It’s time for my two-year brake fluid flush, and because the car is no longer covered by a warranty or maintenance plan, this is the first time I’ll be doing it myself.
It’s an everyday driver. During rush hour, the interstate traffic is frequently stop-and-go. On the track never.
My concern is: For better protection, should I stick with the stock BMW brake fluid or should I swap to another brand? Or would it not be required?
DOT-4 brake fluid is used in every new BMW. Sometimes it is difficult to find, or you can only obtain synthetic DOT-3/DOT-4. I purchased some DOT-4 (“Super 4”) under the Pentosin (German) name at a business that sells vehicle parts for imports. A 1L can and a 1/2L can cost me $16.
Many individuals also utilize the ATE brand, specifically the ATE200 or the ATE super-blue (gold colored).
Thanks. I suppose my biggest concern was whether there was any legitimate justification for me to use something other than OEM brake fluid. especially while I’m driving like I normally do. Would using an aftermarket fluid give me any observable benefits?
In a day-to-day driving scenario, there will be no advantage to ANY DOT 4 over another. I’ve used Valvoline DOT3/DOT4 in numerous BMWs for about ten years. Cheap and simple to find (AutoZone).
If you’re not wasteful, one liter or quart should be sufficient. It wouldn’t hurt to purchase two so you have enough for top-off or the next time.
I also concur with this. Currently, I have Valvoline in both my Z3 and E90. I merely desired a change to something different. Since Pentosin is the original equipment manufacturer’s power steering oil, I assumed that their brake fluid would be adequate for the brake system. It wasn’t too expensive either.
I think Castrol LMA is BMW’s OEM. I was told that many years ago by a parts specialist at Tischer BMW, and I used it for my E30 for a very long period.
Under typical driving circumstances, we advise sticking to the authentic BMW fluid (found HERE).
Flushing is made a little bit easier by switching between blue and yellow on the ATE. Although there is nothing wrong with OEM for daily/street driving, ATE’s price is quite reasonable for a high temperature fluid.
In This Article...
Breathing fluids
BMW brake fluid should be either Normal or Low Viscosity and DOT4, DOT5, or DOT5.1 rated. Low Viscosity fluid is used on any BMW model equipped with Dynamic Stability Control (DSC), which includes nearly all BMWs since 2003, unless the vehicle is being driven on a racetrack. The thicker Normal Viscosity fluid is used for track use and in vehicles without DSC. Although some DOT4 fluids could also be low viscosity, all DOT5.1 fluid is.
The fluid’s dry and wet boiling temperatures are described by the DOT ratings. Wet fluid has absorbed moisture after a year, whereas dry fluid is still fresh out of the bottle. A higher DOT rating is earned by having higher boiling points. However, DOT5.1 is only used for low viscosity glycol-based fluid, while DOT5 is related with silicone-based fluid. Labeled as “DOT4/5” or “Super DOT4”, a Normal Viscosity fluid that satisfies DOT5 boiling points is classified. Although DOT3 fluid can be utilized in a pinch, DOT4/5 is preferable because to its higher boiling points.
Under non-racing conditions, glycol-based fluid (DOT3, DOT4, and DOT5.1) should be flushed/changed every one to two years; however, for track or racing use, this frequency should be substantially higher.
What type of brake fluid is necessary for a BMW 3 Series?
All contemporary cars equipped with ESP and ABS are best suited with pentosin DOT 4 LV brake fluid. All vehicles that need DOT 4 fluid can utilize DOT 4 LV.
Can I replace the fluid in my BMW myself?
The first step in learning how to change brake fluid is to remove the old fluid from the reservoir and replace it with new fluid.
Some automakers advise changing brake fluid every 24,000 miles or every two years. Others fail to mention changing brake fluid at all. However, checking your brake fluid is simple. To check the color, simply dip a test strip into the fluid and match it to the chart on the container.
Although you can’t perform a thorough brake fluid cleanse yourself, you can perform a fluid switch. You won’t completely replace the old fluid with new fluid during this treatment, but you will add enough new fluid to notice a difference.
What is the lifespan of BMW brake fluid?
The standard recommendation is to replace your brake fluid every two years (or 30,000 miles). Moisture can enter the brake fluid even while your BMW is parked in a garage and not being used, which can result in brake failure.
How frequently does a BMW need to change its brake fluid?
Most manufacturers recommend changing your brake fluid every two years, but there are other indications that your brakes require maintenance.
How important is the brand of brake fluid I choose?
The health of the brake fluid is just as important to the proper operation of the braking system as the upkeep of its mechanical and hydraulic components. The braking system depends on the brake fluid’s incompressibility to effectively convert the pressure applied to the brake pedal into hydraulic pressure that the brake caliper can deliver to slow or stop your car.
Additionally, in order to resist boiling when subjected to high temperatures from braking, brake fluid needs to have a high boiling point.
