DOT 3 Brake Fluid – Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice

DOT 3 Brake Fluid

DOT 3 Brake Fluid

What is DOT 3 Brake Fluid

DOT 3 brake fluid is a brake fluid that complies with the standards established by the Society of Automotive Engineers (SAE) and the U.S. Department of Transportation (DOT). To comply, the fluid must meet these criteria:

• The fluid must have a stable viscosity and be free flowing at all operating temperatures.

• DOT 3 brake fluid has DRY boiling point of 401°F and a wet boiling point of 284°F.

• Must be non-corrosive to all the metal, rubber and composite materials used in the brake system.

• The anti-corrosion additives must prevent corrosion or rust formation in the system.

• The fluid must have lubricating properties to inhibit wear to seals and other moving parts.

• The fluid must have very low compressibility.

DOT 3 Dry versus wet boiling points

Glycol-based brake fluids are hygroscopic, meaning they have an affinity for water. Even though the brake system is thought to be a “closed” system, moisture can still get in. First, every time a shop or driver opens the master cylinder reservoir, the fluid is exposed to moisture in the air. However, even if you never open the master cylinder, moisture can still get in. As the caliper piston and wheel cylinder pucks move in and out of the bore, pores in the metal can carry moisture into the brake system. Moisture can also penetrate through flexible brake hoses and seals.

Brake materials stop the vehicle by transforming motion into friction and then into heat. That heat can cause the moisture in brake fluid to boil and turn into steam. Since steam is compressible, moisture in the system can greatly reduce braking ability, causing the brake pedal to feel “spongy.”

Studies show that braking performance can drop significantly with just 3% water absorption. In fact, if the fluid contains 3% water, the boiling point drops to 212⁰F.

• The DRY boiling point specification is for fresh, uncontaminated fluid with no water absorption.

• The wet boiling point, is the point at which brake fluid will boil with a specific amount of water absorption. The technical term for this standard is the Equilibrium Reflux Boiling Point (ERBP).

How to measure brake fluid moisure

Use a refractometer or a battery powered tester

Battery powered brake fluid moisture tester

How to test brake fluid condition

Contrary to popular belief, color is NOT a good indication of brake fluid condition. You must check the fluid’s moisture level AND the fluid’s copper content. Metal brake lines are formed from flat steel and rolled into tubing. The seam is brazed. As the anti-corrosion additives wear out, the brazing deteriorates and shows up in the fluid as copper. Test strips are used to measure the copper content. When the copper content exceeds the test values, OR the fluid’s moisture content exceeds 2-3%, the fluid must be flushed to maintain proper braking and prevent further corrosion.

Brake fluid test strips test the state of anti-corrosion additives in the brake fluid by testing for copper content

DOT 3 versus DOT 4 viscosity

DOT 3 has a higher viscosity than DOT 4, meaning the two fluids are NOT interchangeable unless specified by the car maker. Even though DOT 4 has a higher boiling point, which may lead you to think it’s a “better” fluid, it’s lower viscosity may not be right for your particular vehicle.

Always install the recommended brake fluid type.

Posted on by Rick Muscoplat

TPMS System – Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice

TPMS System

What is a TPMS System?

A TPMS System is required on all passenger cars, light trucks and light buses built after September 1, 2007. The tire pressure monitoring system (TPMS) detects tire pressure in one of two ways; direct and indirect.

History of TPMS systems

After a series of fatal sport utility vehicle crashes that resulted in 271 deaths, Congress passed the Transportation Recall Enhancement Accountability Documentation (TREAD) Act of 2000. The deaths were attributed to vehicles being driven with low tire pressure. The legislation required the National Highway Traffic Safety Administration to develop a rule requiring all new vehicles to be equipped a warning system to alert the driver when a tire is significantly under-inflated.

The rule stated that as of Sept. 1, 2007, all new passenger vehicles, trucks and light buses are required to have a sensor-based TPMS system that alerts the driver of a condition where one or more tires is under-inflated by 25% below the car maker’s recommended tire pressure.

Prior to this legislation, some car makers voluntarily installed TPMS systems that were either indirect or direct. So the legislation ended the voluntary compliance are required all car makers to move to direct TPMS

Indirect TPMS

An indirect TPMS system uses the ABS system’s wheel speed sensors to detect an under inflation condition. An under inflated tire has a smaller diameter than a properly inflated tire. Since the ABS braking system compares the rate of rotation of all wheels, it can also detect when a wheel is consistently rotating fewer times per mile than the other tires. In these systems, the ABS system can light the low tire pressure waring light based on revolutions per mile

Direct TPMS

In a direct TPMS system, a tire pressure sensor with the valve

TPMS system sensor

Types of TPMS system sensor mounting: stem mount and band mount

stem is installed on the wheel rim in place of the older style rubber valve stem, or the sensor is installed on a band connected to the center of the rim.

The TPMS sensor reports via radio frequency to a receiver in the vehicle if the tire pressure falls below 25% of the car maker’s recommended tire pressure for that particular vehicle.

What is a TPMS sensor?

Most TPMS sensors are mounted in place of the valve stem and are held in place by a threaded nut. However, other types are held in place in the center of the wheel with a band. The TPMS sensor holds a pressure transducer, radio, battery and electronics. The battery has a projected lifespan of 7-10 years and is not replaceable because the entire unit is sealed in epoxy.

