Brake Component Repairs

 

Brakes

Hendersonville Muffler and Brakes repairs brake systems every day. We have excellent pricing with "brake specials" on disc brakes with a lifetime warranty on the ceramic disc brake pads and a two year warranty on the rotors. My favorite quote from our customers is, "I am not a mechanic but I do my own brakes". You put your family in your car or truck! Brakes aren't optional equipment in vehicles, they are a necessity. You can push a car that doesn't run, but you cannot stop a 3,000 pound car if it has no brakes. over 80% of the disc brakes that come into our shop which have been repaired already are not assembled correctly. This percentage goes up even higher for drum brakes. we find almost 90% of the drum brakes that have been previously repaired are not assembled or lubricated correctly.

We see a lot of shops that don't think that the parking brake/ emergency brake is important to the vehicle. We live in Hendersonville, Tennessee! The parking pawl in an automatic transmission has a pin the size of a pencil holding it in place. If your car or truck is parked on a hill without the parking brake applied you have several thousand pounds being supported by a pin the size of a pencil! Picture yourself or your loved ones being run over by your car or truck and suddenly having the parking brake in working condition makes perfect sense. it is really hard to find a level spot here in Hendersonville. Almost every inch of Middle Tennessee is a hill or valley.

Many shops here in Middle Tennessee don't flush the brake fluid or use power bleeders when they install new brake master cylinders and even fewer have the knowledge or training to repair anti-lock braking systems. We are able to find the mysterious problems in braking systems cause by brake proportioning valves or other brake components because we have technicians trained to repair the ENTIRE braking system.

Hendersonville Muffler and Brakes has the latest equipment and certified trained technicians to make sure that your braking system is repaired correctly. We have diagnostic equipment, Alldata and Identifix information systems. We have factory and after-market scan tools and diagnostic equipment to properly diagnose and repair your full braking system including the parking brake. (We also repair the electronic parking brakes found in many late model cars and trucks) We repair anti-lock braking systems required by law after 2007 and the old fashioned conventional braking systems found on older cars and trucks. We "bleed" our brakes with the proper power bleeders that the brake manufacturers recommend. We lubricate everything in the braking system to make sure that your brakes will release when you release the pedal which allows the brakes to cool down when you are not using them and greatly extends the brake life. (Most front brakes last about 60-80,000 miles if they are properly installed and lubricated. Most rear brakes last about 90-120,000 miles if they are properly installed and lubricated).

We basically just repair the braking system correctly as the original manufacturer designed them so that you will stop with confidence for thousands of miles. Don't let untrained mechanics repair your brakes. Bring your vehicle to Hendersonville Muffler and Brakes and have your brakes repaired by trained professionals and most customers find that we also have the most reasonable prices for brake repairs in Hendersonville, Tennessee as well!

Brake Component Repairs

The technicians at Hendersonville Muffler and Brakes repair many different systems on cars and trucks every day. Take for example brakes and the individual components that make up the braking system. Everyone wants their braking systems working correctly but most technicians only look at the brake pads and brake shoes when performing a safety check on the vehicle. The braking system is just that. A system of components that work together to stop the car or truck. I wrote this page to explain a little about each component of the automotive braking system as the whole system must work together to reliably stop your car or truck.

What Is Brake Fluid And The Brake Fluid Reservoir?

Brake Fluid

The original cars used cable operated braking systems. They used only mechanical force to actuate the brake shoes. If you got the car up to any speed at all you could not get the car, or even worse, a truck to lock the tires up and stop the vehicle quickly. Many people were run over because of the lack of braking effort provided by cable operated brakes.

Then hydraulic brakes were invented. By using hydraulic pressure against the brake shoes you could apply thousands of pounds of pressure to the brake shoes while only applying a small amount of pressure with your foot. By it's name and definition hydraulic means liquid. The original hydraulic systems used water to operate. Believe it or not water does an excellent job in hydraulic systems. Many hydraulic systems in use today still use water to produce hydraulic pressure. The main problem with using water for braking systems was that the water would boil out of the brake reservoir too quickly. A second problem was that water caused corrosion in the system. Yet a third problem is that water does not offer very many lubricating properties. Automotive Engineers needed a fluid that would supply all of these needs so a fluid was invented that would serve all of these functions at once and it was named simply brake fluid.

Brake fluid has undergone a few changes over the years but the original principal requirements are still there. The fluid must withstand high temperatures without boiling out of the brake fluid reservoir. Brake fluid must keep the internal components of the braking system lubricated and allow the components to slide against one another without damaging each other. Brake fluid also has corrosion inhibitors which do a good job of keeping the internal components of the braking system from deteriorating from corrosion. Hydraulic fluid is used in many other applications but it's slippery oil based formula was dangerous in braking system applications. (Brake fluid is not petroleum based and mixes or rinses completely with water). When you consider all of the advantages that brake fluid brought to the auto industry it is amazing it does not cost more.

