Comma Brake Fluid

What’s the Difference Between Brake Fluid Types?

Vital News speak to Comma about how brake fluid has evolved to stay up to date with advancing vehicle technology.

The ever-advancing technological demands and amenities of modern vehicles mean that they weigh more, accelerate harder and travel substantially faster than their older counterparts. Combined with complex, computer controlled functions such as anti-lock braking system (ABS) and the electronic stability programme (ESP), modern brake fluids have become more sophisticated in order to keep up.

Types of Brake Fluid Today

There is a wider range of brake fluids that meet the various demands of modern vehicles today.

Synthetic Fluids

Synthetic fluids based on polyalkylene glycol (PAG), are the most common types (DOT 3, DOT 4, DOT 4 ESP and DOT 5.1). They are compatible with one another and therefore can be mixed. However, as with oil and coolant, technicians should always comply with the manufacturers’ specifications for the intended vehicle as using the wrong fluid can seriously compromise braking performance.

Mineral Oil-Based

Comma’s LHM+ brake fluid is mineral oil based and has been used in Citroën combined hydraulic systems. It is specifically formulated for hydraulic systems and not suitable for use where DOT type fluids are specified.


Although marketed as DOT 5.0, it should not be confused with other DOT specified brake fluids. DOT 5.0 is silicone-based and formulated for specialist applications and therefore not part of the Comma range. It is not compatible with any other type of brake fluids and not recommended for conventional applications. Do not mix DOT 5.0 with other brake fluids as it can cause significant damage to the braking system.

The UK Vehicle Parc Currently Calls for the Following Types of Brake Fluids*

  • DOT 4
  • DOT 4 ESP
  • DOT 5.1
  • Specialist Fluids

*Based on the mid 2016 UK Parc figures

Why Do Different Formulas Exist?

As a safety critical aspect for all vehicles, the integrity of the braking system is non-negotiable. High performance brake fluids are an integral part of ensuring that vehicles brake safely and effectively. Modern vehicles have the ability to self-stabilise by detecting and reducing loss of traction with ESP.

As a result, brake systems should have an optimized response. This requires the brake fluid to have enhanced viscosity performances able to transmit the precise impulses of the system. Finally, today’s heavier and larger vehicles call for fluid with higher boiling points to avoid vaporising in the system.

With this in mind, it is important for factors to recognise that DOT 3 and DOT 4 brake fluids are no longer the only specifications needed by customers today.

When Should I Change Brake Fluid?

Manufacturers generally recommend changing the brake fluid at intervals of between 1 to 2 years. This is because, as brake fluid gets older, it continues to absorb more water that dangerously decreases the boiling point.

Water-contaminated brake fluid causes vapour bubbles to develop. This vapour is very compressible and absorbs large amounts of the force applied to the brake pedal before it ever reaches the calipers – making the brakes feel spongy.

Make the Right Choice with Comma

Comma has made choosing the right brake fluid for any car with the ‘Comma Oil Finder’ that is available for free download on Google Play and the Apple App Store. By using the VRN, users will be presented with a report of recommended products including engine oil, antifreeze & coolant, transmission oils, greases and brake fluid.

For more information, please speak with your local FPS representative.



If you have an account with FPS and would like more information on this article please get in touch with your local warehouse or Territory Manager, alternatively use our enquiry form.