation of wheels also "goes mad", as on her electronic concepts the wheel turns "incorrectly". And the client, as always, holds the ground: assures that with car anybody never did nothing it!