Brake fluid is and always has been stored in an area called the brake fluid reservoir. A reservoir is just a French word for a liquid bearing container. The original brake fluid reservoirs were just a hollow area in the top of the master cylinder. This worked pretty well and this method is still used by many manufacturers today. However most car and truck manufacturers today use a plastic see through brake fluid reservoir so that the owner of the car can check the brake fluid without getting dirty. This also allows technicians to see when the fluid becomes contaminated. (If you look into the brake fluid reservoir and the fluid is any color other than what it originally was, (clear) then it is time to flush the system and replace the brake fluid) Most brake fluid is clear but a few synthetic fluids are red or purple. Any time you look at your brake fluid and it is black you need to have the brake fluid flushed out. Black fluid is normally contaminated with algae. Because brake fluid mixes with water moisture from the air mixes into the system and carries with it algae and the acids that algae produce. The brake fluid is probably the single most important part of the modern braking system.

The Brake Master Cylinder Is The Master Of The Braking System

The brake master cylinder sits on the front side of the engine fire wall directly in the back of the brake pedal in most cars. Your foot applies pressure to the brake pedal and this pressure is applied to the brake master cylinder. It is the beginning of all of the braking action in your car or truck. At Hendersonville Muffler and Brakes we have replaced thousands of brake master cylinders since we moved here. We have also had a lot of customers come to our shop telling us that the master cylinder was bad when the real problem was brake adjusters not working, anti-lock brake system components, or other brake components that were either not working, not properly lubricated, out of adjustment, or broken or bad brake lines. The brakes in your car are by far the most important system in the vehicle. We completely understand hydraulic theory and the physical operation of the braking system.

The master cylinder is basically a block of metal, (usually aluminum but some old ones were made of steel), with a bunch of holes drilled in it. When you apply your foot to the brake pedal the pedal assembly pushes a rod in the center of the brake master cylinder called the piston assembly. The piston assembly has rubber seals in it so that it fits tight enough to force the fluid to travel the same direction the piston does. This means you put your foot down and the fluid travels forward in the cylinder and forces the wheel cylinders or the caliper pistons out. When you let your foot off of the brake pedal the brake master cylinder piston travels backwards and relieves the pressure from the wheel cylinders and caliper pistons. The system is very basic and the good news is you don't have to understand how the system works. We understand it very well and we will diagnose and repair any braking system problems quickly and for a reasonable price.

I have watched mechanics bleed a braking system for 3 days trying to figure out why the system was not working correctly. (If your mechanic shop is not using a power bleeder like the manufacturer recommends then they are shortening the life of your master cylinder anyway). If you can't figure out what is wrong with ANY braking system in less than 1/2 hour you need to go back to school, (or go to school for mechanics for the first time). We have trained technicians working in our shop who can tell you reliably what is wrong with your braking system in just a few minutes. We live in a small town here in Hendersonville, Tennessee. It is a small town but it is too big to walk around so our clients need their cars to be fixed quickly and correctly. We have developed a great reputation for repairing cars and trucks here in Middle Tennessee by providing excellent automotive repair services for fair prices. Come in and see why our customers have been so satisfied.

 

Drum Brakes

     Here you see a typical drum brake system. I say typical but the truth is that there are literally thousands of different designs for drum brake systems. Drum brake systems are the first brake systems used on cars and trucks. They actually used drum brakes first on carriages. The first drum brakes actually used cables to operate and they were VERY difficult to stop. Drum brake systems started using hydraulic wheel cylinders to make the systems MUCH more powerful and to allow people who didn't have legs that look like tree trunks to stop the car or truck.

Disc Brakes

    During World War II the United States Military needed to be able to land planes in smaller fields so a new type of braking system was invented to give more powerful braking. A metal plate or, "disc" was used with two flat brake shoes, (renamed brake pads) that were designed to squeeze the disc from both sides and stop the airplane quicker. It didn't take long before disc brakes made their way into cars. With hydraulic braking and the use of front disc brakes cars became much easier to stop. Because disc brakes were originally made to stop vehicles from high speeds they had a tendency to be rather jerky and to squeak badly when used at slow speeds. (We have all heard garbage trucks with their disc brakes screeching in the morning) Because of this most manufacturers still used drum brakes on most cars and they used disc brakes only on sports cars. Engineers wanted the more powerful disc brake systems to work on street cars so they redesigned the brake systems many times to make them work better at low speeds and to make less annoying noises. Today almost all front brakes on cars and trucks are disc brakes. Almost all cars and trucks with an engine size over 2 liters also use disc brakes in the rear of the vehicle as well.

What Is A Brake Booster And Why Do I Need One?

