Our Current Blog Articles
March 14, 2017
What's the Difference Between Drum and Disc Brakes?
Today, South Denver Automotive is answering a frequently asked question, what’s the difference between drum and disc brakes? We’ll also explain a little bit about the dynamics of braking. As with anything in the automotive industry, car manufacturers are always seeking ways to improve braking systems and offer greater stopping power and safety in today’s vehicles. Since the 60s, however, there have been two main types of brakes used, drum brakes and disc brakes.
The goal of brake research and development has always been to improve stopping power and make vehicles safer to drive. It has been a constant quest for many years, and the designs have improved by the addition of better performing materials like sintered metal, carbon fiber, and a lightweight version of steel as well as the introduction of systems like ABS (although the effectiveness of that is still up for debate).
Through it all, however, one thing has remained constant. Disc brakes have always proven to be a more effective design than drum brakes. Now, of course, today’s drum brakes have been significantly improved over earlier models and are better than the early disc brake designs. However, the disc brake design has also improved proportionately, so it still comes out as the leader.
Now, if you know anything about cars you probably know that both types of brakes are in use today, which begs the question, if disc brakes are so much better why not just use them exclusively? The answer, quite simply, comes down to cost. Drum brakes are significantly cheaper to manufacture, and that makes it worth it both for manufacturers in their production costs and consumers with the resulting purchase price.
But should cost be such a concern when it comes to safety? Probably not, but everyone knows that in the real world, price still comes into play regardless. Plus, the way that drum brakes are incorporated into modern cars does not diminish their safety or braking ability by much.
What it boils down to is that between 60-90% of your stopping power comes from the front tires of your vehicle. So, it makes sense to put a set of disc brakes on the front wheels, and drum brakes on the back, to create a vehicle that’s both cost-effective and safe. In many high-performance cars, especially the type used for racing and activities of the like, it is worth it to install a four-disc brake system. However, four disc brakes are overkill and add unnecessary cost for the average everyday driver.
The Principles of Friction and Heat
Now that we have established that disc brakes offer more advanced stopping power than drum brakes, let’s talk about why. Both systems rely on friction and heat to slow your vehicle. Both designs use brake pads to apply resistance to the vehicle’s wheels, thereby creating friction that will eventually stop the vehicle. How quickly depends on a variety of factors including the vehicle’s weight, total braking surface area, braking force and heat transfer. The heat transfer part is important for us because that’s where the difference between drum and disc brakes comes in.
Now, as anyone who has taken a high-school science class can tell you, heat is a byproduct of friction. In autos, it's the reason why oil changes are so important, to keep engine parts lubed and moving freely instead of building up heat that can damage your car engine. So, when you are braking and applying all that resistance to the wheels and causing all that friction, the natural byproduct is heat. If that heat remains trapped near the wheel for long enough, the brakes will become too hot and start to fade. Stopping power will be significantly diminished as a result.
Now that you understand the importance of heat transfer, let’s look at the difference between drum and disc brake design. Even just a quick look will explain why disc brakes do their job so much better than drum brakes do.
Modern braking systems began with drum brakes. The oldest designs (after hand levers) incorporated drum brakes on all four wheels. They get their name from the drum-like housing in which resides the brake shoes. When you press on the brake pedal, hydraulic fluid is used to force the brake shoes against the drum and cause the wheel to slow down.
Of course, the components are made of heat resistant and heat wicking materials that help to move heat away from the drum as quickly as possible. But it’s not perfect, and as we mentioned, once it gets too hot, the shoes begin to slip and your stopping power diminishes.
Under most normal conditions this is never a concern. But if you put your vehicle in a high-stress braking situation such as constantly braking as you drive down a very steep hill, or stopping from a high speed repeatedly, you will notice a marked decrease in braking performance.
Disc brakes operate on the same basic principles as drum brakes, but the structure is different. Instead of a drum, the disc brake has a rotor and a caliper. Two brake pads reside inside the caliper. When the brake pedal is pressed, hydraulic fluid is again used to move the brake pads and force them to clamp together.
This is where the difference comes in. In a drum, the brake pads and resulting heat buildup are all trapped inside the drum, slowing heat transfer dramatically. The rotor design, however, is more open and exposed to the surrounding air. That moving air carries away heat much faster, and therefore disc brakes have a much lower chance of overheating and fading.
Again, this is why it is not considered unsafe to use drum brakes on the rear wheels to cut costs. The brake is still a good design and will only fail in rather extreme conditions. The rear wheels are never subjected to as much force as the front wheels when it comes to stopping power, so it is unlikely they will ever overheat. Even if they do, the front brakes will most likely still be going strong, and you will have the stopping power you need to slow your vehicle safely.
