Brake fluid testing

Brake fluid is hygroscopy so it may be contaminated by water. To test if the brake fluid in a vehicle has been contaminated we use a Brake fluid tester which has three different coloured LEDs in it. If the green light goes on then the fluid is not contaminated, if the yellow light goes on it means it has been contaminated but it is still fine to use, if the red light goes on it means that the fluid is contaminated and will need to be replaced. Brake fluid does not stay uncontaminated and will need to replace about every two or less depending on the climate of the country the vehicle is in. When the brake fluid is contaminated the water brings the boiling point of it down and it could cause components in the system to corrode.

The vehicle that I tested showed a green light which meant that the fluid was fine and it did not need to be replaced. If the brake fluid needs replacing then drain all the the fluid out of the reservoir and put new fluid in then start bleeding the brakes on the wheel furthest away from  the master cylinder. Put a piece of wood under the brake pedal and get someone to pump it and then hold it down once they hold it down open the bleeder nipple and allow the brake fluid to escape into an allocated container then close it again. Repeat this until you can see that the new fluid is coming through then do it on the next wheel furthest away from the master cylinder. Do it until all of the fluid is out of the system and make sure that there is always enough fluid in the reservoir.