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BW05 brake fluid tester
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BW05 brake fluid tester

Digital inspection of the water content in brake fluid

Suitable for cars, motorcycles and trucks

Whether used in a car workshop or at home in your garage: the easily manageable brake fluid tester BW05 is the perfect measuring device for quickly and precisely determining the water content in a vehicle's brake fluid. The BW05 serves to check the three most important types of brake fluid DOT3, DOT4 and DOT5.1 and, what is more, conceivably easy to use:

Having selected the test mode for the respective type of brake fluid, the sensors of the digital measuring device can be dipped into the fluid. Based on the traffic light principle three colour LEDs indicate the water percentage result in a matter of only a few seconds (see graph): Green light suggests that you are all set and ready to go, since the share of water amounts to less than 1.5 %. Yellow signifies that you may proceed with your journey, but should frequently reexamine the water content that is already between 1.5 and 3 %. And with more than 3 % the red light denotes the immediate necessity of exchanging the brake fluid to prevent a failure of the hydraulic braking system

At the end of the check-up switch the BW05 off, clean the sensors with a dry cloth and store the measuring device in a dry location until it is needed again. Should you forget to switch the device off by hand, no need to worry: the tester switches off automatically after a period of 20 seconds.

Caution! Risk of brake failure with a water content of 3 per cent

Brake fluid is hygroscopic, this means that – even though it flows through a closed circuit – water is absorbed from the humid air.

In minor quantities, to be sure, but it is a continuous process, so the fluid will be gradually diluted over time: Starting at a water content of three per cent it might be best to ditch your car or motorcycle for the time being, seeing as the brake fluid's boiling point decreases dangerously which can lead to overheating, the formation of vapour bubbles and a virtually absent braking effect.

Moreover, the elevated water percentage also increases the risk of corrosion within the entire braking system – right up to the point of seizing. 

It would therefore be advisable to perform regular inspections of the brake fluid using the BW05 for any type of vehicle or machine fitted with a hydraulic braking system – especially in case of older vehicles or those that are only rarely used a recurring examinations are inevitable.

BW05 – Special equipment features

BW05 brake fluid tester
BW05 brake fluid tester
Compact design in pen form with pocket clip
BW05 brake fluid tester
Power supply: 3 x 1.5 V, LR44
BW05 brake fluid tester
Simple application

Application examples from practical experience:

BW05 – Brake fluid inspection for motorcycles
The red LED indicates that the brake fluid of this motorcycle should be exchanged as soon as possible.
BW05 – Brake fluid inspection for cars
A green LED during the brake fluid inspection indicates nothing to prevent a safe journey – the car is ready to go.
Measuring devices for liquid analysis

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Technical data by comparison

A few practical benefits:

  • Suitable for cars, motorcycles and trucks 
  • Checking the water concentration in brake fluids of type DOT3, DOT4 and DOT5.1 in a matter of seconds 
  • Self-explanatory LED status indication based on the traffic light principle
  • Simple application
  • No expert knowledge required
  • Compact pen-shaped design with pocket clip 
  • Battery change indicator
  • Automatic switch-off

 standard equipment

 optionally available

 not available


BW05 Bremsflüssigkeitstester show in Trotec online shop

Technical data

Technical data
General information
  Article number 3.510.205.805
Brake fluids
  Brake fluids DOT3, DOT4, DOT5.1
Power supply
  Battery type 3 x 1.5 V, LR44
Ambient conditions
  Operation - min. temperature [°C] 0
  Operation - max. temperature [°C] 40
  Operation - max. relative humidity [% r.F.] 80
  Storage - min. temperature [°C] -10
  Storage - max. temperature [°C] 50
  Storage - max. relative humidity [% r.F.] 80
Standard scope of delivery
Standard scope of delivery
  Measuring device
  Operating manual
Ascertainable measured values and functions
Functions and features
  Brake fluid test for DOT3, DOT4 and DOT5.1 (traffic light principle)
  Visual alarm
  Automatic switch-off
  Automatic battery test

 standard equipment

 optionally available

 not available

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