BMW 5 Series E39

since 1996-2001 release

Repair and operation of the car

Anti-blocking system of brakes (ABS)

The ABS system increases active safety of the car, preventing blocking of wheels when braking. Blocking of wheels is exclusively dangerous as forward wheels become uncontrollable, and the skidding back wheels can lead to a drift of the car and emission on other party of the movement.

The ABS system allows in any specific conditions (at the movement on a straight line, on turn, on the asphalted, ice-covered or wet road, etc.) to reduce a brake way to a minimum.

In principle at each braking of ABS has to solve two problems, providing:
- trajectory stability on the roads different in covering type (asphalted, concrete) and being in a different state (ice-covered, covered with dirt, snow or on wet roads)
- reliable controllability and maneuverability of the car under the called conditions

These requirements need essential comments.

ABS does not cancel operation of laws of physics. The system cannot prevent a consequence of the braking executed at an insufficient distance to ahead the going car, passing of turns with unacceptably high speed or with danger of hydroplaning. These consequences still remain on conscience of the driver. Existence of ABS providing the increased safety potential should not provoke you to excessively risky driving.

Features of driving with ABS

After launch of the engine the alarm lamp of ABS on an instrument guard dies away.

The system automatically joins only on reaching speed about 8 km/h. At its falling lower than 3 km/h of ABS are disconnected so theoretically at the latest stage of braking of a wheel can be blocked, however in practice it has no basic value any more.

ABS realizes process of regulation for fractions of a second. The pedal pulsation under a leg means that braking happens under ABS control, otherwise, that the driver goes in the boundary mode. Besides, the crackling caused by ABS work process reminds the driver of need of reduction of speed in compliance with the actual traffic conditions which changed because of reduction (for example, in connection with ice) friction coefficient (or couplings) between tires and the road.

On roads with a loose coating (for example, crushed stone or snow) over the basis with good coupling properties the brake way can be longer, than when blocking wheels. Told treats also the movement with antisliding chains. Much more important, however, a prize in trajectory stability and controllability of the car.

To keep operability of ABS in full, you do not make change to it. Works on system have to be performed only by forces of the experts authorized on that.

The movement on diverse tires, for example, after installation of a spare wheel (in combination with three other wheels on which tires with the winter drawing of a protector are mounted) can limit functionality of ABS. Therefore the removed wheel needs to be established as soon as possible back.

Signal of malfunction is inclusion of an alarm lamp of ABS on an instrument guard (address the Section Governing bodies and devices). In this case the brake system continues to work as a usual order, as well as at cars without ABS. However as soon as possible address on CTOA BMW for check of the brake system. Otherwise in it there can be malfunctions which are difficult giving in to detection.

Hydraulic booster of steering

At the heavy course of steering it is necessary to check oil level according to recommendations in the Head Proverka of levels of liquids.

If difficulties arise in attempt of bystry turn of a steering wheel, then for check it is necessary to address surely on CTOA BMW.

At failure of the hydraulic booster the effort necessary for turn of a steering wheel increases.