AMSOIL DOMINATOR® DOT 4 100% Synthetic Racing Brake Fluid
Brake fluid acts as a hydraulic fluid, transferring power and lubricating brake system components while also preventing corrosion. It must contend with extreme heat and the inevitable moisture contamination that can lead to a brake system failure. AMSOIL synthetic brake fluids surpass Department of Transportation (DOT requirements and provide auto enthusiasts and racers with a brake fluid that delivers superior high-temperature performance.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL DOMINATOR® DOT 4 100% Synthetic Racing Brake Fluid.
AMSOIL DOMINATOR DOT 4 100% Synthetic Racing Brake Fluid
AMSOIL DOMINATOR DOT 4 Synthetic Racing Brake Fluid is a 100 percent synthetic glycol-ether fluid engineered for road-race, autocross, time-attack, drag-race, off-road race, and serious track-day brake systems. It meets DOT 4 chemistry with a dry equilibrium reflux boiling point of 580 degrees F (304 degrees C) and a wet ERBP of 410 degrees F (210 degrees C), well above DOT 4 minimums of 446 degrees F dry and 311 degrees F wet.
Race-grade dry and wet boiling points
Repeated heavy braking forces fluid temperature toward the caliper limit. When boiling-point margin runs out, vapor forms in the lines and pedal travel grows long. DOMINATOR DOT 4 Racing Brake Fluid carries a 580 degrees F dry ERBP and a 410 degrees F wet ERBP, exceeding DOT 4 dry minimum by 134 degrees F and DOT 4 wet minimum by 99 degrees F, giving the brake system thermal headroom against vapor lock during repeated stops from speed.
Wet ERBP reflects fluid that has absorbed 3.7 percent water, the level used by FMVSS test procedure to simulate aged service fluid. Wet boiling-point margin is the number that matters most after seasonal storage and humid race weekends, because brake fluid is hygroscopic and absorbs moisture through reservoir cap vents, hose walls, and seal interfaces.
Firm pedal feel under sustained load
The unique chemistry behind this fluid increases boiling points well beyond DOT standards even when contaminated with 3.7 percent water, and it maintains a stable viscosity over a wide temperature range. The fluid flows easily at the high pressures generated in modern automotive and competition brake systems to deliver solid, reliable braking response. A nitrogen blanket is added to each bottle during manufacturing to purge moisture and protect dry boil performance until the cap is opened.
Controlled cold-temperature viscosity
Cold race mornings and pre-grid warm-up laps depend on consistent pedal feel before the system reaches operating temperature. DOMINATOR DOT 4 Racing Brake Fluid measures 1550.0 cSt at -40 degrees C and 2.0 cSt at 100 degrees C, both inside the FMVSS DOT 4 viscosity envelope of 1800.0 cSt maximum cold and 1.5 cSt minimum hot. ABS, traction-control, and stability-control circuits modulate hydraulic pressure thousands of times per stop, and a fluid that stays within DOT viscosity limits across that range supports predictable electronic intervention.
Water-contamination defense for off-season storage
Water seeps into the brake system through microscopic pores in flexible brake lines, around seals, and through the reservoir fill cap. Once present, it reduces boiling points and corrodes brake parts, lines, and seals. The high wet ERBP of this racing fluid counteracts that drift, and nitrogen-purged packaging protects dry boil during shelf life. Annual fluid changes between race seasons restore boiling-point margin to the as-poured value.
Compatibility with DOT 3 and DOT 4 systems
DOMINATOR DOT 4 Racing Brake Fluid is a glycol-ether fluid built around the DOT 4 chemistry family. The 580 degrees F dry and 410 degrees F wet ERBP figures also clear the DOT 3 minimums of 401 degrees F dry and 284 degrees F wet, so the racing fluid is suitable for systems originally filled with a DOT 3 or DOT 4 service fluid that need a higher thermal margin for competition use. This product is not interchangeable with DOT 5 silicone brake fluid; silicone-based DOT 5 is a separate chemistry and the two should not be mixed in the same hydraulic system.
Recommended applications and service intervals
Use AMSOIL DOMINATOR DOT 4 Synthetic Racing Brake Fluid in racing applications that require a DOT 4 product. Change fluid once a year for maximum performance. The combination of a 580 degrees F dry ERBP and a 410 degrees F wet ERBP suits the heat loads encountered in road-race, autocross, time-attack, drag-race, off-road race, and high-volume track-day duty cycles where stock-spec fluid pushes into vapor lock.
Race service: change brake fluid once a year for maximum performance, with a fresh bleed of every caliper before any major race weekend or HPDE event.
