Audi A4

Since 1994 of release

Repair and car operation



Audi А4
- Running gear
   Protection of passengers
   Full zinc covering
   Full drive
   Drive concepts on all wheels
   Distributive torsen-differential
   Dynamics of movement on dry road
   Maintenance instructions of cars quattro
   The mechanism of blocking of differential
   Additional works on maintenance service
   Impellent compartment
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ Exhaust system
+ Cooling system
+ Fuel tank and the fuel pump
+ The air filter and channels всасывания
+ Injection system
+ Coupling
+ Transmission and the main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tyres
+ The electrotechnical equipment
+ Ignition system
+ Illumination
+ The alarm equipment
+ Tools and devices
+ Heating and ventilation
+ Body details
+ Salon
Search of malfunctions
Technical characteristics



Running gear

On the design four levers of an independent suspension bracket correspond to forward axis Audi A8. At the expense of an arrangement of four cross-section levers that in management drive influence practically is not felt is reached.


In three drawings it is shown, where is – imagined – the left axis (arrow) at various turns of a wheel. Position of an axis with operated wheels is especially important at neutral position of wheels. In this case it is almost precisely in the wheel centre.


Audi A4 with a forward drive has the so-called back bridge with the interfaced levers. Basically it consists of two pipelike longitudinal levers which are connected by a krutilno-plastic V-shaped profile.


At Audi A4 quattro the so-called bridge with double cross-section levers in which centre there is a drive on back wheels is behind established.

The forward bridge

At four levers of an independent suspension bracket of a forward axis in Audi each wheel copes four aluminium cross-section levers. Two top cross-section levers are fixed on a design by means of резинометаллических bearings and connected to a wheel support spherical heads with the lowered friction. Both bottom cross-section levers of a suspension bracket (on one – bearing and leading levers) are fixed on a stretcher by means of резинометаллического the bearing, and each of them is connected to a support of a wheel a spherical head with the lowered friction. The gazonapolnennyj shock-absorber and a screw spring are connected in an amortisation rack. The amortisation rack does not incur a problem of management of wheels. The additional spring from cellular полиуретана in a combination to a coupling buffer spring in shock-absorbers provides comfortable interception of strong fluctuations of a body on a forward axis.

Levers of an independent suspension bracket are located in such a manner that substantially smooth out приподниманием a forward part of the car in a start of motion and its lowering during braking. For decrease in longitudinal movements of an axis the internal bearing of the leading lever демпфируется a hydraulic way. The tubular stabilizer fixed on a stretcher which is connected to the bearing lever by means of a rod, reduces a body list on turns.

At the expense of aluminium use in various details of an axis and in a constructive configuration, and also as a result of application of high-strength materials in springs it was possible to keep low weight of an expensive design of a suspension bracket. Positive properties of a forward suspension bracket with four levers of an independent suspension bracket form the block with operated wheels which passes almost vertically through the wheel centre. With operated wheels the engineer means a prospective line round which the wheel moves at wheel movement by the block. The block with operated wheels near to the wheel middle possesses the big advantages as at a forward drive along with the efforts put for turn of a wheel, are transferred also приводные efforts which are applied again in the wheel centre. The distance between an axis with operated wheels and the wheel centre less, the more shortly the lever and the is less influence of hindrances on a steering.

At a forward axis with four levers of an independent suspension bracket in А4 influence drivers efforts to a steering as the distance between an axis with operated wheels and the centre of a wheel is not enough is almost eliminated – it makes only 10 mm.

The back bridge in cars with a forward drive

The known back bridge with the interfaced levers consists of two rigid on a bend and the krutilno-rigid pipelike longitudinal levers connected krutilno-plastic, rigid on a bend by a V-shaped cross-section profile. The additional stabilizer is welded with the ends of longitudinal levers. Thanks to it high cross-section rigidity of the bridge and outstanding stability of a track are reached. This back bridge should be anew adjusted concerning many details. Thus the priority purpose is increase of comfortableness and stability of movement, decrease in noise and weight reduction.

The design of the back bridge with the interfaced levers promotes that at simultaneous compression of both wheels he behaves as the back bridge with longitudinal levers, and at serial compression of a spring amortisation telescopic rack as the diagonal lever of an independent suspension bracket of the back bridge.

The back bridge of models Quattro

Models Audi A4 quattro are supplied by dual cross-section levers of an independent suspension bracket of wheels, including elastic support for back wheels. The top cross-section levers located over wheels, provide possibility of the device of the big luggage carrier.

The directing system of a suspension bracket of a wheel is provided with two triangular cross-section levers with additional стрежневым the lever from each party. Shock-absorbers and screw springs are united for economy of a place in amortisation racks.

Brake system with ABS

The serial system of antiblocking of the fifth generation with electronic distribution of brake effort EBV provides high stability of braking in the most different traffic conditions and does unnecessary a mechanical regulator of brake effort. As electronic control ABS possesses much more sensitive reaction, than a mechanical regulator of brake effort it is used essentially больший an adjustment range. To provide stability of movement also at braking on turns, the share of brake effort on a back axis should be lowered. EBV distinguishes by means of gauges of frequency of rotation ABS, whether moves Audi A4 rectilinearly or passes turn. On turn brake pressure upon back wheels decreases. Thanks to it back wheels can give the maximum effort of lateral withdrawal.

The electronic mechanism of blocking of differential EDS

EDS it is serially established on all models А4 quattro and enters in спецкомплектацию frontdrivers models with four-cylinder engines with working volume from 1,8 l.

At electronic blocking of differential EDS in all-wheel drive models it is a question of purposeful frictional coupling to three wheels, in front-wheel cars – one wheel. At the expense of it at трогании from a place in extreme conditions, for example at slippery road, the maximum draught is provided.

Electronic adjustment of proslipping of wheels ASR

In front-wheel models А4 with engines V6 with working volume 2,6 and 2,8 l in quality спецкомплектации for draught improvement are offered electronic adjustment of proslipping of wheels ASR which possesses also all functions EDS. If EDS includes purposeful frictional coupling for draught improvement electronic adjustment of proslipping of wheels ASR if necessary provides additional intervention in engine management. The sense of electronic adjustment of proslipping of wheels consists in avoiding пробуксовывания forward wheels irrespective of, how many gas the driver gives.