Harleys are iconic motorcycles, and as a Harley-Davidson owner, you want to make sure you take the best possible care of your bike. One important maintenance aspect for any Harley-Davidson is the brake fluid. But with so many different types of brake fluid, it can be confusing to figure out which one is best for your Harley.
Most Harley-Davidson motorcycles use DOT 4 brake fluid, but it’s important to check the owner’s manual for your model’s specific requirement.
In this article, we’ll discuss the different types of brake fluid and the advantages and disadvantages of each, so you can make an informed decision about which type of brake fluid to use for your Harley-Davidson. We’ll also look at how often you should change the brake fluid in your Harley and what you’ll need to do it. So, if you’re a Harley-Davidson owner, read on to learn more about brake fluid and how to make sure your Harley is running at its best. Â
What is the Purpose of Brake Fluid?
When you’re riding your bike at high speeds, you’ll want to make sure that your brakes won’t let you down and that a braking failure doesn’t end up being the penultimate experience of your life. An essential part of your Harley-Davidson bike’s braking experience is the brake fluid. However, many bikers are unsure of the purpose of brake fluid and how it works. A lack of knowledge of brake fluids can be catastrophic to the biker.
Brake fluid plays a significant role in braking, as it helps in transferring the movement and force produced when you’re pressing down on the brake pedal. Extreme heat will get generated when braking. This high heat could cause moisture to condense in the brake hydraulic system. The brake fluid will absorb the moisture and prevent it from boiling and resulting in brake failure. Additionally, brake fluid will serve as a lubricant for all movable parts while also preventing corrosion. It needs to remain in a fluid form at all temperatures.
Brake fluid helps in transferring the movement and force created when you’re pressing down on the brake pedal. Generally, adding brake fluid is not part of routine Harley maintenance. Low brake fluid will typically mean that the brake pads are worn and will soon have to be changed. In case you notice a sudden drop in your bike’s brake fluid levels, it may indicate a problem with the brake system or that you simply have to change the brakes.
What are the Different Types of Brake Fluids?
The brake fluid plays a significant role in how the brakes in your Harley-Davidson bike function. There are different types of brake fluids available in the market, with some of them being glycol-based fluids while others are silicon-based. Another difference is that certain types of fluids absorb water while others do not.
Boiling point is one of the most important characteristics of brake fluid. Hydraulic systems rely on an incompressible fluid for transmitting force. Generally, liquids tend to be incompressible while gases are compressible. If the brake fluid boils or turns to gas, it will end up losing its ability to transmit force. This might partially or completely disable the bike’s brakes. For making matters worse, you will likely only boil the brake fluid during periods of prolonged braking, like when driving down a mountain. This is definitely not the best time for your bike’s brakes to fail.
If you weren’t aware of the brake fluids, here are the different types of brake fluids available on the market –
DOT 3
Glycol-based DOT 3 fluid tends to be the most widely used option on the current market. This brake fluid has been there on the market for quite a while. Despite its age, it still gets used widely thanks to its low cost-to-performance ratio. In that regard, the boiling point of fresh new DOT 3 brake fluid is no more than 205° C. However, if it gets damaged, it might resist temperatures as low as 140° C. If you fail to change the brake oil on time, it might cause the brake fluid to overheat, reducing your bike’s braking bite.
DOT 4
The DOT 4 is a slightly costlier option. This one also happens to be a glycol-based brake oil. However, the composition seems to be slightly different. Due to the unique composition, the DOT 4 brake fluid might resist temperatures as high as 230° C. Further, by adding certain chemicals, the buildup of moisture inside your bike can be prevented. Moreover, they are ideally suited for models that are quitted with ABS technology.
DOT 5
DOT 5 is a brake fluid that happens to be one of the more expensive braking fluids on the market. The fact that it is silicone-based happens to be the finest feature of this brake oil. Due to the chemical composition, this type of brake fluid might be able to withstand temperatures as high as 260° C. Another advantage of this particular brake oil is that it does not contain any moisture, as opposed to glycol-based brake fluids. However, DOT 5 brake fluid tends to have a number of drawbacks. Additionally, foam generation tends to be easier with brake oil, as these bubbles will be a lot more difficult to bleed than air.
DOT 5.1
The DOT 5.1 brake fluid is also one of the types of brake fluids capable of withstanding the greatest temperatures. On the other hand, this type of brake fluid is a combination of glycol ether and borate ester. In fact, it is capable of enduring temperatures as high as 260° C due to its complicated chemical composition. Further, this brake fluid also has certain qualities of DOT 4 and DOT 3. The most notable feature here is that it is hygroscopic. This means it is capable of absorbing moisture quite well.
While deciding on the type of brake fluid to purchase, the most rewarding advice would be to stick to the brake fluid that is on your bike. Even though a certain type of brake fluid has certain classifications, it doesn’t necessarily mean that it wouldn’t be able to offer equal or even better performances for your particular model than fluids having higher classifications.
