[ndrifter]

FAQ: DOT3 vs DOT4 vs DOT5 - Brake Fluids Explained

What are the differences and what do they mean? Much perhaps a topic I never come across on Honda forums. I'm going to give you a simple idea on what each category of brake fluids mean and which is the one most suitable/applicable for our CL7/9s for road and track work. After all, selecting the correct and most appropriate brake fluid comes hand in hand with how good your brakes work under all situations and circumstances.

Polyglycol Based DOT3 - Color - Amber | One of the most common finds on the market and have a specific for cars designed for the late 80s period. Although compatible with our CL7/9s should you cannot find the required selected grade, this is not the correct specification to be used from factory recommendation guidelines. DOT3 also absorbs moisture the quickest and has the lowest boiling point and should only strictly be for road use.

Polyglycol Based DOT4 - Color - Amber | The benchmark specifications by the majority of car manufacturers, this is also the specific grade to be used with Hondas/Acura cars regardless of models. DOT4 is designed to absorb moisture slower than DOT3 and has a higher boiling point. This is both suitable for road use and track work. While the OEM Honda DOT4 brake fluid is sufficient for weekend trackdays, meets etc. Using racing specific DOT4 refined brake fluids will increase higher temperature tolerance particularly under hard braking conditions.

Silicone Based DOT5 - Color - Purple | Least common and also the most different from both grades above. DOT5 are primarily designed for cars not equipped with ABS units (Unless otherwise manufacturer specific)and this should not be used unless you're absolutely sure of what you're doing. DOT5 does not absorb moisture and holds the highest boiling point. This brake fluid is not compatible with either categories above and should never be mixed due to it's chemical properties.

Polyglycol Based DOT 5.1 - Color - Amber | Not to be confused with DOT 5, a silicone based fluid. DOT 5.1 is one of several designations of automotive brake fluid, denoting a particular mixture of chemicals imparting specified ranges of boiling point. A brake fluid's dry boiling point is the temperature at which the pure fluid will boil. Wet boiling point concerns the boiling temperature when the fluid contains water. They are DOT 3, DOT 4 and DOT 5. DOT 5.1, like DOT 3 and DOT 4, is a polyethylene glycol-based fluid (contrasted with DOT 5 which is silicone-based). Polyethylene glycol fluids are hygroscopic and will absorb water from the atmosphere, which is necessary to prevent sheer and undiluted water in the braking system, which is very corrosive.

Always take care when handling brake fluid as this will corrode body paint work in a matter of seconds if contact is made. Should accidental spills or drips happen, immediately flush affected surface area with high spraying water and wipe off area.

Should you choose to switch to a higher category or quality/grade brake fluid, it is strongly recommended that you perform a complete brake fluid flush. Never use a mineral or synthetic based oil ala engine oil or transmission fluid in substitute of specific designed brake fluid. Such incompatibility will cause all rubber components in the brake hydraulic system to swell up and leak.

[vr2turbo]

You miss one out. There is a Poly-glycol Based DOT 5.1 that is compatible with Dot 3 & 4.....

[ndrifter]

added bro! tq!

Polyglycol Based DOT 5.1 - Color - Amber | Not to be confused with DOT 5, a silicone based fluid. DOT 5.1 is one of several designations of automotive brake fluid, denoting a particular mixture of chemicals imparting specified ranges of boiling point. A brake fluid's dry boiling point is the temperature at which the pure fluid will boil. Wet boiling point concerns the boiling temperature when the fluid contains water. They are DOT 3, DOT 4 and DOT 5. DOT 5.1, like DOT 3 and DOT 4, is a polyethylene glycol-based fluid (contrasted with DOT 5 which is silicone-based). Polyethylene glycol fluids are hygroscopic and will absorb water from the atmosphere, which is necessary to prevent sheer and undiluted water in the braking system, which is very corrosive.

You miss one out. There is a Poly-glycol Based DOT 5.1 that is compatible with Dot 3 & 4.....

so which DOT u are using?

[vr2turbo]

added bro! tq!




so which DOT u are using?

DOT 4, but this normally comes in yellow colour, not amber.
Slightly more expensive than DOT3, but can withstand much higher temperature (boiling point)

DOT 5.1 less in the market and more expensive. DOT 5 silicone base is not compatible....

[ndrifter]

DOT 4, but this normally comes in yellow colour, not amber.
Slightly more expensive than DOT3, but can withstand much higher temperature (boiling point)

DOT 5.1 less in the market and more expensive. DOT 5 silicone base is not compatible....

will DOT 5.1 better to DOT 4? since u said its alike rite?

sample

[vr2turbo]

will DOT 5.1 better to DOT 4? since u said its alike rite?

sample

Dot 5.1 boiling is even higher, but you don't need. Dot 4 good enough, even your post mention Dot 4 can be used for weekend track day, and you are only using for daily use, so why pay more for Dot 5.1?

Using Dot 3, 4 or 5.1, even mention compatible, best to use by itself, not mixed with each other. Mixing will bring the grade down to the lower.....

[ndrifter]

Dot 5.1 boiling is even higher, but you don't need. Dot 4 good enough, even your post mention Dot 4 can be used for weekend track day, and you are only using for daily use, so why pay more for Dot 5.1?

Using Dot 3, 4 or 5.1, even mention compatible, best to use by itself, not mixed with each other. Mixing will bring the grade down to the lower.....

abt brake fluid any brand that is stand out n best of the lots?

[vr2turbo]

abt brake fluid any brand that is stand out n best of the lots?

Of course for track use ones will be better as can withstand higher boiling temperature but very expensive.
For normal Dot 4 for every day use, a branded one will be good enough. Any petrol/oil company ones, or brands like Bosch etc..

[ndrifter]

Of course for track use ones will be better as can withstand higher boiling temperature but very expensive.
For normal Dot 4 for every day use, a branded one will be good enough. Any petrol/oil company ones, or brands like Bosch etc..

great! thanks manyak2

[vr2turbo]

great! thanks manyak2

No problem.....share share mah.....