BMW 3 series E30

Since 1983-1994 of release

Repair and car operation

14.38. Brake liquids

THE GENERAL DATA

That it is necessary to know to the consumer

Appointment of brake liquids – to transfer effort from the main brake cylinder to the wheel. A problem though also narrow, but extremely responsible: the brake system does not have right to refusal under no circumstances. This condition defines requirements to properties of brake liquids. They consist in the following.

Boiling temperature. Experience shows that the working temperature of a brake liquid in most flashpoints of system is approximately that: 60 ° With at movement on highway, 100 ° With in a city and 120 ° With in mountains. But it on the average, and in strained усиловиях it quite often reaches 150 ° With and even can begin to boil more as, for example, brake колодка at several emergency braking the liquid in an adverse situation heats up to 600 ° S.Poetomu, and it threatens with accident: the volume of the main cylinder is insignificant (only 5–15 ml) and as soon as the volume of vials of steam in system will exceed this size brakes completely will refuse. But also before, at the small sizes of steam stoppers, efficiency of brakes already considerably falls.

At modern brake liquids boiling temperature much more above critical (that is 150 °), but these cannot be under a delusion. The substances entering into their structure, generally very much гигроскопичны, that is easily absorb a moisture from air, and rubber cuffs serve as a bad barrier to this process. The boiling point of the "humidified" liquid in comparison with "dry" much more low, it easily falls to critical size and even further. Therefore in nameplate data always specify two values of temperature of boiling: without a moisture and with the maintenance of 3,5 % of water. If last is small, in system with disk brakes it is not necessary to apply such liquid.

Frost resistance. It is obvious that the liquid serving for transfer of pressure, should keep comprehensible fluidity even at a strong cold. It is accepted that its viscosity should not exceed 1800 mm2/with at-40 ° With for usual execution and 1500 mm2/with at-55 ° With for the special northern. At a choice of a product for use in the conditions of severe winter it is necessary to pay attention to it.

Compatibility with consolidations. The substances containing in brake liquids, inevitably cause swelling of sealing rubber cuffs, however this influence is limited by operating technical specifications.

Anticorrosive and greasing properties. For moving details of brake system the working liquid urged to serve as natural greasing as other antifrictional products in their zone of a friction are not present. All these requirements are satisfied with application of special additives and additives in commodity products.

The inquiry

"Neva" – the first-born of the modern number who nowadays fairly become outdated and has been removed from mass production (small-scale here and there has remained). The basic components – гликолевый an aether and a polyether with addition of an anticorrosive additive. The boiling temperature makes 195 ° With without a moisture and 138 ° With at the maintenance of 3,5 % of water. The frost resistance specification is sustained. "Neva" has colour from light yellow to the yellow. The main lack – the raised hygroscopicity owing to what in a year of operation the boiling temperature comes nearer to the critical. Only taking into account this circumstance also it is possible to use "Neva" which has no other restrictions to application on cars of any marks.

"Tom'" is developed on replacement of a liquid "Neva" for wide application. Colour – in limits from light yellow to yellow, as at "Neva". In structure "Tom'" – concentrated гликолевый an aether, a polyether, бораты, target additives. Temperature properties of a product are improved: boiling in "a dry" kind – 220 ° With, in "humidified" – 155 ° With, viscosity at-40 ° With no more 1500 mm2/with. Saturation by a moisture, near-critical, comes at this liquid approximately in two years of work. As a whole on экплуатационным to qualities "Tom'" on the standard international classification satisfies to modern specifications DOT-3 is mass, "ширпотребный" a class without any special restrictions on application.

"Dew" – a product concerning the most perfect type. The basic component – борсодержащий a polyether along with special purpose additives. Colour – from light yellow to light brown. Boiling indicators are that: in "a dry" kind – 260 ° With, in "humidified" – 165 ° With, thus the critical indicator (150 °) is reached only after three years of a finding of a liquid in a hydrodrive of brake system. According to the international classification "Dew" satisfies to all norms of class DOT-4 that for today is the highest level of operational qualities. "Dew" without restrictions suitable for use in modern domestic and foreign cars.

Foreign products. Today in our market it is possible to meet set of import brake liquids (Brake Fluid). If such liquid is recommended by the manufacturer for any cars and thus has marks DOT-3 or DOT-4 it can be used equally both in foreign cars, and in domestic cars. As to operational qualities at comparison in a corresponding class (DOT-3 or DOT-4) import liquids are approximately identical to our "Tom'" or "Dew" and have no any special differences from them.