Brake Fluid Types Explained ✔️ Difference between DOT 3, DOT 4, and DOT 5.1 Brake Fluid?

Brake Fluid Types Explained ✔️ Difference between DOT 3, DOT 4, and DOT 5.1 Brake Fluid?
brake fluid explained
similar to engine anoint, there are many brake fluid types. Some for casual driver cars, some for the Dodge Hellcat. Knowing what brake fluid to use in your ride is an important separate of vehicle possession ! Come along for the tease as we discuss this critical fluid…

What is the most park brake fluid ?

The answer will have to be DOT 4 or DOT 5.1. however, this will vary wildly according to the make and model of your vehicle. In certain high-performance applications, DOT 5.1 is the norm, although you can find high-performance vehicles and crossovers with DOT 4 brake fluid.

DOT 3 brake fluid is commonly seen in older vehicles, although I noticed my force 1500 likes DOT 3 fluid ! 🙂

What ’ s the difference between DOT 3, DOT 4, and DOT 5.1 brake fluid ?

The biggest dispute between DOT 3, DOT 4, and DOT 5.1 is the boiling point .
suffice it to say DOT 5.1 has the highest wet and dry boiling point among the three, but this doesn ’ t mean it is superior. Some aftermarket brake fluids have the same boil point as DOT 5.1 but are only relegate as DOT 4. Read more about brake fluid differences from Amsoil .

Brake fluid boiling points explained

What ’ s the importance of boiling points ?

scientist looking at beaker
I don ’ thymine mean to sound like a lab rat, but let ’ s talk about the boil orient. Before we begin, we should discuss the role of brake fluid in the brake system .
What’s brake fluid’s purpose?
Modern hydraulic brake systems require brake fluid or hydraulic fluid to transfer the braking wedge from the pedal to the pistons, which are located inside the brake calipers and apply force to the brake pads. This allows you to stop on a dime with extreme preciseness, but this is not constantly the encase .
You see when brake fluid is exposed to higher amounts of moisture ( or when the fluid degrades over clock time ), this besides affects the boiling point of the brake fluid. In effect, moisture lowers the boiling luff of the brake fluid since water ( which is moisture ) has a lower boiling sharpen than brake fluid at 212 F or 100 degrees Celsius .
And when the brake fluid ‘boils’ inside the system, this leads to loss of brake pressure or brake failure altogether. In other words, you wouldn ’ t be able to stop the car safely, or will prevent you from stopping on time to avoid a serious accident .
Maintaining the boiling point or freshness of the brake fluid is also the reason why it is important NOT to use brake fluid from unsealed containers.
Want to know the reason why manufacturers store brake fluid in smaller containers or credit card bottles ? The manufacturer assumes the entire contents will be used immediately after breaking the seal and opening the container. Unlike engine anoint which can last for many years inside the trunk, pouring stored brake fluid in your fomite is like using a lower grade brake fluid ( from DOT 4 to DOT 3, for exemplify ), which besides means lowering the boiling compass point of the fluid in your fomite .

What ’ s the difference between dry and wet boiling decimal point ?

  • Dry boiling point – the specific boiling point without containing water. In other words, it’s the boiling point of fresh brake fluid free from moisture and other contaminants.
  • Wet boiling point – the specific boiling point of the fluid when contaminated with moisture or water, hence the ‘wet’ nomenclature. In other words, wet brake fluid contains water, which explains why the wet boiling point is lower than the dry boiling point.

van braking fast

What are the boiling points of DOT 3, DOT 4, and DOT 5.1 brake fluid ?

here are the boiling points of all brake fluids, including DOT 5. Take note DOT 5 and DOT 5.1 are NOT the same. I ’ ll explain more on this late .

