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Synthetic Oil Experts in Akron, Ohio

Like AMSOIL Synthetic Motor Oil, AMSOIL Brake Fluid is an essential part of the hydraulic braking system. Without it, or without enough if it, the forces you apply at the brake lever would not be transferred to the calliper, pads and rotor. You wouldn't be able to stop your vehicle.

Hydraulic brakes are designed to use one of two main types of brake fluid, DOT fluid or Mineral Oil, and which one you pick is not a choice made by you or me, but rather by the brake manufacturers themselves. The question remains, "Which brake fluid is best and why do we have two to begin with?"

Let's explore these brake fluids in detail, sum up their advantages and disadvantages and explain why the experts believe their choice of fluid best for us riders is AMSOIL Synthetic Oil and lubricants. Let's get started Akron!

Brake Fluid's Role

Brakes slow us down by turning kinetic energy into heat by using friction. Brake fluid is only one of several vital components which enable hydraulic brake systems to work effectively. Its job is to transfer the input forces you create at the master cylinder (lever) to the calliper pistons. This is possible as fluids are incompressible. The brake fluid also has to resist, as far as possible, the high temperatures created by the braking forces.

DOT Fluid

Certainly the most commonly used brake fluid in use today is DOT fluid. All DOT fluids (with the exception of DOT 5) are made up of a poly-glycol base like AMSOIL Series 500 High-Performance DOT 3 Brake Fluid. Glycol-based fluids consist of a mixture of ingredients with as many as ten separate substances making up the final product. 

These substances can be broken down into four key components:
  • A lubricant, such as polyethene or polypropylene, to keep parts moving freely - 20-40%.
  • A solvent diluent, usually glycol ether, which determines the fluid's boiling point and viscosity and accounts for 50-80% of the fluid.
  • A modifier-coupler, which changes the amount of swelling of exposed rubber parts.
  • Inhibitors, to prevent corrosion and oxidisation.
DOT brake fluid is required to meet strict standards and specifications set out by the Society of Automotive Engineers and the Department of Transportation (DOT). These standards centre around maintaining brake fluid performance in a range of temperatures (high and low) and also specify the minimum boiling temperatures that the fluid manufacturers must adhere to.

Boiling Temperatures

One of the main differences separating the various classes of DOT fluid is their boiling temperature or boiling point. This refers to the temperature where the brake fluid will start to boil or vapourise inside the brake system. This is caused by the intense heat created by prolonged, heavy brake use and has an adverse effect on the performance of the entire brake system.

When brake fluid absorbs enough heat it boils and vapourises. It turns from a fluid into a gas. This gas can lead to complete brake failure in hydraulic systems. Suddenly the incompressible nature of the brake fluid, which produces the firm lever feel that we know and trust, has disappeared due to the introduction of compressible gases in the brake system.

Now all of the input forces normally created by squeezing the brake lever are lost as they go into compressing the air bubbles within the fluid instead. The brake fluid can no longer transfer these forces to the calliper leading to brake failure. This is known as 'fluid fade'.

Dry and Wet Boiling Points

The Dry Boiling Point of brake fluid refers to the boiling temperature of fresh, new brake fluid from an unopened container. Whereas the Wet Boiling Point is defined as the temperature DOT brake fluid will begin to boil after it has absorbed 3.7% water by volume. DOT brake fluid will reach this level of water volume after roughly two years of service, which is why it is advisable to renew your brake fluid every year. The Department of Transportation specifies the minimum wet boiling point of DOT brake fluids after absorbing only 3.7% water content (roughly two years service).

Glycol based fluids are hygroscopic which means they absorb water/moisture from the environment at normal atmospheric pressures at a rate of 2-3% per year. This process is exasperated in more humid conditions and climates.

This water content finds it's way into the brake fluid via microscopic pores in brake hoses, seals, joints and seams. Water mixed with DOT fluid has an adverse effect on the brake fluid by reducing it's boiling temperature and, therefore, reducing its performance.

