Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ System of injection
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
- Brake system
   Check of brake mechanisms
   Brake fluid
   Check of level of brake fluid
   Check of tightness of brake system
   Replacement of brake fluid
   Disk brake mechanisms
   Measurement of thickness of blocks of the disk mechanism
   Control of a condition of brake disks
   Replacement of blocks of disk brake mechanisms
   Drum brake mechanism
   Measurement of brake shoes of the drum mechanism
   Check of the course of a pedal of a brake
   Disk brake mechanism of back wheels
   Measurement of thickness of blocks of back disk brakes
   Check of a free wheeling of the lever of the parking brake
   Main brake cylinder
   Amplifier of brakes
   Check of the amplifier of brakes
   Regulator of brake forces
   Repair of the hydraulic drive of brakes
   Pumping of brake system
   List of malfunctions
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

Measurement of thickness of blocks of back disk brakes

The hummock drive of system of the parking brake at the case of a support of the disk brake mechanism of models with disk brakes on back wheels


1 – tip of the hummock drive of the parking brake; 2 – driving lever of a support of the brake mechanism of the parking brake; 3 – returnable spring of the hummock drive of the parking brake;	4 – spring bracket; 5 – cover of the hummock drive of the parking brake.

Check of thickness of brake shoes:

6 – material of a frictional slip;
7 – carrier of a frictional slip.

On back disk brake mechanisms control of wear of blocks happens in the same way, as well as on lobbies. Limit wear and here makes 2 mm – without plate carrier thickness.

Along with control of wear of blocks an inspection of a condition of brake disks is carried out. Indicators of wear and sequence of performance of work same, as well as when checking forward disk brake mechanisms.

Replacement of brake shoes of back disk brakes

Except blocks, four are necessary samokontryashchikhsya a bolt which, as a rule, are included in the package with blocks. In spite of the fact that work of a legkovypolnim, nevertheless you can face problems if there is no special key 3131 of Audi workshop.

The following description, thus, can help only on condition that you can hire this key in a workshop or make it on a sample.

On an illustration a special key 3131 from a workshop of Audi push the brake piston of the back disk brake mechanism at the removed support of the brake mechanism back.

PERFORMANCE ORDER

To turn out both fixing bolts of the case of a support of the disk brake mechanism, holding thus the directing bolt for a hexagon.
Hand to pull the support case to outer side of the car.
Now to cast away it back and to remove.
To take out brake shoes from the directing.
To establish a special key 3131 to the brake piston and to screw the piston a strong hand pressure.
Ask the assistant to watch thus the level of brake fluid in a tank. If the tank is overflowed, it is necessary to pump out liquid.
Never push the brake piston without rotation with a great effort. In this case you will destroy the adjusting mechanism in the piston.
To establish new blocks.
To tighten the case of a support of the disk brake mechanism new samokontryashchimisya bolts the moment of 35 N • m.
To apply only a thin rozhkovy wrench to a priderzhivaniye of the directing bolt. Wide can jam, and in this case inhaling force will not coincide.
After dismantling of the brake mechanism it is necessary to make surely the main adjustment (see the following section).

Adjustment of disk brakes of back wheels

PERFORMANCE ORDER

To raise the car behind from both parties and to record. To remove wheels.
To remove from the parking brake.
To check that hummock drives of system of the parking brake were not under a preliminary inhaling.
For control to wring out the lever of inclusion of system of the parking brake on a support of the brake mechanism alternately to the right and to the left against the stop.
If the lever of a support of the brake mechanism of other wheel, also moves, so cables of the drive of the parking brake are tense too strongly. In this case to weaken the central adjusting nut of system of the parking brake until both levers do not reach precisely against the stop.
To put the car on wheels.
At the switched-off engine to press a brake pedal with an average force about 40 times.
Again to raise the car.
To check, whether wheels can freely rotate.

Removal of a support of back disk brakes

PERFORMANCE ORDER

To disconnect a brake hose in case it is necessary to replace a support of the brake mechanism.
To remove the case of a support of the brake mechanism as for replacement of blocks. Pay thus attention to the text above!
To remove hummock drives of system of the parking brake.
To turn out both fixing bolts of the support which is on an axis.
At installation to tighten fixing bolts of a support the moment of 65 N • m.
Carry out once again adjustment.

Replacement of cuffs of back brake cylinders

Replacement of defective cuffs of brake pistons on back supports of disk brake mechanisms happens as well as on lobbies.

Replacement of a back brake disk

PERFORMANCE ORDER

To remove a support of the disk brake mechanism.
To remove a brake disk.
To clear a prileganiye surface on a nave of a wheel or to smooth out a small skin and to put on a new brake disk.
To carry out adjustment according to the described scheme.

System of the parking brake

When actuating the lever of inclusion of system of the parking brake rigid draft under a car floor moves forward. On its end there is a yoke – the counterbalancing bracket. The cables of the brake drive going back to guards of brake drums or to supports of brake disks are attached to it. Purpose of the counterbalancing bracket consists in whenever possible evenly to distribute force which is applied at a tightening of the lever of the parking brake between back wheels. Fluctuations of coefficient of friction of both cables of a brake are counterbalanced by a yoke.

At models cables of the drive delay back drum brake mechanisms for levers of inclusion of system of the parking brake of back brake shoes and press them to a drum. At the same time the lever of inclusion of system of the parking brake leans through a press bar on a front brake shoe. Thereby it also brakes.
On models with back disk mechanisms cables of the brake drive affect via the driving lever, a press bar and the adjusting mechanism with the way described in the section "Disk Brake Mechanisms of Back Wheels".