Type of Brake Fluid
Dry Boiling Point
Wet Boiling Point

401 F (205 C)
284 F (140 C)

446 F (230 C)
311 F (155 C)

DOT 5.1
518 F (270 C)
374 F (190 C)

500 F (260 C)
356 F (180 C)

Remember the above figures are the minimal required boiling points prescribed by the Department of Transportation ( DOT ). Some DOT 4 brake fluids may have a higher seethe point than DOT 5.1 and may be classified as SUPER DOT 4, indeed don ’ metric ton be confused. In order to determine the accurate wet/dry boiling point of the bracken fluid, constantly read the label in the packaging .

What are the types of bracken fluid ?

The three main types of brake fluid are :

  • DOT 3
  • DOT 4
  • DOT 5.1
  • DOT 5 (this is an uncommon brake fluid type)

These are all glycol-based fluids. And since the chief differences between the three are the boil compass point, you can assume DOT 3 contains more body of water ( or has a higher water system content ) than DOT 4 and DOT 5.1 .
With that being said, DOT 4 is a neat interpretation of DOT 3, therefore the higher boiling bespeak. DOT 5.1 is a more refine version of DOT 4. This makes it an ideal and cost-efficient upgrade from DOT 4, but only if your fomite truly needs it. If you do a bunch of heavy tow or high-performance/high-load drive applications, flushing out the existing DOT 4 brake fluid and replacing it with DOT 5.1 will yield significant brake improvements, most peculiarly in challenging or coarse drive conditions .
however another type of brake fluid is DOT 5, which is silicone-based. Unlike glycol-based brake fluid which has a tendency to absorb water or moisture due to its hygroscopic properties, DOT 5 brake fluid is the demand opposite. It doesn ’ thymine absorb moisture, so this makes it ideal for repeated high-heat applications such as rush or track applications .
And unlike glycol-based brake fluent, DOT 5 won ’ metric ton injury or burn off paint. This is the chief reason why vintage muscle cars, authoritative cars, and certain motorbike brands like Harley-Davidson recommend DOT 5 brake fluent. This helps to avoid damage to paintwork and plastic panels when servicing or repairing the hydraulic brake system .

Does the type truly count ?

dodge cummins dually
The immediate answer is yes. Yes your brake fluid character matters !

To answer this question foster, you have to know what application you ’ re using your vehicle for. If you ’ rhenium daily driving your 2005 Toyota Corolla to work and back, DOT 3 will be fine. But if you ’ re towing 15,000 pounds in your contrivance 2500 Cummins Dually, you ’ vitamin d benefit from DOT 5.1 .

Can you mix brake fluid types ?

It is constantly better to flush out the old fluent before filling the reservoir with fresh brake fluent, most specially if you ’ re planning to upgrade from DOT 3 to DOT 4 and onwards to DOT 5.1 .
Since DOT 3, DOT 4, and DOT 5.1 are all glycol-based, it is relatively safe to mix the three without damaging or reducing braking performance. But then again, even though it is safe to mix brake fluid types, this is not advisable from a professional distributor point of watch .
however, DOT 5 is silicone-based and should NEVER be mix with glycol-based brake fluid. If you do, it is not unusual to expect spongy brakes, inadequate braking performance, and even damage to caliper seals and hydraulic seals .

In summary, you can mix DOT 3, DOT 4, and DOT 5.1, but it doesn ’ triiodothyronine mean that you should. NEVER mix DOT 5 with a unlike type of fluid !

With you and your kin ’ sulfur guard in heed, it is never a good idea to mess with the brakes in your vehicle. If you know nothing about handling brake fluent or brake servicing, it is better to consult a professional automobile mechanic for alimony and repair .
Brake Fluid Reservoir

How will I know the type of brake fluid in my vehicle ?

There are two main ways to find out : the cover in the master cylinder and the owner’s manual .
Pop open the hood and locate the brake victor cylinder. The cap will tell you the type of brake fluid. besides, check under the hood or around the engine bay near the master cylinder. You may find decals on the type of brake fluid in the fomite .
You can besides check the owner’s manual or the vehicle service manual. It will besides indicate the brake service intervals indeed you ’ ll know the best time to have the brakes checked ( which depends on either time or mileage of the vehicle ) .

How do I flush the previous fluent in my car ?