Water Isn't All Bad

The hygroscopic nature of DOT brake fluid is an advantage in a major way. As water enters the system, instead of pooling in low spots (such as the calliper), due to its weight in comparison with brake fluid, it is dispersed throughout the whole of the brake fluid. This helps to keep the boiling point of the entire brake fluid high rather than having pools of water in the system which will boil much sooner than the rest of the brake fluid. It also prevents localised corrosion of internal parts that can be caused by water pooling in the brake system.

DOT 5 brake fluid

DOT 5 brake fluid is fundamentally different than the rest of the DOT fluid range in that it is silicone based brake fluid. It was originally introduced to give a higher boiling temperature over glycol-based products such as AMSOIL Series 600 DOT 4 Racing Brake Fluid. Purple in colour, DOT 5 is not compatible with any of the glycol-ether based DOT fluids. It is also more compressible than the other DOT brake fluids that can lead to a sluggish or spongy brake lever (or pedal) feel, and, therefore, requires special design considerations when used in brake systems. DOT 5 is hydrophobic and does not absorb water from the atmosphere like regular DOT brake fluid will. Due to its hydrophobic properties it has a very long lifespan meaning low maintenance and fewer fluid changes. A good example of its use is in military vehicles that can be stored for long periods of time but need to be ready to be used at a moment's notice. It is also favoured by some owners of classic cars for vehicles which may also rarely be used on the roads.

The Main Problem with Mineral Oil

Unlike DOT brake fluid, Mineral Oil Brake fluids are not governed by any standards or regulatory body. Therefore, the technical information on the various substances that contribute to their make-up is usually hard to come by.

Mineral Oil is hydrophobic and does not absorb moisture from the environment. Any water that does enter the brake system, via seals or microscopic pores in the lines, will effectively reduce the boiling point of the whole brake system to that of water - just 100°C. This is because as the fluid repels any water ingress, it causes it to pool at low points within the brake system, usually the calliper, since water is heavier than brake fluid it will settle at the lowest point. This is worrying because the fluid in the calliper is more susceptible to high temperatures as it's at the business end of the brake, where the friction is created.

DOT Brake Fluid Shelf Life

The shelf life of glycol-based DOT brake fluid is low due to its hygroscopic properties, which is why every bottle should come with an air tight foil liner covering the opening. As soon as this air tight seal is broken, it will start absorbing moisture from the environment and the boiling point will begin to drop.

DOT fluid in previously opened containers should be discarded after 12 months. It would be unwise to use DOT fluid from a bottle that has been open for more than a few months unless you have no other alternative. To reduce large quantities of wasted brake fluid, use DOT fluid from smaller 100ml bottles. 100ml is enough to bleed a set of brakes (front and rear) 2-3 times.

Brilliant Brake Fluid in Akron

AMSOIL Brake Fluid is a sensational requirement of a modern car. Brake Fluid is a high-performance non-petroleum brake and clutch fluid, suitable for all Hydraulic braking system like the disc, drum, ABS and clutches. It is Suitable for all rubber like Natural, SBR, EPDM, and Silicon, etc. AMSOIL Synthetic Oil and lubricants have a longer life and are more resistant to moisture and corrosion compared to conventional oil products. 

AMSOIL Brake Fluids supercede the specifications of SAE J 1703, 116 FMVSS 3 Brake DOT Fluid, 4 Brake DOT Fluid, and Silicon Brake Fluid. By offering quick response to pressure & pulses and low temperature stable, flowable upto-50ºC, AMSOIL Brake Fluid stays resistant to evaporation at high temperatures as well as resistant to the oxidation at high temperature. The quality of AMSOIL Brake Fluid does not deteriorate by moisture absorption. 

By using a non-silicon, glycol ether/poly glycols based product, AMSOIL Brake Fluid possess maximum hydraulic efficiency and lubricity. AMSOIL Brake Fluid complies with international specification as per its specified standards and absorbs less moisture at a slower rate to maintain a higher vapor lock or boiling point for longer time. It's also compatible with all suitable brake fluid based on glycol ether as it does not decompose.

 Jim Allen (877) 777-1645

 6715 River Corners Rd
Spencer, OH 44275 
United States
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