DOT 5.1 brake fluid

DOT 5.1 brake fluid: DOT 5.1 Motor Vehicle Brake Fluid offers improved performance over DOT standards and is designed to handle the most extreme braking situations. Formulated to prevent overheating and brake fade with a formula that exceeds DOT standards.

Synthetic formulation based on glycol ethers, alkyl polyglycols and glycol ether esters that guarantees complete performance even under extreme conditions. A higher wet and dry boiling point compared to DOT 3 and DOT 4 brake fluids and unique inhibitors provide protection against high temperature corrosion and oxidation. Special scavengers are used to suppress vapor at elevated humidity levels.

  • High performance formula for extreme braking like racing.
  • Prevent overheating and brake fade with our highest quality formula. Prevents corrosion of all metals within the braking system.
  • Superior protection in extreme braking conditions.

Fluid Background

Brake fluid, which is a hydraulic fluid, is responsible for moving the components of your bike’s brake system. Without this fluid, which works at both high temperature and high pressure, your bike would not be able to stop when you brake. Brake fluid pressure causes the brake pads to squeeze the disc, which slows and eventually stops the wheel from spinning.

Early brake fluids contained castor oil-based hydraulic fluids and alcohols such as butanol and ethanol. These fluids were used before brake fluid regulations were established, and it is the DOT 2 standard that provides these oil-based brake fluids.

The DOT by which the different types of brake fluid are identified comes from the US Department of Transportation (DoT) which classifies brake fluid.

After castor oil-based brake fluids came glycol-based fluids that meet DOT 3, 4, and 5.1 standards. After these glycol-based fluids came silicone-based fluids that generally meet DOT 5 standards, although they are not as widely used as glycol-based brake fluids.

There are three essential measurements used to establish a fluid’s final DOT classification that consumers should be aware of:

  • Moisture Resistance
  • Heat
  • Viscosity

The ability (or lack of ability) of your brake fluid to resist heat damage and Moisture has a significant impact on your performance, and consequently, on the performance of your bike’s braking system.

Implications of DOT Ratings

A brake fluid’s DOT number will give you an idea of ​​how the fluid will perform at the high temperatures generated by constant hard braking or in the most extreme weather temperatures.

For most motorcycle uses, you only need to be concerned with DOT 4 and DOT 5.1, and it is probably one of these fluids that is recommended for your motorcycle.

Since DOT 5.1 is more hygroscopic than DOT 4 and therefore absorbs more moisture, it will need to be changed more frequently. However, the benefit of 5.1 with its higher boiling point is that it can experience higher temperatures than DOT 4 before it starts to affect braking efficiency.

However, a good quality DOT 4 fluid like Super DOT4 that has a dry boiling point that exceeds the 5.1 minimum will be able to handle the temperature levels you would experience on a track day, for example. Super DOT4, like DOT 5.1, will need to be changed more frequently than DOT4 with the obvious budgetary implications.

DOT 5.1 maintains a lower viscosity at lower temperatures than DOT 4 down to around -40 degrees C, although this is unlikely to be relevant in the UK. For this reason, DOT4 is often a suitable brake fluid choice and requires less frequent changes.

Fluid Change Frequency

Hygroscopic brake fluids should be changed every 1-2 years due to increased water content due to moisture absorption. As a general rule of thumb, the higher the DOT number, the higher the absorption rate and therefore the more often the fluid will need to be changed.

DOT 5 brake fluid is not hygroscopic and therefore does not have to be replaced due to increasing water content. As a general rule, silicone fluid should only be used to fill systems that have not been previously filled with glycol-based fluid. A system that has used glycol based fluid (DOT 3/4/5.1) will inevitably contain moisture and glycol fluid disperses this moisture throughout the system and contains corrosion inhibitors.

Silicone fluid, on the other hand, does not allow moisture to enter the system, but it also does not disperse what is already in the system. A system that has been filled from dry with DOT 5 silicone fluid does not require changing the fluid at regular intervals, but only when the system has been disturbed by component repair or refurbishment. The use of silicone fluid is higher in cold climates due to its viscosity performance. 

