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May 2007 E-mail Newsletter
“Q & A Time”
Brake Fluid and Low Pedal Problems:
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Recently I have noticed that my car has become increasingly harder to stop and the brake pedal seems to travel down a lot farther than it used to, what could be wrong?
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| A. |
The problem could range from a simple adjustment or air in the system problem to the most severe; early warning symptom of total failure. Having a professional perform the necessary bleed, adjust and inspection to determine exactly the nature of the problem would be advised. Because of anti-lock brakes and the ever increasingly complex braking systems it is not a good idea to allow a “shade tree” mechanic or yourself to risk damage to extremely expensive components. It is better to allow a certified technician to perform the task.
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| Q. |
After recently having my brakes repaired, the service adviser informed me that I need to set my parking brake every time I park my car. He said it assisted in keeping the rear brakes adjusted, is this true, and how?
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| A. |
Your service adviser is absolutely correct and better educated then most. Most modern cars and light trucks use what is called a single or non-servo rear brake. These brake designs have the self adjuster connected to the parking brake assemblies and do require park brake usage to ensure rear brake adjustment. This not only ensures proper rear brake operation but also helps keep the brake pedal high and the brakes functioning better keeping excess load from prematurely wearing the front brakes. The days of having to sharply applying the brakes while moving in reverse are almost gone, some vehicles still require this, so check with your brake system specialist to find out what kind you have.
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| Q. |
While changing my oil, I checked my brake fluid, it was a little low so I added some and noticed that the new fluid looked very clear compared to the old fluid. Is the fluid going bad or is that normal?
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| A. |
Both. Brake fluid is the most overlooked component in the braking system of vehicles and it is one of the most important components in that system. Brake fluid is formulated to tolerate moisture absorption, control rubber expansion and corrosion, and acts as a lubricant. It also must not boil or freeze in brake systems over a wide range of operating temperatures. The level is checked occasionally, but very seldom is brake fluid completely replaced unless the vehicle’s braking system undergoes a major overhaul.
Most technicians know that brake fluid deteriorates with age due to moisture and contamination. DOT 3 and DOT 4 brake fluids are polyglycol based. This glycol ether blend of fluids is “hygroscopic” which means it attracts and absorbs moisture. This process takes place every time you leave the cap off the container or check the fluid in the master cylinder reservoir. Moisture is even absorbed through microscopic pores in rubber seals and hoses in the brake system. Also, keep in mind, when you use your brakes, heat is generated at the friction contact points. As your vehicle sits, your brakes cool down. Therefore, over a period of time, the heating and cooling action of your brake system will condense moisture in the closed hydraulics system. DOT 3 and DOT 4 brake fluid will absorb that water and keep it from effecting hydraulic components and helps prevent or at least slow down, the corrosive action. Even though brake fluid absorbs moisture, it cannot continue to absorb it indefinitely, which is why it is recommended that you flush the system and refill with fresh brake fluid every two years.
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