If you ’ re like me and like videos, EricTheCarGuy did a great television demonstrating this serve. Give it a watch !
Alright, you know what you’re doing huh? Let’s get into the guide to changing your own brake fluid.
You ’ ll need an able assistant and a copulate of handy tools to completely change out old brake fluid in your vehicle. Of course, you can always let a master wield the job, but why spend $ 100 if you can do it yourself ?
Materials needed :

  • Turkey Baster
  • 8mm or 10mm socket or open wrench
  • Small plastic bottle and plastic/rubberized tubing
  • Fresh brake fluid
  • Microfiber towels
  • Jack and jack stands

turkey baster from kohls

  1. Setup your vehicle for the job.
    Park your vehicle in safe and level ground, preferably indoors or inside a garage. Jack up the vehicle, remove the wheels on all four corners and set the vehicle on jack stands. You do still flush the brakes if you don’t have jack stands, but you’ll end up repeatedly raising and lowering the vehicle to complete the job.
  2. Locate the brake fluid reservoir, clean the cap, and suck out the liquid with your turkey baster.
    Pop open the hood and remove the protective cap in the brake master cylinder. What I usually do is to clean the cap first using a diluted solution of water and dish soap to prevent contamination, but you can do so by simply wiping the cap clean using a microfiber towel and move on.After removing the cap, set it aside. Grab the turkey baster and suck out all the old brake fluid inside the reservoir. Make sure to remove as much of the old fluid as you can. Place the discarded fluid in a small plastic jar or container for proper disposal.
  3. Pour in the new fluid!
    Open the new bottle or can of fresh brake fluid. Pour brake fluid inside the reservoir but do not overfill! Replace the cap and tighten lightly. Do not overtighten the cap either since you’ll be pouring fresh brake fluid as you flush out the old.
  4. Find a plastic bottle, you’re going to flush the old fluid.
    Grab a small plastic bottle, preferably one with the cap still on. The idea is to punch a small hole in the cap so you can insert the flexible tubing inside the bottle without removing the cap. Next, fill the bottle with a small amount of fresh brake fluid. The idea is to submerge the end of the tubing to prevent air from entering the system as you flush.
  5. Insert the tube and loosen the bleeder screw.
    Whenever I flush the fluid, I start with the front-left and right-rear side before moving to the right-front and left-rear. The idea here is to start flushing the fluid from the side of the vehicle which is closest to the master cylinder. However, you can flush the brakes in any manner or procedure. I simply prefer to do it the right way.Now we got that out of the way, let’s proceed with the flushing. Insert the end of the tubing into the bleeder screw, which is usually located in the top-rear of the brake caliper. Use an 8mm or 10mm wrench to loosen the bleeder screw. Make sure to insert the tube before loosening the screw to prevent air from entering the system.
  6. Have a friend or assistant sit in the driver seat and pump the brake pedal repeatedly.
    Notice color of the fluid inside the hose as the brake pedal is pumped? As soon as you see clear fluid being pumped out, tighten the bleeding screw and remove the hose. You have successfully flushed out the old fluid from the vehicle!
  7. Refill the reservoir again.
    The next step is to refill the reservoir with fresh brake fluid. The idea here is to flush then refill each time until the job is complete.
  8. Repeat until the brake fluid drains out the same color!
    After refilling the master cylinder with fresh brake fluid, repeat the above-mentioned steps until all the brakes have been flushed individually.

The final step is to install the wheels, lower the fomite back to the prime, and you ’ re done !
As a concluding caution, you should double-check the level of brake fluid and tighten the capital securely before driving off. Don ’ t make it a habit of repeatedly opening or closing the reservoir to check the level of brake fluent. There ’ mho a reason why the reservoir is diaphanous, after all .
Read more about brakes with these guides :


hopefully this guide has helped you better understand all the brake fluid types. If you have any questions or comments, please contact us !

Read more about brake fluid types :
“ Mad Scientist ” Image by André Santana from Pixabay

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Category : Car Brakes