Audi A4

since 1994 release

Repair and operation of the car



A4 Audi
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
+ System of injection
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
- Brakes
   Independent work on brake system
   So the brake system works
   Check of brakes
   Brake fluid
   Check of level of brake fluid
   Check of brake system on tightness and existence of damages
   Replacement of brake fluid
   Disk brakes
   Measurement of thickness of overlays of forward disk brakes
   Check of a condition of brake disks
   Replacement of overlays of disk brakes
   Back disk brakes
   Measurement of overlays of back disk brakes
   Emergency brake
   Check of idling of the lever of the emergency brake
   Main brake cylinder
   Brake amplifier
   Check of the brake amplifier
   Works on hydraulics of brake system
   Pumping of brake system
   The help at malfunctions
   ABS and EDS
   What does ABS?
   Function of separate knots
   Electronic system of distribution of brake effort (EBV)
   Violations in work of ABS system
   Electronic blocking of differential (EDS)
+ Wheels and tires
+ Electrotechnical equipment
+ System of ignition
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics





Replacement of overlays of disk brakes

Always it is necessary to change at the same time both slips at the left and on the right. Use slips only with AVA (General permission to operation). If the manufacturer of a brake is Lucas, when replacing slips are used two new samokontryashchikhsya a bolt. They most often are in a set of brake slips – check. If the manufacturer of a brake is ATE, bolts are not necessary.

As in process of wear of slips pistons all farther leave in brake supports, at installation of new, thick slips they need to be wrung out back. Thus brake fluid is wrung out via pipelines in a broad tank. If in this period brake fluid was in vain added, surplus needs to be sucked away now. Otherwise the brake fluid acting from a broad tank will corrode the nearby varnished details in a motive compartment. For suction use absolutely pure pipette or an old syringe for injections – never suck away liquid a mouth!

Replacement of a slip in ATE brakes

ATE brake: dismantle of slips, first stage: wring out a screw-driver (2) fixing spring (1).

ATE brake: dismantle of slips, second stage: weaken bolts with internal hexagons in protective covers (1 and 2) after removal of caps.

Third stage: the external slip (3) in the case of a brake support of ATE (2) is pasted, the internal slip (1) is inserted with metal brackets (shooter) into an internal opening of the brake piston.


The piston in a brake support is wrung out by a clamp. For protection we laid between them a small plate. The brake support of Lucas established here usually remains fixed above.


 PERFORMANCE ORDER

  1. Lift and record forward part of the car.
  2. Remove a wheel.
  3. Turn a wheel in order that slips were well available.
  4. Remove a screw-driver fixing springs from outer side on a brake support.
  5. Remove caps on inside of brakes.
  6. Establish a key with an internal hexagon in already visible internal hexagon of the directing fingers and weaken both fingers.
  7. Take out fingers, remove the case of a brake support.
  8. Suspend the case of a brake support on a wire on a depreciation rack.
  9. Take out slips on the right and at the left from the case of a brake support: an internal slip have to be taken out with fixing brackets from the brake piston, the external slip has to be unstuck from a brake support, – if it is necessary, with a force.
  10. Wring out pistons in a brake support by means of a clamp. In order that the piston did not warp or was not damaged, on an adjacent ring put a small plate.
  11. Carefully remove the remains of the gluing film on an adjacent surface of an external slip.
  12. Clean a brake support, the rust should not be, first of all, on directing.
  13. Insert new slips to paste an external support, remove a protective film from the gluing site.
  14. Establish a brake support.
  15. Tighten the directing fingers on 25 Nanometers and again put on caps.
  16. After assembly surely several times press a brake pedal so that slips lay down to brake disks. Otherwise there will be no brake effect!
  17. With new slips – if it is possible – brake carefully the first 500 km.

Replacement of slips in Lucas brakes

Lucas brake: unscrew only the lower fixing bolt (2) cases of a brake support. Wring out the directing finger to the opposite side. The top fastening (1) remains untouched.


Lucas brake: the case of a support (2) after weakening of the lower fastening leans back up. Slips (3 and 4) in the directing. Further it is visible: 1 – a heat-shielding guard in the brake piston.


 PERFORMANCE ORDER

  1. Lift and record forward part of the car.
  2. Remove a wheel.
  3. Turn a wheel in order that slips were well available.
  4. Unscrew only the lower fixing bolt of the case of a brake support, thus wring out the directing finger for a hexagon in an opposite direction.
  5. Cast away the case of a brake support up.
  6. Take out slips on the right and at the left from the directing.
  7. Wring out a clamp the piston in a brake support. In order that the piston did not warp or was not damaged, on an adjacent ring put a small plate.
  8. Track the correct position of the heat-shielding screen in the brake piston.
  9. Insert new slips.
  10. Mount a brake support.
  11. Tighten a new (!) lower fixing bolt on 30 Nanometers. Do not tighten the top fixing bolt, otherwise will disappear samokontryashchiysya effect. Use a narrow rozhkovy key for an extraction in an opposite direction of the directing finger, differently will jam it and the moment of an inhaling will be distorted.
  12. After assembly surely several times press a brake pedal so that slips lay down to brake disks. Otherwise there will be no brake effect!
  13. With new slips – if it is possible – brake carefully the first 500 km.

Dismantle of a forward brake support

Forward brake supports are attached to a depreciation rack by so-called ridge bolts. These bolts behind a six-sided head have a corrugated surface which is not allowing inadvertent weakening of a bolt. These bolts cannot be replaced with usual bolts by no means!

Here the support of a brake support is visible (3) at the dismantled case of a brake support. Figures "1" and "2" designated fixing bolts of a brake support (corrugated bolts).


 PERFORMANCE ORDER

  1. Unscrew a wheel.
  2. Dismantle brake slips with brake supports (as it is described in the previous sections).
  3. The case of a brake support with the screwed brake hose suspend so that the hose was not tense.
  4. Or unscrew a brake hose, or a tube. In this case wring out a pedal of a brake and hold it that brake fluid did not flow out.
  5. Unscrew fixing bolts of a brake support on a brake support.
  6. Before installation clean corrugated surfaces of ridge bolts.
  7. Tighten ridge bolts on 125 Nanometers.
  8. Again screw a brake hose or a brake tube.
  9. Pump over brake system in case the brake hose or a brake tube unscrewed.
  10. Before the first meters of the movement several times wring out a brake pedal to adjust a normal gap of a pedal.

Replacement of cuffs of the brake piston

If the cuff of the brake piston in a support is damaged, it is necessary to take care as soon as possible of replacement, differently soon the piston will jam because of dirt and corrosion. Cuffs are on sale only assembled with a pro-masonry ring of the brake piston. For installation of both details it is necessary to squeeze out the piston from a brake support. For the sake of safety this work needs to be carried out in a workshop. Depending on circumstances dismantle also brake support and carry it in repair.

Replacement of a forward brake disk

Brake disks need to be changed at once from both parties. Unilateral replacement can lead to unequal effect of braking.

 PERFORMANCE ORDER

  1. Completely dismantle a brake support as it is described, and fix a wire on a body. The hydraulic hose remains connected.
  2. The brake disk can be removed from a wheel nave only manually.
  3. If it prirzhavet, help yourself in strong blows of a hammer but only in case the disk changes.
  4. Before installation of a new brake disk clear an adjacent surface on a wheel nave.









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