When the battery approaches its end of life, it sends a low battery signal to the receiver. At that point it must be replaced.

TPMS replacement cost

You do NOT have to return to the dealer for a TPMS replacement! Any tire store can fit an aftermarket sensor in your vehicle and program it to your car or truck. Aftermarket TPMS sensors typically cost about 1/3 less than an OEM sensor and they’re almost always made the same vendor. A TPMS sensor replacement from a tire store usually costs around $60 for the part and the labor is often free if it’s installed when you’re getting a new tire or a tire repair.

Posted on by Rick Muscoplat


TPMS System

How Women Can Feel Empowered at the Car Repair Shop

Caring for an automobile can leave some women feeling at the mercy of car repair shops. Maybe you didn’t handle your family’s auto repair issues in the past, so you need some tips on how to safely navigate your way through the maze of shops, parts and terminology.

Nowadays, women are likely to be the main consumers of auto repair services. “Women represent 50 percent of the repair market for automotive service shops, so it’s likely that the individual who takes primary responsibility for vehicle maintenance is female,” said Tony Molla, vice president of the Automotive Service Association, a trade association for automotive service owners and managers.

If you don’t know much about your vehicle but want to avoid getting ripped off at the repair shop, you need to do your homework. “There are plenty of shops out there who take advantage of customers, especially women, because they assume women do not know about cars,” said Andrea Campbell, mechanic and owner of Andrea’s Auto on Martha’s Vineyard, Mass.

To complicate matters, today’s cars are more sophisticated with computerized modules and often inexplicable dashboard lights and codes. And certain repairs may cost more than in the past.

The price of automobile repairs could have significant impact on a budget. According to a recent study from Ally Financial, many Americans could be at risk of a financial emergency from just a $500 car repair, and data provided by the Federal Reserve indicated that 41 percent of American adults could not pay a $400 emergency expense without going into debt.

“Vehicles have changed tremendously over the years and so has the way you service them,” said Jeff Cox, president of the Motorist Assurance Program of the Automotive Maintenance and Repair Association, which establishes service standards for the auto repair industry. “Many of us are familiar with $20 oil changes, but with today’s engine design and the oil required, you might have an oil change that costs over $60.”

Be a Savvy Consumer         

Unfortunately, overcharging and taking advantage of customers unfamiliar with cars often feels rampant in the auto repair world. If you don’t know what to expect, you can be a victim of poor service. Consumer Reports offers suggestions on how to avoid being ripped off by a mechanic.

Be on the lookout, it says, for shops that:

• Suggest or perform unnecessary repairs or maintenance that don’t match the scheduled maintenance recommended in your car’s owner’s manual

• Charge you inflated or excessive fees

• Replace parts that don’t need replacing or use poor-quality parts

Know Your Car

How can you get up-to-speed so you can ask intelligent questions at the repair shop? One way is to educate yourself about cars.

A good start: Read Girls Auto Clinic Glove Box Guide  by Patrice Banks, a mechanic and founder/owner of Girls Auto Clinic in Upper Darby, Pa. who wrote the book to help women learn how cars work and the systems that make a car run.

To empower yourself about your particular car, read your owner’s manual. Then, open the hood and get familiar with what’s there. Teach yourself to check fluid levels:  oil, transmission fluid, power steering fluid and windshield washer fluid.

Ask Car Repair Questions

“An educated consumer cannot be taken advantage of,” advises Molla. “Ask questions. If you don’t understand the answer or if the shop you are dealing with cannot explain everything to your satisfaction, thank them for their time and find another shop that can.”

How can you make sure a shop uses quality parts? “Before approving any work, ask if the parts meet or exceed OEM (Original Equipment Manufacturer) specifications. If there is doubt, ask to see the packaging the part came in,” Cox said. “OEM parts exist because certain companies manufacture auto parts as subcontractors to vehicle manufacturers and use specifications of those manufacturers.”

Molla suggests inquiring about the shop’s warranty policy on parts and service, too. “Again, the key is to ask questions,” he said.

Find a Quality Car Repair Shop

Before you visit a repair shop, watch this Car Care Council video.  And read up on the right questions to ask here.  

Automotive Service Excellence (ASE), which qualifies automotive service technicians, has two good tips for choosing a repair facility: look for a shop before you need one and ask friends for recommendations.

“Look for things like certified technicians, a clean and professional facility, friendly service consultants who are able to explain what is being done to your vehicle and why you need that service and membership in professional organizations like the Automotive Service Association,” Molla said.

Cox suggests finding a repair facility that participates in the Motorist Assurance Program. “The Automotive Maintenance and Repair Association’s Motorist Assurance Program creates standards for the automotive repair industry,” he explained. “Ask your service provider if they participate in the program or look for a decal on the front door.”

A reputable auto service provider won’t try to take advantage of customers and can make a living on dealing honestly with the public. “I’m sure I don’t make as much money as I could by taking people for a ride, but that is one ride they don’t need to take, in my opinion,” said Campbell.

By Debbie L. Miller

Debbie L. Miller has been a freelance writer, playwright and actor for more than 25 years. She writes in Brooklyn, N.Y., and won the 2017 Mona Schreiber Prize for Humorous Fiction and Nonfiction.

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