Brake Fluid: What It Does, Types, Changing, Costs, FAQs
Think of your brake organization as a be organism .
If the master cylinder is the “ kernel, ” then brake fluid is the “ blood ” pumping through the brake lines. Without that brake fluent, your brakes won’t workplace .
therefore, what precisely is brake fluid, and why is it so crucial ?
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In this article, we ’ ll prima donna into everything about brake fluid, including how it works, problems associated with it, and the easiest way to remedy brake fluid problems .
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What’s Brake Fluid And What Does It Do?
Brake fluid is a hydraulic fluid used in mod hydraulic brake systems .
Most brake fluids you ’ ll brush are glycol-based, but there are silicone-based and mineral oil-based fluids besides .
thus how does brake fluid work ?
When you depress the brake pedal, brake fluent transfers that force to your magnetic disk brakes ( or your drum bracken ) to stop the wheels from spinning .
hera ’ s a detail summation of what happens :
- The force from your foot pressing down on the brake pedal is amplified by a vacuum booster.
- The vacuum booster activates the master cylinder, which converts that force into hydraulic pressure by pressurizing the brake fluid in the brake line.
- That hydraulic pressure is transmitted through the brake fluid, engaging the braking mechanism — which could be a brake caliper (in disc brakes) or a wheel cylinder (in a drum brake).
- The brake caliper clamps a brake pad on each side of the brake rotor (or the wheel cylinder pushes brake shoes on a brake drum), stopping the wheel.
now that you know how it works, let ’ s look at the key characteristics of brake fluent .
4 Brake Fluid Characteristics You Should Know
There are certain brake fluid characteristics that you need to know to understand it better :
1. It Has A High Boiling Point
Brake fluid is exposed to very high temperatures, so it naturally has to have a high boiling point to withstand this .
Brake fluid has types two boiling points :
- The dry boiling point is the boiling of fresh brake fluid.
- The wet boiling point is its boiling point after absorbing some moisture.
The dry boiling point is always higher as it represents the boiling decimal point of new brake fluid. The wet boiling point is what it ’ mho expected to be after some moisture contamination in actual conditions .
If the temperature increases beyond its seethe point, the brake fluid will vaporize into accelerator, reducing its ability to transmit hydraulic blackmail and reducing braking capacitance .
The older your car ’ s brake fluid is, the lower its boil luff is likely to be ( because of moisture exposure ), and the faster it will vaporize in extreme temperatures .
2. Maintains Constant Viscosity
Viscosity indicates how thick a liquid is and its ease of run .
Brake fluid needs to maintain changeless viscosity over a wide temperature roll as it needs to perform the same way in different temperature conditions .
This is particularly crucial in anti-lock braking systems ( ABS ) or grip and stability see systems, as these systems use microvalves and need rapid activation .
3. It Is Corrosive
Pure brake fluid is corrosive, which is why commercial brake fluid normally has corrosion inhibitors added to it. This prevents corrosion in brake parts like the caliper or maestro cylinder as moisture enters the brake system .
The additive package depends on the manufacturer and may not only include corrosion inhibitors but have anti-wear and anti-foaming qualities besides .
Note : silicone fluid is less corrosive to paintwork, unlike a glycol-based fluid .
4. Has Low Compressibility
compressibility refers to how something ( like liquid ) reduces in size under coerce .
Brake fluid has to maintain a abject tied of compressibility ( unlike a sponge, which is highly compressible ). Otherwise, your bracken bicycle feel might keep change, and the hydraulic pressure generated won ’ deoxythymidine monophosphate be applied systematically on the bracken rotor .
following, what are the different types of braking fluids out there ?
5 Types Of Brake Fluid
When it comes to types of brake fluid, you ’ ll probably notice different “ DOT ” labeled fluids .
These are defined by the Federal Motor Vehicle Safety Standards ( FMVSS ), where “ DOT ” stands for the US Department of Transportation. There are besides international standards defined under ISO 4925 and grades determined by the SAE ( Society of Automotive Engineers ) .
however, the DOT brake fluid documentation is widely used in many countries, so we ’ ll stick to that .
1. DOT 3
The DOT 3 fluid is an low-cost glycol-based fluid that ’ s the most common type of brake fluid used nowadays .
