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Video Brakes
Video Single-circuit System
Video Dual-circuit Brake
Video Disc Brake
Video Turning Brake-discs
Video Disc parking brake
Video Drum Brake 1
Video Drum Brake 2
Video Drum Brake 3
Video Engine Brake
Video Master Cylinder 1
Video Master Cylinder 2
Video Brake Pad
Video Brake Pad 2
Video Brake Pad 3
Video Brake Fluid 1
Video Brake Fluid 2
Video Brake Servo
Video Brake assist system
Video Electr. Brake Servo
Video ABS 1
Video ABS 2
Video ABS 3
Video ABS 4
Video ABS/ESP-Hydr. Unit
Video ESP 2
Video Wheel sensor 1
Video Wheel sensor 2
Video Parking Brake
Video Overrun Brake 1
Video Overrun Brake 2
Video Brake recuperation 1
Video Brake recuperation 2
Video Brake recuperation 3
Video Elektro-hydr. Brake 1
Video Elektro-hydr. Brake 2
Video Calliper (electr. brake)
Video Brake Test Stand 1
Video Brake Test Stand 2
Video Floating Brake
Video Sliding-calliper 1
Video Sliding-calliper 2
Video Sliding-calliper 3
Video Sliding-calliper 4
Video Brake doesn't release
Video Disc-brake Caliper
Video Disc brake failure 1
Video Disc brake failure 2
Video Fixed-calliper 1
Video Fixed-calliper 2B
Video Fixed-calliper 3
Video Parking Brake 1
Video Parking Brake 2
Video Parking Brake 3
Video Parking Brake 4
Video Carbon Brake Disc
Video Ventilated Disc 1
Video Ventilated Disc 2

Video Compressed Air Brake 1
Video Compressed Air Brake 2
Video Electr. Compr. Air Brake
Video Driving Preparation
Video Drum Brake (truck) 1
Video Drum Brake (truck) 2
Video Drum Brake (truck) 3
Video Drum Brake (truck) 4
Video Disc Brake (truck) 1
Video Disk Brake (truck) 2
Video Trailer Brake System
Video Handbrake
Video Brake-air Compressor
Video Water-drainage
Video Air Dryer
Video Pressure Regulator
Video Four-circuit Protection
Video Dual-circuit Brake
Video ALB Regulator
Video Diaphragm Cylinder 1
Video Spring-type Cylinder 1
Video Spring-type Cylinder 2

Video Force (brake)
Video Distance (brake)
Video Time (brake)
Video Brake (pedal-force)

Video Brake (general) 1
Video Brake (general) 2
Video Hydraulic brake 1
Video Pneum. Brake 1
Video Pneum. Brake 2

          A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Brake Fluid

Slightly hygroscopic
Resistant to aging
Neutral (metal, rubber)
High wet boiling point
Low pour point
Low compressibility
Constant compressibility

The wet boiling point is measured at a 3,5% water-content.

The brake fluid should, through a high (wet) boiling point, a low solidifying point and a constant viscosity, through a large range of temperature, transfer the pressure from the main brake cylinder to the wheel brake cylinders. Whereby, the regulation systems (e.g. ABS.) must also still function at low temperatures. The solidifying point of brake fluid lies at below -65C.

Keep mineral oil away from the brake hydraulics!

Brake fluid is made up of polyglycol compounds and sometimes also silicone fluid. In comparison with motor-oil there are considerable differences. The two substances may not be mixed with each other when disposing of them. Due to the fact that the brakes can become hotter than the engine, the brake fluid must be particularly protected against the development of steam bubbles. Unfortunately, it is prone to taking on water (hygroscopic), which lowers it's wet boiling point and if it's not changed at adequate intervals, can possibly cause a complete braking system failure.

Brake fluid is toxic and attacks the paintwork.

Water primarily penetrates the hydraulic system through the brake hoses and the rubber gaiters when releasing the brakes. This is just one reason why the brake fluid must be regularly changed. At the same time, some of the abrasion debris from the seals is possibly rinsed out. Should one not be prepared to observe the regular replacement intervals, one can use a suitable tester to help ascertain the moisture content. Water is also largely responsible for internal corrosion.

The flexible tubes/piping should be replaced regularly.

Brake pipes- and hoses mostly undergo an optical check-up. Of course, a long-time pressure test is also possible. The pipes can leave their mountings, they can chafe, be corroded and, particularly at their connection points, be leaky. One can bend the flexible tubes to be able to better recognise surface cracks. When the springs are compressed and when steering, one must make sure that the tubes have no contact with foreign bodies. Not only are they susceptible to exterior damage, taking the increasing age of the vehicle and/or the amount of time that the vehicle has not been in use, they are prone to swelling, right up to the point where they are completely blocked.

Brake-line checking is vital.

Should you be of the opinion that check-ups are not all that important because, after all, there is a second brake-circuit available, then please, don't underestimate the shock you will get when you press the brake pedal, and nothing happens. You will forfeit several meters of braking distance which cannot be compensated for by the function of only two wheel brakes, not to mention that the car will pull strongly to one side.

Lowest permissable boiling point temperature
in Germany:

Unfortunately, the acceptance of the brake fluid change has suffered somewhat because vehicle owners felt that arbitrary and too frequent changes were being carried out. Ever since brake fluid can be tested, these problems can be considered as settled. The device shown above gives the boiling point of the brake fluid tested and thus, allows a clear picture of the state of the liquid. 04/13

Brake fluid
Highly durable -> silicon based
Otherwise polyethylene und glycol (95 %) (95 %)
Not mixable with each other.               Top of page               Index
2001-2015 Copyright programs, texts, animations, pictures: H. Huppertz - E-Mail
Translator: Don Leslie - Email:

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