When was the last time you changed your brake fluid?
Research has suggested that more than a quarter of all the cars in the UK have defective brake fluid.
Now you, like us, might raise an eyebrow at that statement. The research, carried out for Cosan Lubricants’ Mobil Car Care range, however, bears some consideration.
Brake fluid is hygroscopic, meaning that it absorbs water from the atmosphere. Over time this reduces its effectiveness by lowering its boiling point.
When the fluid boils, vapour is produced – which is compressible – resulting in a soft brake pedal and a decreased, or non-existent, braking effort.
Cosan says that brake fluid, which has a typical boiling point of between 230-260 degrees C when new, becomes all but useless once it boils below 180deg.
Brake fluid expert Alba Diagnostic concurs, suggesting that brake fluid should be changed when its boiling point is down to 200deg C — and it’s below this figure that the research suggests more than a quarter of all cars will boil their fluid.
After all, how many of us are particularly attentive as to what goes into our brake fluid reservoirs? We may intermittently check the levels, but few of us are likely to go any further.
Many of us use whatever brake fluid tends to be handy — which might be a contaminated bottle that’s been on the shelf for a while. That’s assuming, of course, that the fluid has even been changed in recent history.
Mike Bewsey, of Cosan Lubricants, said: "Many drivers mistakenly believe that if their car has passed its MOT, all of the lubricants and chemicals within it are up to scratch.
"The only way to check the quality of brake fluid is to test its boiling point temperature. As that is not part of the MOT, the onus is clearly on motorists to ensure that their car is safe."
So if you’ve only been intermittently checking your brake fluid’s levels, or don’t know when it was last refreshed, perhaps it’s time to consider a change. After all, for £100 including labour, it’s cheap insurance.
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