Use in systems calling for a DOT 4 service fluid; the racing-grade boiling points also clear DOT 3 minimums for systems that originally specified DOT 3.
Do not mix with DOT 5 silicone brake fluid. The two chemistries are not compatible in a shared hydraulic system.
Match fluid selection to the owner manual classification for any street-driven vehicle. The vehicle-specific service interval is determined by the manufacturer; consult the AMSOIL vehicle lookup guide or the original owner manual for the correct DOT classification.
This product is not available in Canada. Recycle used fluid and the empty bottle through an approved automotive recycling program. Verify the master cylinder cap or owner manual specification before topping off a street-driven vehicle.
Typical technical properties
Property
Value
Equilibrium reflux boiling point, dry
304 degrees C (580 degrees F)
Equilibrium reflux boiling point, wet (3.7 percent water)
210 degrees C (410 degrees F)
Kinematic viscosity at -40 degrees C (-40 degrees F)
1550.0 cSt
Kinematic viscosity at 100 degrees C (212 degrees F)
Order AMSOIL DOMINATOR DOT 4 Synthetic Racing Brake Fluid
AMSOIL DOMINATOR DOT 4 Synthetic Racing Brake Fluid ships in a nitrogen-purged 12 oz. bottle as product code BFRCN-EA, and a case of twelve 12 oz. bottles ships as BFRCN-CA for race teams and shops that bleed multiple cars per weekend. AMSOIL products are backed by the AMSOIL Limited Warranty. Match the right product to any street-driven vehicle through the AMSOIL vehicle lookup guide and review the broader passenger-car lineup in the AMSOIL car oil guide, then place the order through the order page for AMSOIL DOMINATOR DOT 4 Synthetic Racing Brake Fluid.
I flushed the brakes on my 23' Road Glide with the Amsoil Dot 4 Brake Fluid and it appeared to be of a very high quality. Very responsive company that backs and supports their products. that is why I have this brand as all the fluids in my bike . Its hard to provide much more comment since this is the first change of the brake fluid. I will provide more comment at next change.
What is the boiling point of AMSOIL DOMINATOR DOT 4 Racing Brake Fluid?
DOMINATOR DOT 4 Racing Brake Fluid has a dry equilibrium reflux boiling point of 580 degrees F (304 degrees C) and a wet ERBP of 410 degrees F (210 degrees C) measured at 3.7 percent water contamination. Both figures exceed FMVSS No. 116 DOT 4 minimums of 446 degrees F dry and 311 degrees F wet.
How often should racing brake fluid be changed?
Change fluid once a year for maximum performance in race service. Race teams running long, high-load events should also bleed every caliper before each event so the fluid in the corners (where temperatures peak) starts the weekend at the as-poured boiling point.
Is DOMINATOR DOT 4 Racing Brake Fluid compatible with DOT 3 systems?
Yes. DOMINATOR DOT 4 is a glycol-ether DOT 4 fluid, and its 580 degrees F dry and 410 degrees F wet boiling points also clear the DOT 3 minimums of 401 degrees F dry and 284 degrees F wet. Systems originally filled with a DOT 3 service fluid that need a higher thermal margin for competition use are a fit.
Can DOMINATOR DOT 4 be mixed with DOT 5 silicone brake fluid?
No. DOT 5 is a silicone-based fluid and is a separate chemistry from DOT 3, DOT 4, and DOT 5.1 glycol-ether fluids. DOMINATOR DOT 4 should not be mixed with DOT 5 silicone fluid in the same hydraulic system.
Will this racing fluid work on a street-driven car?
It can be installed in passenger-car and light-truck systems that specify a DOT 4 service fluid, and the once-per-year racing service interval applies. For a daily-driver fluid built for two-year intervals across DOT 3, DOT 4, and DOT 5.1 applications, AMSOIL DOT 3 and DOT 4 100 percent Synthetic Brake Fluid is the broader-coverage option.
Why does brake fluid absorb water?
Glycol-ether brake fluid is hygroscopic and attracts moisture through pores in flexible brake lines, around seals, and through the reservoir fill cap. Absorbed water lowers the boiling point and corrodes calipers, lines, and seals. A racing fluid with a 410 degrees F wet ERBP keeps useful boiling-point margin even after seasonal moisture absorption.
What package sizes are available?
Two package configurations ship from AMSOIL: a single 12 oz. bottle as product code BFRCN-EA, and a case of twelve 12 oz. bottles as BFRCN-CA. Each bottle is sealed with a nitrogen blanket during manufacturing to purge moisture and protect the dry boiling point until the cap is opened.