When cars were first invented they were mostly driven by only men. You had to be strong to start them, strong to stop them, and strong to turn them. As cars and even trucks progressed more women started driving and also children started driving at an earlier age. Electric starters were added to cars. Soon after cars started using a hydraulic steering system which engineers named power steering. Soon after this engineers decided that they could shorten the brake pedal, (and the mechanical advantage the long lever offered) allowing shorter people to drive cars and trucks. The systems using this shorter brake pedal with less travel were named power brake systems.

Power brake systems use a device called a brake booster to help you push the master cylinder piston and actuate the brakes. There are several types of brake boosters used in cars and trucks but the most common is the rubber diaphragm power brake booster. When you apply your foot to the brake pedal the pedal moves the brake booster input rod and a valve in the brake booster opens up. Engine vacuum which has been stored in the brake booster pulls against a large diaphragm. As the diaphragm travels towards the master cylinder from this vacuum force a rod called the brake actuator rod pushes against the master cylinder piston. The master cylinder piston then forces the brake fluid through brake lines to the other components of the braking system with greater force than would be gained if you only used mechanical leverage.

Hydro-Boost And Other Hydraulic Brake Boosters

When cars and trucks used carburetors stealing a small amount of vacuum from the engine didn't really cause any problems with performance. Problems with this system generally started when diesel engines became more popular. Diesel engines do not trap vacuum behind the throttle plate the way gasoline engines do. Most diesel engines that use vacuum power braking systems had to have an external vacuum pump. This extra pump that pumped fresh air and pulled it into a vacuum for the vacuum brake booster. There was no real way for the impeller to stay lubricated or cooled and so many of these pumps produced unwanted failures in the power brake system. Turbocharged and supercharged cars and trucks had the same issues with low vacuum during periods where the engine was receiving boost instead of drawing air into the engine with vacuum.

A new system was devised using the pressure form the power steering pump. The hydraulic brake booster system operates in a similar manner to the vacuum brake booster system. The driver hits the brake pedal. the brake booster input shaft again pushes a valve but in Hydro-boost braking systems instead of vacuum acting against a diaphragm this valve releases hydraulic fluid pressure against a piston in the hydraulic brake booster. When the piston of the hydraulic brake booster is forced forward from the hydraulic pressure the brake booster piston moves the brake master cylinder actuator rod against the brake master cylinder piston. The brake master cylinder then pushes the brake fluid to the rest of the braking system to stop the car or truck. (If all of this sounds complicated you are not alone. in a recent survey less than 20% of all technicians replacing brake boosters could actually describe how they function internally. You would probably be better off just have Hendersonville Muffler and Brakes repair the braking system on your vehicle.)

What Are Brake Proportioning Valves?

With all of this extra equipment designed to help you exert pressure on the master cylinder and other brake components like disc brakes that began to give greater braking force to the wheels automotive engineers started noticing problems with the rear brakes locking up too easily. The engineers designed several small valve assemblies which would send a regulated amount of fluid to the rear brakes before it sent any brake fluid to the front brakes called brake proportioning valves. Proportioning valves limit the amount of fluid that travelers to the rear brakes in systems with front disc brakes and rear drum brakes when a large amount of pressure was applied by the brake master cylinder very quickly, (indicating a panic stop).

As I said before brake proportioning valves were originally just made to operate on vehicles that had front disc brakes and rear drum brakes. Some later brake proportioning valves were designed so that they had a rod attached to the suspension arm. As the rear suspension begins to rise the pressure is reduced to the rear brakes. This keeps the rear brakes from locking up during hard braking. Even though cars and trucks are now equipped with anti-lock braking systems, the braking system behind the ABS system needs to be capable of stopping the vehicle well without the use of the ABS control unit and pump system, just in case the ABS system fails.

As cars have become more complex and anti-lock braking systems have become mandatory the brake proportioning valve has often been incorporated into the combination valve. In the newest vehicles the brake proportioning valve has been replaced by a newer version which is called the Electronic Brake Proportioning Valve or EBP. On braking systems that are equipped with EBP valves the ABS unit controls the EBP valve.

Anti-Lock Braking Systems

Technology never stops and modern cars are now equipped with Anti-Lock braking systems. Anti-lock braking systems can be explained in greater detail here but this page is designed to explain the components of the braking system and ABS systems have extra components to operate correctly. ABS systems use wheel speed sensors, brake pressure sensors, transmission speed sensors, and valve assemblies.

I hope that this page has helped you have a better understanding and appreciation of the components needed for a braking system to operate but the truth is if you don't understand how all of these components work you should not be repairing your own brakes. At Hendersonville Muffler and Brakes we constantly study new technologies and we have a great understanding of how these brake components work. Remember that all of these components are part of the braking system. This is the most important system in any car or truck. Mistakes in the braking system may cause your car or truck NOT TO STOP when you want it to. Let the professional technicians at Hendersonville Muffler and Brakes handle all of your brake system repairs. Stopping when you want is much better than the alternatives