Brake fluids that have different DOT classifications cannot always be mixed. DOT 5, for example, should never be mixed with the glycol ether component of DOT 3, 4 and 5.1, as the combination with a silicone fluid can cause corrosion due to trapped moisture. DOT 2 should never be mixed with any other brake fluid. Since DOT 3, DOT 4 and DOT 5.1 are based on glycol esters, they can be mixed.

However, the motorcycle manufacturer will state which brake fluid to use in the manual and while it is possible to upgrade to a higher performance brake fluid, ie DOT 4 to 5.1, you should never go below the manufacturer’s recommendation. Many fluid manufacturers recommend against mixing brands and DOT ratings because some chemicals may not be compatible. It is advisable that before adding brake fluid you check the stickers or warnings on your bike for additional information.

Another tip when changing your brake fluid is to always use fresh fluid from an unopened bottle so you can be on the safe side. will not be contaminated with water. Also remember that glycol ether based brake fluid will damage the paint on your bike if it comes in contact with it. DOT-5, being silicone-based, does not harm paint, although if spilled on paint, touch-up or repair may be difficult. Harley-Davidson used DOT 5 until all their bikes had ABS installed, at which point they specified DOT 4, the standard brake fluid today.

Play it safe with your brake fluid: change it regularly

  • Brake fluid in good condition is crucial for optimal brake performance
  • ZF Aftermarket experts recommend replacing it at regular intervals
  • Brake fluid change minimizes corrosion Brake

quality Brake fluid is crucial for optimal brake performance. The more water that has entered the brake fluid system over time, the faster the boiling point of the brake fluid is reached, leading to vapor bubbles and, in the worst case, total brake system failure. . Therefore, ZF Aftermarket experts recommend that workshop partners raise awareness on this topic and encourage their customers to change the fluid regularly. Manufacturers recommend annual replacement of DOT 3 brake fluids, which are often found in older vehicles, and that DOT 4 and DOT 5.1 fluids be changed at least every two years.

Drivers fear “hitting the void”: stepping on the brake pedal, feeling no resistance, and not experiencing the expected braking effect. This scary scenario could be caused by the condition of your brake fluid. Depending on the type and duration of use, the properties of the fluid may change, reducing its effectiveness. ZF Aftermarket experts have helpful tips on how to check the current condition of the brake fluid quickly and reliably. With these, workshops can offer their customers a wider range of services; helping to contribute to safer driving.

Severe overheating can cause total failure

Brake fluid fills a tube that connects the brake pedal to the pistons of the disc brake or the brake cylinders of the drum brake. When the pedal is depressed, the fluid transfers the pressure and thus supports the effect of the brake booster and ultimately the actual braking action. Various influences can greatly affect the condition of the fluid over time.

For example, severe overheating from applying the brakes on a long grade can cause the boiling point of the fluid to be exceeded. The result is an evaporation reaction, which in turn can lead to the formation of bubbles. When the pedal is depressed again, the air bubbles are compressed, but the braking force is greatly reduced and, in some cases, not transmitted at all. The lack of power transmission ultimately leads to brake failure.

Another reason for a faulty braking effect can be the ingress of water into the braking circuit. The weak point here is often the vent hole in the booster tank cap, which provides the necessary atmospheric ventilation in the event of fluctuating brake fluid levels. However, moisture from the air can also be sucked in through this ventilation hole. Also, water can enter the overcapacity tank through the vent when the engine is washed or the vehicle is cleaned.

Brake hoses and sealing elements can also be responsible for increased water content in brake fluid, as water can diffuse through them. Experience has shown the importance of this issue: ZF Aftermarket TRW brand experts estimate that the water content of three out of five vehicles currently in operation exceeds the recommended safety limits.

Too much water in the brake fluid also causes corrosion in the brake system. Brake pipes, pistons and cylinders must be replaced at high cost. Regularly changing the brake fluid saves the driver money.

If you find this post on DOT 5.1 brake fluid helpful to you and you want to know more about car fluid knowledge, please check more on our website Auto Oil And Fluid. Thank you for your interest!



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