The DOT 3 fluid may have a superior boiling point compared to the DOT 4 brake fluid based on its composition. However, it will all depend on your bike’s requirements. You need to make sure that you’re opting for the right type of brake fluid that suits your Harley-Davidson bike.
As DOT 3 and DOT 4 brake fluids absorb water, their boiling point tends to decrease. They can easily absorb water from the air, which is why you must avoid opening your bike’s brake fluid reservoir. For the same reason, you must always keep the containers of brake fluid sealed tightly. DOT 5 fluid, on the other hand, doesn’t absorb water. It means that the boiling point of the fluid remains relatively stable, but it also means that any water that enters the brake system will tend to form pure water pockets.
This can result in brake corrosion. The other important thing that you should remember about brake fluid is that DOT 3 and DOT 4 eat paint, so you shouldn’t spill either of them on your bike. Moreover, you shouldn’t mix different types of brake fluids, as they can react badly and end up corroding the brake system.
What Type of Brake Fluid Do Harley-Davidson Bikes Use?
Harley-Davidson bikes require a specific type of brake fluid to make sure they deliver optimal performance and safety. The recommended brake fluid for the brakes used in Harley-Davidson bikes is DOT 4 Synthetic Brake Fluid. This type of fluid offers superior performance in terms of both freezing point and boiling point. This helps in improving braking performance in extreme conditions. Moreover, DOT 4 synthetic brake fluid tends to have a higher moisture tolerance compared to the other fluids, which means that it can withstand exposure to moisture without degrading.
All older Harley-Davidson bikes from 1976 to 2005 used to feature DOT 5 brake fluid. However, you need to be careful with this type of fluid as you cannot mix it with other types as it isn’t glycol-based.
DOT 5 brake fluid is a synthetic brake fluid that is designed to be used in vehicles that need higher boiling points than DOT 3 and DOT 4 brake fluids. DOT 5 brake fluid is capable of withstanding higher temperatures without actually vaporizing. Harley-Davidson is one of the few motorcycle brands capable of using this type of brake fluid.
While DOT 5 fluid isn’t needed for all Harley-Davidson bikes, it can definitely benefit bikers who ride in hot weather or perform a lot of stop-and-go riding. This will make it ideal for high-performance applications where braking temperatures can be quite high. To know whether your Harley-Davidson bike uses DOT 5 fluid or not, you must consult the owner’s manual or get in touch with a service professional.
Key Factors to Consider When Selecting Brake Fluid for Harley-Davidson Bikes
When it comes to Harley-Davidson bikes, selecting the right brake fluid will be critical for ensuring optimum performance and safety. The brake system is an important part of any bike, and the fluid is what makes the brakes work properly. Therefore, choosing the right brake fluid for your Harley will be crucial to keep your motorcycle running safely and smoothly. Here are the key factors to consider when choosing brake fluid for your Harley-Davidson bike-Â
1. Type of brake system
The type of brake system on your Harley will determine the type of brake fluid you should go for. Harley-Davidson bikes typically come with either a hydraulic drum brake system or a hydraulic disc brake system. The hydraulic disc brake system makes use of DOT 4 brake fluid, whereas the hydraulic drum brake system utilizes DOT 5 brake fluid.
2. Temperature range
Another key factor to consider will be the temperature range of the brake fluid. Harley-Davidson bikes come designed to operate in a wide range of temperatures, and the brake fluid should be able to perform under those conditions. High-performance brake fluids are generally designed to withstand high temperatures, which can be beneficial for bikers who frequently ride in hot weather or use their motorcycles for racing or performance purposes.
3. Moisture resistance
Moisture can be a major enemy of brake fluid. It can cause the brake fluid to become contaminated and decrease the effectiveness of the brake system. Therefore, choosing a brake fluid that has moisture resistance will be essential. Many high-performance brake fluids in the market contain additives that help in preventing moisture from accumulating in your bike’s brake system.
4. Brand reputation
Choosing a reputable brand will be essential when selecting the brake fluid for your Harley. Reputable brands also come with a proven track record of producing high-quality brake fluids that meet industry standards and have been tested for safety and performance.
5. Compatibility
Lastly, it’ll be important that you ensure that the brake fluid you’ve chosen is compatible with your Harley-Davidson bike’s brake system. Using the wrong brake fluid can potentially lead to brake failure, while also compromising your safety on the road.
When to Flush and Replace the Brake Fluid for Harley-Davidson Bikes?
The brake system is one of the most important components of any Harley-Davidson motorcycle. The brake fluid in your Harley-Davidson bike plays a key role in keeping you safe on the road, as it’ll help transmit the force from the brake lever or pedal to the brake calipers.
Over time, the brake fluid in your Harley can become contaminated, which can potentially lead to decreased performance and even brake failure. Therefore, it’ll be important that you know when to flush and replace the brake fluid in your Harley-Davidson motorcycle. Here are the factors that you must consider when deciding when to flush and replace the brake fluid in your Harley-Davidson motorcycle –Â
1. Mileage and age
The mileage and age of your Harley-Davidson motorcycle are the essential factors to consider when deciding whether to flush and replace the brake fluid on your bike. As a general rule of thumb, it’s recommended that you must flush and replace the brake fluid once every two years, irrespective of mileage. However, if you frequently ride your bike in harsh conditions, such as dusty or wet environments, you might have to replace the brake fluid more frequently.
