Brake Fluid Testing Machines

[sarah_louise]

My garage dont change the brake fluid every two years as it says in the handbook. They say they test it.
This fluid is not circulated through the reservoir so is constantly changing between high and low pressure, when braking and then the release of the pedal. Also, if excessive heat is passed from the brake discs and pads through to the fluid in the pipes surely it is no good measuring what’s in the reservoir?
Any experts have an opinion please.

[Toureman]

They are not testing for heat.

They are testing for moisture content.

[Nkakamasembe]

When a car manufacturer recommends brake fluid change after 2 years,the car might has well moved only 10 miles.
The brake fluid absorbs moisture from atmosphere so after 2 years it would have deteriorated to a point where its losses it properties eg boiling point etc.among many others.

[sarah_louise]

Yes I understand they are not measuring heat but moisture content. As the second answer explained it is the heat that causes braking problems.
Thank you.
I wonder why the garage thinks this is satisfactory ?
Just too much trouble to do ?

[sarah_louise]

Toureman. What are the units of measurement and what is the acceptable limit then ?
A Standard Quality Assurance Procedure would demand this ?

[AlBags]

The biggest problem is .. (and I know a couple of places that use this as a method to make more money) a few garages will charge you full retail cost plus some time to hike the bill up more. Many will not even actually test it.
If they say they need to change it, simply ask them to show you the testing device.
Any other method used to determine is just speculation and/or "estimation" of it's degradation.