We hope this article has been helpful and you now have a better understanding of what’s the difference between drum and disc brakes. Of course, you can always contact South Denver Automotive with any questions and our experts will be happy to answer them for you! Also, don’t forget to have your brakes checked once in a while to ensure that you are safe out there!
February 24, 2017
All about your car engine’s oil
Many people might not know all about your car engine’s oil, but they at least know that it performs a vital function. Responsible drivers are also aware that they need to have their oil changed every few thousand miles and keeping an eye on the oil level is one of many essential preventative maintenance measures that they can take. Letting a car engine run out of oil and having to pay the resulting repair bill is usually something you will only do once.
Here at South Denver Automotive, we know all about your car engine’s oil so you don’t. In today’s busy world, who has time to be worrying about pesky things like proper oil viscosity and performance? On the other hand, if your inquiring mind is curious to know all about your car engine’s oil then keep reading this article to pick up some interesting and even important pieces of information.
What is the big deal about engine oil?
First of all, what makes your car engine’s oil so important? Why is it such an integral part of your cars preventative maintenance and what terrible thing will happen if you fail to provide adequate maintenance?
To answer this question, it is not necessary that you intimately understand all the inner workings of your car’s engine. Even if you have the most rudimentary understanding of motors, you probably know that as an engine works, many moving parts are involved in the combustion process that propels a vehicle.
High school science explains to us that when parts are moving around and against one another, friction is produced, which in turn produces excess heat. Just like when you rub your hands together on a cold day to warm them up. But engine parts are rubbing together a whole lot faster and producing a whole lot more heat. In addition to excess heat, parts constantly moving against one another will rapidly cause extensive wear and tear that will quickly destroy said parts and leave your engine crippled and you stranded on the side of the road somewhere.
That’s where the oil comes in. Engine oil is specially designed to thoroughly lubricate the moving parts inside your car’s engine, thereby drastically reducing both excessive wear and excess heat. Plus, as an added benefit, engine oil helps to keep your engine clean by washing away the chemicals and contaminants that naturally occur as a byproduct of the combustion process.
But don’t just buy any old engine oil. Not all oil is created equal, and you should be aware what type of oil is recommended for best results with your car’s engine. Of course, a reputable service center like South Denver Auto will be able to get that information for you if you don’t want to bother with searching for your engine manual.
What is the API Certification Mark?
In addition to ensuring that you choose the right type of oil for your car’s engine, you should also be aware of the API Certification Mark, also known as the starburst because of how the logo looks. In general, car manufacturers recommend that you look for this mark on the oil that you are considering putting into the engine.
Why? The American Petroleum Institute, or API, only puts this mark on oils that meet the current engine protection standards and fuel economy requirements put forth by the International Lubricant Standardization and Approval Committee, or ILSAC. Both American and Japanese automobile manufacturers are behind the production of this committee’s standards.
What is the API Service Symbol?
Another mark to watch out for is also issued by the API. This Service Symbol, or the Donut as it is called, contains three important parts.
- The performance standard: A code depicting the particular API performance standard met by that oil. Codes beginning with ‘S’ refer to gasoline engines and codes beginning with ‘C’ refer to diesel engines.
- The viscosity grade: Viscosity refers to the thickness of an oil and its ability to flow at differing temperatures. Each engine oil receives a different SAE number representing its viscosity. Be sure to use the oil viscosity that is recommended by your car manufacturer for best results.
- Energy conserving: Oils that meet the energy conservation requirements for gasoline engines bear this part of the mark and could potentially mean savings for you in fuel economy.
Why should you change your oil periodically?
As part of the process of performing this vital function of lubricating and cleaning your engine, elements of the engine oil are used up over time. The only way to replenish these necessary elements is to change the oil. Plus, remember that the oil is constantly cleaning the engine and flushing foreign contaminants from the engine. Those contaminants remain in the oil until it is drained and replenished, so it is important to do it regularly.
How often should you change your oil?
That depends on a couple of factors, mainly the type of engine your car has and the driving that you typically do. If you often drive in severe driving conditions, you will have to replace your car engine’s oil more frequently. Check the manual for your vehicle’s engine to get the manufacturer’s recommendations as well as the definition of severe driving conditions for that vehicle.
To give you an idea, typical conditions that are considered severe include:
- Extremely dusty conditions
- Extreme temperatures, both hot and cold
- Stop-and-go driving
- High-speed driving
When in doubt it is always better to err on the side of caution and change your oil sooner rather than later. Engine oil is extremely inexpensive when compared to the cost of repairing damages caused by not changing your oil frequently enough.
Of course, you don’t need to be an expert in engine oil to work out the appropriate oil change schedule. Consulting with a reputable mechanic like South Denver Automotive is a great way to find out how often you should have your oil changed and what kind to use.
We’ve been providing full-service auto repair since 1990, and you can be sure that we know all about your car engine’s oil. We keep up to date with all the latest developments and yet have been around long enough to know what to do with older cars that come into our shop also. Whenever you need good all-around service that you can trust, be sure to bring your vehicle in for us to take a look, at South Denver Auto.