Fresh DOT 3 fluid is an amber coloring material and has a dry boiling sharpen of 401oF. But when fully degraded, the boiling point drops to 284oF .
Glycol fluid is highly corrosive and will remove key .
2. DOT 4
DOT 4 brake fluid is glycol-based fluid like DOT 3, but with additives to increase its minimum boil point .
There are different types of DOT 4 brake fluid, like DOT 4 Plus or DOT 4 Racing .
All DOT 4 fluids have a higher boiling point than DOT 3 fluid, starting at 446oF .
DOT 4 bracken fluid is normally amber like DOT 3, except for DOT 4 Racing, which has a blue additive. While DOT 4 fluent can handle higher temperatures, it besides needs to be changed more frequently .
3. DOT 5
DOT 5 fluid is entirely different from DOT 3 and DOT 4 as it ’ s a silicone fluid .
Because it ’ randomness silicone-based, it doesn ’ thymine attract water, prevents rust, and doesn ’ deoxythymidine monophosphate corrode paint. It has a eminent dry boiling point of 500oF and is typically purple to differentiate it from DOT3 and DOT4 .
however, it ’ second about 4x more costly than DOT 3 and is outperformed by some peculiarity DOT 4 fluids. It can besides become foaming with air bubbles that can be harder to bleed out, which is why it ’ s not recommended for vehicles with an ABS .
4. DOT 5.1
DOT 5 and DOT 5.1 phone very exchangeable, but they ’ re actually very different brake fluids .
DOT 5.1 brake fluid is glycol-based, like DOT 3 and DOT 4, but has a alike boiling point to DOT 5 fluent. It ’ second besides around 14x more expensive than DOT 3 !
You ’ ll likely find DOT 5.1 bracken fluid used for high-performance vehicles, subspecies cars and besides in heavy-duty applications because of its high boil point .
5. Mineral Oils (LHM)
In 1966, Citroen introduced the LHM ( Liquide Hydraulique Minéral ) — a mineral oil used in specific Citroen engines and braking systems. Some Rolls-Royce and Maserati models use it excessively .
LHM handles temperatures better than DOT 3 and DOT 4, with a dry boiling charge of 480°F. There ’ s besides no corrosion because it ’ s a mineral petroleum .
nowadays that you know the unlike types of brake fluid, let ’ s go over some of the potential problems you could encounter :
4 Brake Fluid-Related Problems
here are some brake fluid-related problems you might face :
1. Fluid Leaks
A brake fluid leak is a mechanical trouble, so it can occur with any type of brake fluid .
When there ’ s a leak, hydraulic pressure in the brake line drops, and air bubbles may enter the brake organization — affecting bracken performance and possibly leading to brake failure .
A leak can happen anywhere, from tear bracken hoses to a fail master cylinder. If your brake pedal point sinks to the fomite floor, that ’ s a impregnable indication that you ’ rhenium losing brake fluid .
2. Moisture Creeping In
Brake fluid is generally hygroscopic, meaning it steep moisture. Water contaminant degrades brake fluid over time, decreasing its boil indicate and brake performance .
Though the brake organization is a close system, moisture can even seep through microscopic holes in arctic brake hoses or via progressive seals. It even happens when the brake fluid reservoir is left overt excessively long .
tied though brake fluid has corrosion inhibitors, those additives will break down over time .
When this happens, moisture in the brake fluid may cause rust, blocking humble passages in the brake hardware. Rust can create failure in the vehicle ’ south brakes — like a adhere caliper, for exemplify .
4. Fluid Contamination
not alone does brake fluid go regretful over time with moisture vulnerability, but components in the brake system will deteriorate besides. Pieces of condom from a wheel cylinder or bits of debris can besides end up in the brake fluent, making it sludgy and reducing brake fluid performance .
now that you know what brake fluid is and what can go wrong with it, we ’ rhenium sure you have a few questions .
Let ’ s go over some of them :
8 Brake Fluid FAQs
here are the answers to some FAQs you might have about your vehicle ’ s brake fluid .
1. When Is A Brake Fluid Change Needed?
For regular daily drive, it ’ s a thoroughly principle of finger to change your brake fluid at least once in two years. however, constantly follow the manufacturer ’ second recommendations if there is one. You will find their recommendations in your vehicle ’ south owner ’ s manual .
once the right come of time has elapsed, you can always ask your mechanic to change your brake fluid when you get an locomotive anoint exchange. equitable keep in beware that the hard you are on your vehicle ’ south brakes, the fast you ’ ll need a change .