When brake fluid boils, it evaporates into a compressible gas called vapour. If this occurs, the pedal will be compressing gas instead of sending force to the brakes, which will result in a fatally sluggish response time!
Additionally, brake fluid is necessary to protect the braking system’s components from corrosion and to keep it lubricated.
The manufacturer often specifies the suggested intervals for changing brake fluid, though these can change depending on the fluid type.
The braking fluid used by 99% of the cars in the parking lot is glycol-based and very hygroscopic, meaning that it may collect moisture from the air. Brake hoses’ porosity allows brake fluid, which is hygroscopic by nature, to absorb external moisture. This worsens its state and lowers the boiling point. As a result, brake fluid that has been in a car for at least three years has a much lower boiling point than fresh brake fluid from a container that has not been opened. Low boiling points, as previously indicated, cause a diminished response when braking and, in some situations, the Vapour Lock, when squeezing the brake pedal has no impact. When moisture in the brake system is heated substantially, turning to steam, it can cause vapour lock and “compressibility” of the brake fluid. The optimum brake fluid should be transparent and spotless. Brake fluid that is dark and foggy has accumulated contaminants and has to be replenished.
For assistance in selecting the proper DOT-rated fluid for your vehicle, consult the service manual. If you use a DOT rated fluid in a different way than what is advised, your brakes might not work properly.
90% of today’s cars on the road are technically compatible with DOT 3, DOT 4, and DOT 4 Low viscosity brake fluids that are glycol-based in general.
A particular kind of fluid is designed to work with distinct car braking systems. It is essential that the vehicle use that specific type of fluid throughout the remainder of its service life. This is significant since the internal brake system parts have been chosen, tested, and built to work with that specific fluid. DOT 3 and DOT 4 fluids are both glycol-based, but because their chemical make-ups differ, they will affect the system in different ways. It is essential to continue using the precise brake fluid that the manufacturer advises in order to guarantee that the system functions as it should.
What occurs if the wrong braking fluid is used?
Inadequate lubrication, overheating, and possibly transmission failure can result from using the incorrect fluid. Even after flushing the transmission, a mechanic might not be able to undo the damage. Adding brake fluid or motor oil incorrectly might also ruin your transmission.
What is Dot 3 brake fluid?
The polyethylene glycol-based fluid known as DOT 3 braking fluid is intended to tolerate extremely low temperatures without thickening and extremely high temperatures without boiling. DOT 3 brake fluid typically boils at a temperature of 250 degrees Celsius. This product typically looks yellow to amber and smells faintly of glycol. Although this product is only marginally soluble in water, mixing this product with water lowers the fluid’s quality. To be sold in stores, DOT brake fluids must all adhere to a set of industrial requirements.
What makes DOT 5 brake fluid unsuitable?
The chemistry is the key to the solution. Even minute amounts of DOT 5 combined with a glycol-based brake fluid can cause the two incompatible fluids to gel, leading to subpar braking.
Can DOT 4 brake fluid be mixed?
“Both DOT 4 and DOT 5.1 braking fluids, which are glycol-based, are widely utilized in the automobile and cycling industries. The moniker comes from the fact that they are governed by DOT-established rules.
The boiling points of these two brake fluids are the primary distinction. The minimum dry and wet boiling points are one of the requirements that DOT fluid producers must meet. These are the lowest temperatures that the brake fluid can operate at without beginning to boil, which can result in a complete failure of the brakes.
Let’s look at the Department of Transportation’s recommended minimum boiling temperatures for DOT brake fluid.
Remember that these are merely the basic requirements. It is feasible to find DOT 4 brake fluid with a higher boiling point than other DOT 5.1 fluids on the market, and brake fluid producers frequently do so.
Since DOT 4 and 5.1 are both glycol-based brake fluids, they can be mixed without damaging your brake system because they are compatible with one another. Never confuse DOT 5.1 (a glycol-based fluid) with DOT 5, a silicone-based fluid that must never be used with any other DOT fluid.
Which braking fluids can you actually combine without damaging your brake system, then? Let’s examine the graph below.
The silicone-based DOT 5 is the odd one out in this group and is incompatible with all other DOT brake fluids, as can be shown. The worst that can happen when mixing DOT 3, 4 and 5.1 braking fluids, providing it is new fluid, is a decrease in the boiling point of the entire fluid.
Some brake producers, including Hayes and Formula, ship their brakes with DOT 4 brake fluid already added. Some manufacturers, like Hope and Avid, decide to employ DOT 5.1 in their brakes. In order to take advantage of the higher boiling point and enhanced heat resistance of DOT 5.1, many riders with DOT 4 in their brakes will choose to bleed with it.”
What distinguishes DOT 4 brake fluid from DOT 3 brake fluid?
brake fluid DOT 4. The following are the main distinctions between the two: Over time, DOT 3 brake fluid will collect less water from the air than DOT 4, resulting in fewer frequent fluid changes. Due to its higher dry and wet boiling points, DOT 4 brake fluid is more heat-resistant.