K Services can offer you a mobile brake fluid change. It is essential as brake fluid, over time, takes in water which makes your brakes less efficient. We recommend changing your brake fluid on a major service or at least every two years.
Brake fluid plays a critical function within a hydraulic system. Still, it can often become overlooked and then becomes a much more complex operation. It is essential to accurately measure the water content of glycol-based brake fluid, known for its ability to absorb humidity from the air. It has been an essential part of MOT inspections since 2018. Knowing the difference between DOT 3 and DOT 5 brake fluids is thus crucial.
Why water can be a problem
Manufacturers' data generally gives a 24-month lifespan for common-use brake fluid; factors such as the age of the vehicle, changes in ownership, and events such as a pandemic can lead to a disruption in the necessary cycle of alteration.
When the water content is high, it speeds up the system's decomposition. The ice expansion can weaken its stability. When the brakes are used, the heat generated can cause the liquid to evaporate, resulting in pockets of gas that render the hydraulic system unable to function.
Take a visual check
Brake fluid is checked during the MOT for level and contamination. It is not allowed to take off the brake fluid reservoir cap, and this inspection process may be challenged due to older vehicles. Contamination of the brake fluid, which may appear as the colour of cola, is obvious to detect. Nevertheless, only the most severe cases will be given a reason for refusal.
A visual inspection during routine maintenance doesn't have this restriction, but if you take the cap off, testing the fluid is advisable as usual, straw-coloured brake fluid may still have a high-water content.
Get the measurements right
There are two standard methods to measure the water content in brake fluid. One uses a dip-style pen device with a traffic light LED display to indicate the approximate water content. This economical solution doesn't remove any fluid from the reservoir.
The second method involves taking a sample of the brake fluid and boiling it to measure its boiling point accurately. This requires specialized and expensive equipment, making it a costly choice. However, the high level of accuracy that comes with this method may make the cost worthwhile.
Fluid exchange
In the past, when someone wanted to change the brake fluid, they had to enlist the help of a second person to physically step on the brake pedal while each line was drained of fluid. This technique is still sometimes used in older cars, but newer models require specialized equipment to perform the task.
The benefit of this is that it becomes a single-person process. It is necessary for modern systems such as pressure and diagnostic tool to remove any air and residue. If neglected, this can lead to parts such as the ABS module malfunctioning.
Although this process may be quicker, it can be more costly due to the more significant expense of the necessary tools, the upkeep of the machinery, and the need to frequently update the database for newer cars.
Referencing the manufacturer's information is essential for selecting the correct brake fluid (different types should not be mixed) and for the prescribed technique for change.
It is not advised to attempt a manual process for a brake system that requires special diagnostic tools and/or a pressure bleeder using only one person. However, a one-person operation utilizing a pressure bleeder may be possible for older brake systems.
And in the age of electrification, it's worth remembering that some high-voltage vehicles may use regenerative braking, meaning there could be two hydraulic systems to bleed.
Common brake fluids and their wet boiling points
Different types of brake fluids are available, all of which are based on glycol. The highest temperatures are DOT 3 (140°C) and DOT 4 (155°C). Even higher temperature brake fluids are DOT 5.1 (185°C) and Super DOT 4 (195°C). Additionally, DOT 5 is a silicone-based brake fluid operating at a temperature of 185°C.rocess for a brake system that requires special diagnostic tools and/or a pressure bleeder using only one person. However, a one-person operation utilizing a pressure bleeder may be possible for older brake systems.
And in the age of electrification, it's worth remembering that some high-voltage vehicles may use regenerative braking, meaning there could be two hydraulic systems to bleed.
Symptoms of air in the brake system
- Spongey brake pedal
- Imbalance
- Methods of inspection
K Services can offer you a mobile brake fluid change. It is essential as brake fluid, over time, takes in water which makes your brakes less efficient. We recommend changing your brake fluid on a major service or at least every two years.
Brake fluid plays a critical function within a hydraulic system. Still, it can often become overlooked and then becomes a much more complex operation. It is essential to accurately measure the water content of glycol-based brake fluid, known for its ability to absorb humidity from the air. It has been an essential part of MOT inspections since 2018. Knowing the difference between DOT 3 and DOT 5 brake fluids is thus crucial.
Why water can be a problem
Manufacturers' data generally gives a 24-month lifespan for common-use brake fluid; factors such as the age of the vehicle, changes in ownership, and events such as a pandemic can lead to a disruption in the necessary cycle of alteration.
When the water content is high, it speeds up the system's decomposition. The ice expansion can weaken its stability. When the brakes are used, the heat generated can cause the liquid to evaporate, resulting in pockets of gas that render the hydraulic system unable to function.
Take a visual check
Brake fluid is checked during the MOT for level and contamination. It is not allowed to take off the brake fluid reservoir cap, and this inspection process may be challenged due to older vehicles. Contamination of the brake fluid, which may appear as the colour of cola, is obvious to detect. Nevertheless, only the most severe cases will be given a reason for refusal.
A visual inspection during routine maintenance doesn't have this restriction, but if you take the cap off, testing the fluid is advisable as usual, straw-coloured brake fluid may still have a high-water content.
Get the measurements right
There are two standard methods to measure the water content in brake fluid. One uses a dip-style pen device with a traffic light LED display to indicate the approximate water content. This economical solution doesn't remove any fluid from the reservoir.
The second method involves taking a sample of the brake fluid and boiling it to measure its boiling point accurately. This requires specialized and expensive equipment, making it a costly choice. However, the high level of accuracy that comes with this method may make the cost worthwhile.
Fluid exchange
In the past, when someone wanted to change the brake fluid, they had to enlist the help of a second person to physically step on the brake pedal while each line was drained of fluid. This technique is still sometimes used in older cars, but newer models require specialized equipment to perform the task.
The benefit of this is that it becomes a single-person process. It is necessary for modern systems such as pressure and diagnostic tool to remove any air and residue. If neglected, this can lead to parts such as the ABS module malfunctioning.
Although this process may be quicker, it can be more costly due to the more significant expense of the necessary tools, the upkeep of the machinery, and the need to frequently update the database for newer cars.
Referencing the manufacturer's information is essential for selecting the correct brake fluid (different types should not be mixed) and for the prescribed technique for change.
It is not advised to attempt a manual process for a brake system that requires special diagnostic tools and/or a pressure bleeder using only one person. However, a one-person operation utilizing a pressure bleeder may be possible for older brake systems.
And in the age of electrification, it's worth remembering that some high-voltage vehicles may use regenerative braking, meaning there could be two hydraulic systems to bleed.
Common brake fluids and their wet boiling points
Different types of brake fluids are available, all of which are based on glycol. The highest temperatures are DOT 3 (140°C) and DOT 4 (155°C). Even higher temperature brake fluids are DOT 5.1 (185°C) and Super DOT 4 (195°C). Additionally, DOT 5 is a silicone-based brake fluid operating at a temperature of 185°C.rocess for a brake system that requires special diagnostic tools and/or a pressure bleeder using only one person. However, a one-person operation utilizing a pressure bleeder may be possible for older brake systems.
And in the age of electrification, it's worth remembering that some high-voltage vehicles may use regenerative braking, meaning there could be two hydraulic systems to bleed.
Symptoms of air in the brake system
- Spongey brake pedal
- Imbalance
- Methods of inspection
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