2. What’s The Benefit Of Changing Brake Fluid?
apart from ensuring that your brakes are in perfective condition, you may want to consider the price benefits attributed to consistent brake fluid care .
While flushing and replacing your car ’ s bracken fluid may cost around $ 100 for most vehicles, replacing rusted brake calipers or brake lines ( which originate due to brake fluid problems ) can be much more expensive .
3. What Are The Signs Of Low Brake Fluid?
Some tell-tale signs of low bracken fluid are :
- Your brake pedal feels soft or spongy.
- There’s a brake fluid leak under the car.
- The ABS warning light glows.
- You have worn vehicle brake pads.
4. Can I Check The Brake Fluid Condition Myself?
Yes, you can .
But should you ?
That depends .
You can open the bracken fluent reservoir to take a quick count at the vehicle ’ s brake fluent .
Old fluid darkens with age and contamination. You can besides check the brake fluid level to see if it has dropped below the minimum line .
But remember — brake fluid is toxic .
besides, never leave the brake fluid reservoir loose longer than needed because you ’ ra exposing it to air. That ’ s why it ’ mho always better to get a machinist to inspect it .
tied if your brake fluid hasn ’ thymine turned sludgy or the fluid charge is fine, only a professional can test it for moisture contamination and tell you if a switch is required .
5. Can I Change Brake Fluid Myself?
It ’ s not recommended .
Unless you ’ re an experienced mechanic, please ask a professional to change the old fluid for you .
6. Can Different Brake Fluids Mix?
broadly no .
Use whatever is recommended for your vehicle .
however, if you ’ re in an hand brake where you need to top off your brake fluid because of a leak and your regular DOT fluid international relations and security network ’ thymine available, there are some options .
Glycol-based fluids like DOT 3, DOT 4, and DOT 5.1 are technically compatible with each other. however, it ’ s always better to get refilled with the same brake fluent .
Note : If you ’ re using DOT 5 or LHM, don ’ metric ton try mixing them with anything else as they ’ re not compatible .
7. What Is A Brake Fluid Flush?
A brake fluid affluent is when all the brake fluent is removed from the brake system using a vacuum and replaced with clean fluent .
8. What Is Brake Bleeding?
Brake bleed is where just enough newly brake fluent is pushed through the brake lines to remove air bubbles. This brake fluid service is slightly unlike from a brake blush as it ’ mho quick and cheaper, albeit less comprehensive .
A brake fluid flower or bleed can cost anywhere between $ 70- $ 120, but it can cost more, depending on your car ’ mho gain and mannequin .
Your following question may be :
What ’ s the easiest way to deal with a brake fluid change or issue ?
The Most Convenient Fix To All Your Brake Fluid Issues
Because of the vital function it plays in your brake system, you ’ ll want your brake fluid adequately serviced .
That ’ randomness why it ’ mho important to find a authentic machinist for your brake repairs .
Make sure that they :
- Are ASE-certified
- Use only high-quality replacement parts and tools
- Offer a service warranty
fortunately for you, RepairSmith is not only easy to contact but besides checks all those boxes !
RepairSmith is a convenient mobile fomite repair and maintenance solution, and here ’ s why they ’ re your # 1 option :
- Your brake fluid servicing and brake repairs can be done right in your driveway
- Online booking is convenient and easy
- Competitive, upfront pricing
- Professional, ASE-certified technicians perform the vehicle servicing
- All repairs and maintenance are performed with high-quality equipment and replacement parts
- RepairSmith provides a 12-month | 12,000-mile warranty for all repairs
For an accurate estimate of rectify costs, barely fill this on-line form.
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Don’t Overlook Your Brake Fluid Needs
Brake fluid is an incredibly crucial component in your brake system, so don ’ deoxythymidine monophosphate overlook it .
If you ’ re concerned about the fuss of finding a automobile mechanic or driving to a repair shop to get your brake fluid checked, you don ’ t need to worry .
Book an date with RepairSmith, and an ASE-certified brake technician will be at your driveway, ready to address your brake fluid needs ASAP .