Steering system (Audi 80 B4)

AUDI 80 cars are equipped with hydraulic power steering (servo control). The driver's efforts to control the vehicle are supported by hydraulic fluid, which is pumped under high pressure into the steering gear housing and additionally acts on the steering gear rack. The direction of the fluid pressure depends on the position of the steering wheel. The rotation of the steering wheel is transmitted to the valve, which determines the direction of supply and the amount of hydraulic fluid supplied to the system. The pressure in the amplifier is created by a pump driven by the crankshaft via a V-belt or V-belt.

If the fluid level in the hydraulic booster expansion tank drops, the system must be checked immediately. Otherwise, sudden failure of the servo control cannot be ruled out.

1. Turn the steering wheel from lock to lock in one direction and then the other. This will increase the pressure in the system and make it easier to identify the leak.

2. Leave the steering wheel turned all the way to one side and inspect the following parts, which are most likely to become depressurized.

3. Check the valve with a rotary valve located at the junction of the steering column and the steering gear. If there is a leak at this point, hydraulic fluid will leak into the passenger compartment along the front wall under the instrument panel.

4. Inspect the toothed rack seal. To do this, loosen the clamp securing the protective cuff (cover) and move the cuff to the side.



5. Inspect the power steering pump. To do this, the pump should be washed (see illustration).



6. Check all connecting joints and tighten nuts or clamps if necessary.

Steering - play adjustment

The steering play that has developed during vehicle operation can be eliminated provided that the wear of the toothed rack is insignificant.

7. Adjust the steering wheel so that the wheels are straight.

8. Ask an assistant to turn the steering wheel. You should hear clicking sounds.

9. Turn the steering gear adjusting screw to the right until these sounds disappear. Screw in the adjusting screw carefully and slowly (see arrow in illustration).



10. Perform a test drive. The steering gear should not be difficult to operate in any position of the steering wheel. If not, replace the steering gear.

Power Steering - Checking Fluid Level

11. Start the engine and let it idle.

12. Align the wheels.

The fluid level in the transparent expansion tank should be between both marks on the tank. These marks on the tank are not available on all AUDI models. In such cases, use the liquid level indicator rod (dipstick).

13. Remove the reservoir cap to which the dipstick is attached. Be careful, the cap is equipped with a spring.

14. Wipe the dipstick shaft with a clean cloth and insert the dipstick into place until the cap fits. Do not screw the cap on.

15. Remove the dipstick again and check the fluid level in the reservoir. It should be between both marks on the dipstick (see illustration 13.13).

A drop in the fluid level indicates a fluid leak from the system. Therefore, before adding fluid to the reservoir, inspect the power steering, identify and eliminate the leak

Power Steering - Filling Fluid and Bleeding Air

It is necessary to fill the hydraulic booster with fluid and bleed it when replacing its parts, which requires draining the fluid.

16. Wash the power steering expansion tank filter with cleaning gasoline.

17. Fill the reservoir with new hydraulic fluid up to the MAX mark. Do not reuse the old hydraulic fluid.

18. Place the car on jack stands and, without starting the engine, turn the steering wheel sharply from lock to lock several times.

19. Add hydraulic fluid to the reservoir up to the MAX mark.

20. Start the engine and observe the fluid level in the expansion tank. If the level has dropped, align the wheels and add fluid to the tank until the level stops dropping. In addition, when turning the steering wheel, no air bubbles should form in the tank.



21. Check the fluid level in the reservoir by performing a short test drive.

[The original version of the article is posted on the website audimanual.ru]