January 15, 2017
The Basics About Car Brakes
As a responsible car owner, it isn’t necessary that you understand the ins and outs of every component in your vehicle and how it functions. You just need experts like our team at South Denver Auto to help you when things are not quite right with your car. Of course, having some insight into your vehicle, such as knowing the basics about car brakes, can go a long way towards catching your car brake problems before they get to be too big, and in some cases even preventing a dangerous situation.
Your car’s braking system is a crucial aspect of safety. Brakes that suddenly stop performing well or go out completely at an inopportune moment (any moment, really) can put you and your passengers in a highly dangerous position. It might sound dramatic, but knowing the basics about car brakes may save your life. So, let’s get into your system and how it works.
The likelihood of your brakes suddenly going out is low, particularly if you are diligent about taking your car to a reputable shop like South Denver Automotive and having it checked periodically. In fact, preventative maintenance is the number one way of limiting the need for major, costly repairs and ensures that the necessary systems in your vehicle are running up to par. However, it is possible, and if you know the basics about car brakes, you will better understand the warning signs.
First off, it will be useful to learn a bit of vocabulary and better understand what different parts of the braking system are and how they are used. This, of course, will be especially useful for those who may not have a good understanding of car parts and or what they are called.
Brake Fluid: This is a vital part of the system. This type of hydraulic brake fluid is used primarily in cars and light trucks. It follows the same idea as anything hydraulic and is the fluid used to transfer force between the hydraulic lines and the braking mechanism. This fluid has to be able to withstand high temperatures as a vast amount of heat is produced during the braking process. Plus, your brakes must not solidify in freezing temperatures but continue to work well in the cold temperatures of winter.
Disc Pads: These consist of various types of compounds that are noted for their ability to create friction. These compounds are then attached to a metal plate.
Rotor: This is a metallic disc located inside the wheel and is able to rotate with the wheel. When the car brakes are used, the disc pads are pressed against the rotor, and the resulting friction is what slows or stops the vehicle.
Caliper Assembly: Caliper bolts are used to connect this assembly (which consists of the caliper piston, seal, and dust boot) to the steering assembly and align the brake housing correctly with the brake rotor. The hardware used also provides a surface over which the caliper can move across the bolt and keep the brakes together right where they should be.
Wheel Bearings: Keeps everything (the rotor, the disc pads, and the caliper assembly) aligned correctly and allows for the wheel to rotate freely.
Wheel Stud and Lug Nuts: Of course, you need to have the little hardware pieces that support the wheel and tire and keeps it securely connected to your vehicle.
Brake Drum: This is a metal cylinder inside the wheel, similar to a rotor. In this design, brake shoes are used to press against the drum and slow the vehicle. Brake shoes are also metal plates with various high friction materials like brake pads.
Wheel Cylinder: Consists of springs, seals, pistons and dust boots.
Backing plate: A surface for mounting the shoes and allowing them to slide. It also holds down hardware and the wheel cylinder.
Hardware and Springs: These are used to pull each part in the braking system back to where it should be, after releasing the brakes.
Now that we understand some terminology and the basics about car brakes a bit better, let’s look at the two main types of brakes, disc and drum brakes. Of course, all brakes perform the same function in the end, but there is a difference in how that function is performed. So, let’s take a moment and learn more about the two types.
So called, because they consist of a disc or rotor with a caliper assembly, wheel bearings, disc brake pads and the other necessary items for mounting the parts on the vehicle and keeping everything where it should be. A network of tubes, hoses, and valves are used to connect the caliper to the master cylinder and conduct the necessary brake fluid through the system.
These consist of the other components mentioned. The drum, brake shoes, wheel cylinder, backing plate, and springs. This type of system also has a network of tubes, hoses, and valves, that move the brake fluid through the system.
Anti-lock Braking Systems
This is an important electronic braking system that is available for most vehicles. The function of this system is to aid in safe braking. While you apply pressure to the brake pedal, the ABS is monitoring each of the wheels. If it notices that one wheel starts to move slower than the others it lessens the pressure to that wheel. The wheel begins to speed up, and the ABS puts pressure on it again to prevent the wheel from moving too fast.
As you can imagine, this is immensely helpful in all driving conditions, but particularly in winter driving conditions. When one or more of your tires is hitting the ice, the ABS will help to keep even speed on all your wheels thereby preventing a spin out. These systems are extremely sophisticated and can make changes in pressure 20 times or more in a second. As a result, you might feel a pulsing sensation through the brake pedal while this system is engaging.
As mentioned previously, you don’t have to understand all the ins and outs of your vehicle intimately. The friendly experts here at South Denver Automotive are always willing to help you out with questions or examine your car if you think there might be something wrong. Knowing a few things, like the basics about car brakes, is helpful because you are the one driving your car every day and thereby the one who has the earliest and best chance of detecting an issue before it gets to be a serious problem.