2. Changes in brake performance
If you notice changes in your motorcycle’s brake performance, such as a longer stopping distance or sponginess, it might be time to flush and replace the brake fluid. Contaminated brake fluid could result in the brake calipers working improperly, which leads to decreased brake performance. If you experience changes in your motorcycle’s braking ability, it’s important that you have it inspected by a professional.
3. Smell and appearance
Checking the smell and appearance of the brake fluid will be another way of determining whether it is time to replace the fluid. Brake fluid should ideally be clear and transparent, with no discoloration or particles. If you notice any discoloration or cloudiness, it might be a sign that the brake fluid has gotten contaminated. Moreover, if the brake fluid has a burnt or pungent smell, it might be the right time to flush and replace it.
4. Manufacturer recommendation
Lastly, it is essential that you follow the manufacturer’s recommendation for your Harley. Each model and year might have different recommendations for when you should flush and replace the brake fluid. It’s also important to consult the owner’s manual or talk to a professional mechanic to ensure that you are following the manufacturer’s guidelines.
How to Flush and Replace Brake Fluid for Harley-Davidson Bikes
The brake system is an important component of a Harley-Davidson bike. This critical part of the system transmits the force from the brake lever or pedal to the brake calipers. Over time, the brake fluid in your Harley-Davidson motorcycle can become contaminated, which can potentially lead to decreased performance and even brake failure.
The process to flush and replace the brake fluid in your Harley-Davidson bike is a rather straightforward maintenance task that you can carry out to keep your motorcycle running safely and smoothly. Here is how you can flush and replace the brake fluid in your Harley-Davidson motorcycle-
Step 1: Gather tools and materials
Before you start, you’ll first have to gather the tools and materials necessary for the task. Here is what you will need –
- Â Â Â Â Â Â Â Â A funnel
- Â Â Â Â Â Â Â Â A clean container for catching the old brake fluid
- Â Â Â Â Â Â Â Â Wrench or pliers
- Â Â Â Â Â Â Â Â A clean rag or towel
- Â Â Â Â Â Â Â Â The brake fluid recommended by the manufacturer
Step 2: Locate the brake bleeder valve
The next step in flushing and replacing the brake fluid in your Harley-Davidson motorcycle will be to locate the brake bleeder valve. The valve is generally located on the brake caliper, and it is easily identifiable by the small size and position on the caliper.
Step 3: Open the brake bleeder valve
With the help of a wrench or pliers, you must open the brake bleeder valve on your bike. This will allow the old brake fluid to easily drain out of the system. You should make sure that you place the clean container directly underneath the valve to catch the old brake fluid.
Step 4: Flush the system
Once the valve is open, you should slowly pump the brake lever or pedal until the old fluid gets completely drained out of the system. It is important that you pump the lever or pedal slowly and steadily so that you can avoid damaging the brake system.
Step 5: Refill the system
Once you have completely drained out the brake fluid from your bike, refill the system with the recommended brake fluid. You should make sure that you’re using a funnel for avoiding spilling the fluid. You must fill the system until the fluid has reached the maximum level indicated in the reservoir.
Step 6: Bleed the system
To make sure that there’s no air in the brake system, you will have to bleed the system. This can be done by opening the bleeder valve once more and pumping the brake lever or pedal until there are no air bubbles present in the fluid. You might have to repeat this step multiple times to make sure that all the air has been removed from the system.
Step 7: Tighten the valve
Once the system has been bled successfully, you should tighten the bleeder valve with the help of pliers or a wrench.
Step 8: Check the fluid level
Lastly, you will need to check the fluid level in the reservoir to make sure that it is at the recommended maximum level. Make use of a clean rag or towel for wiping up any spilled brake fluid.
FAQs
What type of brake fluid should I use for my Harley-Davidson?
Harley-Davidson recommends using DOT 3 or DOT 4 brake fluid for its motorcycles. DOT 3 brake fluid is a glycol-based fluid with a minimum wet boiling point of 205°F, while DOT 4 fluid is a glycol-based fluid with a minimum wet boiling point of 230°F. It is important to only use the recommended type of brake fluid to ensure optimal performance and avoid any potential damage.
What are the advantages of using DOT 3 or DOT 4 brake fluid?
DOT 3 and DOT 4 brake fluids offer superior braking performance and are designed to resist boiling and vapor lock. They also provide a higher wet boiling point, which helps to prevent brake fade and offer consistent brake performance.
What should I do if I need to replace the brake fluid in my Harley-Davidson?
If you need to replace the brake fluid in your Harley-Davidson, it is important to first consult the owner’s manual for specific instructions. You will need to drain the old fluid and flush the brake system thoroughly before adding the new fluid. It is also important to follow the manufacturer’s instructions when adding the new fluid and make sure to use the correct type of fluid (DOT 3 or DOT 4).