BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engine
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
- 14. Useful tips
   14.2. The changed numbers
   14.3. Purchase of the old car or mysterious set of figures and letters
   14.4. Durability of the car
   14.5. About parallelism of bridges of the car and trailer
   14.6. Preparation of the car for winter
   14.7. Rule 35
   14.8. Choice of the used car
   14.9. Engine oils
   14:10. What needs to be known, changing oil
   14:11. Emergence in deposit oil
   14:12. Whether it is possible to mix import oils?
   14:13. "Eats" much, but quietly goes
   14:14. It is rather live, than is dead …
   14:15. It is not got - useful tips
   14:16. Visit to car service
   14:17. A gear belt for the gas distribution mechanism drive
   14:18. Wear of pistons
   14:19. Valves
   14:20. Bearings of engines
   14:21. Pollution of the engine
   14:22. As the conditioner works and what to do if it failed
   14:23. Conditioner: not only "pluses", but also "minuses"
   14:24. Rules of service of the conditioner
   14:25. Antifreeze you should not disturb with antifreeze …
   14:26. What should be known upon purchase of the air filter
   14:27. Engine overheat
   14:28. What should be known to the owner of the car with the injector engine
   14:29. Accumulator
   14:30. Possible malfunctions of the rechargeable battery
   14:31. What to do with the failed generator
   14:32. The belt is guilty, and we blame the generator
   14:33. Catalyst
   14:34. Rub in one - or how to save the catalyst
   14:35. Probuksovochka
   14:36. Features of operation of the brake system
   14:37. Malfunctions of the brake system
   14:38. Brake fluids
   14:39. ABS: natural choice
   14:40. Rims
   14:41. We update rims
   14:42. Scheme of marking of a car tire
   14:43. Metal corrosion
   14:44. Automake-up
   14:45. What creaks?
   14:46. Hatch
   14:47. Safety cushion: troubles or pleasures?
   14:48. We fit well?
   14:49. Anticreeping "immunodeficiency"
   14:50. Why headlights grow dull
   14:51. Galogenka
   14:52. About the correct adjustment of headlights
   14:53. Electric motor
   14:54. From change of the places "composed" nothing changes?


14:38. Brake fluids


What the consumer needs to know

Purpose of brake fluids – to tell effort from the main brake cylinder to wheel. Task though narrow, but extremely responsible: the brake system has no right for refusal under no circumstances. Requirements to properties of brake fluids are defined by this condition. They are as follows.

Boiling temperature. Experience shows that the working temperature of brake fluid in the most hot spots of system of approximately is as follows: 60 °C at movement along the highway, 100 °C in the city and 120 °C in mountains. But it on average, and in intense usiloviya it quite often reaches 150 °C and even more as, for example, the brake shoe at several emergency braking heats up to 600 °C. Therefore liquid in an adverse situation can begin to boil, and it threatens with accident: the volume of the main cylinder is small (only 5-15 ml) and as soon as the volume of vials of steam in system exceeds this size, brakes completely will refuse. But also before, at the small sizes of steam traffic jams, efficiency of brakes already considerably falls.

At modern brake fluids temperature of boiling is much higher critical (that is 150 °C), but these cannot be under a delusion. The substances which are their part mostly are very hygroscopic, that is easily absorb moisture from air, and rubber cuffs serve as a bad barrier to this process. The boiling point of the "moistened" liquid in comparison with Sukhoi is much lower, it easily falls up to the critical size and even further. Therefore always specify two values of temperature of boiling in passport data: without moisture and with the maintenance of 3,5% of water. If the last is small, then in system with disk brakes such liquid should not be applied.

Frost resistance. It is obvious that the liquid serving for transfer of pressure has to keep the acceptable fluidity even at strong cold. It is accepted that its viscosity should not exceed 1800 mm2 / with at -40 °C for usual execution and 1500 mm2 / with at -55 °C for special northern. At the 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 which are contained in brake fluids inevitably cause swelling of sealing rubber cuffs, however this influence is limited by the existing technical standards.

The anticorrosive and greasing properties. For moving details of the brake system working liquid is designed to serve as natural lubricant as there are no other antifrictional products in their zone of friction. All these requirements are met by use of special additives and additives in commodity products.


Neva – the firstborn of a modern row, nowadays fairly outdated and removed from mass production (small-scale remained here and there). The main components – the glycoleft air and polyair with addition of anticorrosive additive. Temperature of boiling makes 195 °C without moisture and 138 °C at the content of 3,5% of water. The standard of frost resistance is sustained. Neva has color from light yellow to yellow. The main shortcoming – the increased hygroscopicity owing to what in a year of operation temperature of boiling approaches critical. Only taking into account this circumstance it is also possible to use Neva which has no other restrictions to application on cars of any brands.

Tom is developed on replacement of Neva liquid for broad application. Color – ranging from light yellow to yellow, as at Neva. As a part of Tom – the concentrated glycoleft air, polyair, borata, target additives. Temperature properties of a product are improved: boiling in a "dry" look – 220 °C, in "humidified" – 155 °C, viscosity at -40 °C no more than 1500 mm2/page. Saturation by moisture, near-critical, occurs at this liquid approximately in two years of work. In general on ekpluatatsionny qualities Tom on the standard international classification satisfies to modern standards of DOT-3 - it is a mass, "shirpotrebny" class without any special restrictions on application.

"Dew" – the product relating to the most perfect type. The main component – boron-containing polyair along with additives of a special purpose. Color – from light yellow to light brown. Indicators of boiling are as follows: in a "dry" look – 260 °C, in "humidified" – 165 °C, at the same time the critical indicator (150 °C) is reached only after three years of finding of liquid in a hydraulic actuator of the brake system. According to the international classification "Dew" satisfies with everything to norms of the class DOT-4 what is for today 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 a set of import brake fluids (Brake Fluid). If such liquid is recommended by the manufacturer for any cars and at the same time has marking of DOT-3 or DOT-4, then it can be used equally both in foreign cars, and in domestic cars. As for operational qualities, when comparing in the corresponding class (DOT-3 or DOT-4) import liquids are approximately identical to our Tom or "Dew" and have no special differences from them.