December 23, 2016
Car Maintenance for Your Vehicle at 50k, 100k, 250k Miles
To keep your car in good running shape there are a few things that you should be sure to keep up. South Denver Automotive presents this list of items that should be checked or replaced every 5,000 miles along with essential car maintenance for your vehicle at 50k, 100k, 250k miles.
Cars these days last much longer than they did before. It used to be that once they reached the triple digits in mileage, they were getting close to needing a lot of bothersome repairs. However, that has changed. Now cars are routinely getting well over 100k and are still going strong.
They don’t just magically keep running, however. There are a few things that wise car owners can do to maintain the engine running smoothly and avoid any major mishaps on the road.
As part of a regular maintenance routine, there are some things that you should have checked out approximately every 5,000 miles:
- The engine and oil filter. However, be sure to consult the owner’s manual because some cars can do with an oil change every 15,000 miles.
- Rotate and balance tires. This will even out wear thereby making tires last longer and lessening vibration.
- Examine the brakes. It is very dangerous to operate a vehicle with inadequate brakes. Remembering to check for wear when you have the oil changed is an excellent way to keep on top of this critical system.
- Check all the fluids. In addition to the oil, it is a good practice to check all your fluid levels whenever you stop in for the oil.
- Make repairs quickly. When you hear something strange in the engine, or you think that something isn’t right, get it checked out and repaired quickly. This will keep the damaged part from causing more damage in the long run.
Around the 50K mile mark, there are a few extra things you should have checked. The engine coolant may need flushing. Although some cars now have a coolant that is good until 100K, so check your owner’s manual to see which type you have. Other things that should be monitored include:
- Spark plugs
- Drive belts
- Radiator hoses
- Struts and shock absorbers
- Suspension alignment
Once you make it to 100K miles, there are some more maintenance things to be aware of. If you didn’t replace the coolant at 50K, now is the time. The timing belt will likely also need to be replaced and possibly the water pump.
By the time you hit 250K miles, you’ve got a good idea of what your car needs and when. If you make it to this mark, then you apparently have provided fantastic car maintenance for your vehicle at 50k, 100k, 250k miles, so keep up the good work!
Here at South Denver Automotive, we are available to call if you have questions or other concerns. And, of course, you can always call us to perform any of these routine inspections and repairs. We’ll keep your car in tip-top shape so that you can always depend on your vehicle.
December 13, 2016
Should I Repair or Replace My Car Transmission
Car owners are always less than thrilled to hear that there is something wrong with their transmission. If you have recently received this news, you may be asking yourself should I repair or replace my car transmission? South Denver Auto would like to help you with that question today, offering these pros and cons of repairing or replacing your transmission.
Rebuilding your transmission
First, what happens when you have a transmission rebuilt? A qualified technician will take apart your transmission and thoroughly inspect all the parts. They will replace anything that is damaged or just plain worn out. They will also ensure that your transmission meets current factory specifications.
One of the biggest pluses of this method is that it will completely update your transmission with parts that were made to address weaknesses with the initial design of the transmission. Therefore, you could potentially end up with a transmission better than it was before, and better than one that you could buy new.
One of the biggest minuses is the time that it takes. Even an experienced professional will need to perform hours of work to correctly disassemble, thoroughly inspect, replace parts and reassemble your transmission. It is also crucial that you find someone that knows what they are doing, otherwise you could end up with a massive bill and a transmission that either doesn’t work or is only so-so.
Replacing your transmission
Your other option is to purchase a replacement transmission and have that installed. Unfortunately, you can’t necessarily buy a new transmission, those pretty much only exist in new cars. Instead, you will purchase a transmission that has already been rebuilt in the factory.
The biggest plus about this is purchasing a transmission and installing it is much faster than rebuilding it. If you’re short on time and need your car back on the road as quickly as possible, this is probably the way to go.
You might be thinking, why not simply buy a new transmission? That way, the installation will be faster, and I will end up with a rebuilt transmission. The downside occurred when that transmission was rebuilt. It might have been sitting on the shelf for a couple of years, meaning that you won’t get the benefit of all the newest updates and fixes.
Ultimately it can be situational as far as which method is best for you. Just be sure to have a chat with a knowledgeable technician to help you determine the best route for you.
Here at South Denver Auto, we are always happy to help and answer questions. We hope this article has helped answer your question, should I repair or replace my car transmission? We know that in today’s world reliable transportation is imperative to our customers. Our goal is to get you back on the road as quickly and efficiently as possible.
If your car is having issues, be sure to give us a call today and bring your vehicle in for a checkup. Our knowledgeable staff can help with a variety of auto problems, and we do it all with a friendly smile!