Causes of Brake Failure And What You Should Do When Your Brakes Fail When Driving?
Common Causes of Brake Failure?
Brake failure in an automobile can be serious, and each year leads to hundreds of car accidents. Some of these accidents result in serious injury or death and in all likelihood could have been avoided if the driver had noticed the signs of brake failure. Let’s consider the seven most common causes of brake failure in cars today.
Owner Neglect
The most common cause of brake failure is owner neglect. Brakes, like many other parts of an automobile, have a limited lifespan and should be occasionally inspected for wear. Although many brands of brake pads and shoes boast a long life, this estimate is based on standard driving patterns. If you find yourself constantly stopping and going in cities or neighborhoods, the life of the brake pads and shoes will be greatly reduced.
Overheating Brake Pads
Brake pads can overheat due to excessive use and become hard or brittle. This hardening decreases the ability of the pads to properly grip the wheel rotor disk, increasing the distance necessary to stop the car.
Damaged Rotor Disks
Damaged or “scored” rotor disks on the wheel can decrease the life of your brake pads, making stopping more difficult. Have your rotor disks smoothed or “turned” by a trained mechanic when your brake pads are replaced.
Leaking Hydraulic Fluid
Oil or other hydraulic fluid can leak from your car’s engine or brake lines. If you find stopping has become difficult, have your brakes inspected to rule out any contamination from a leaking hydraulic line.
Driving Through Mud or Water
Driving through mud or water will naturally “lubricate” your brake pads and rotor disks. Gently tapping the brakes can help remove excess water and re-establish the proper friction between your car’s brake pads and rotor disks. As always, use caution when driving in wet conditions, especially when your car’s wheels are partially submerged in water.
Loss of Hydraulic Brake Fluid Pressure
Loss of hydraulic brake fluid pressure will decrease your ability to stop quickly. If you find your brakes do not seem to work at all or are working only modestly, tap the brakes several times to help force fluid throughout the brake system. Though effective in helping stop your car, this technique should not be used unless absolutely necessary. Have a certified brake specialist check your brake system for any leaks and refill the reservoir with brake fluid.
Overloading Your Automobile
Overloading any automobile will change its ability to stop and can potentially damage the braking system. Only load your car as suggested by the owner’s manual.
The Design of the Discs or Drums
The heat generated by braking must be dispelled quickly. When disc brakes have a more open design, it becomes less likely to overheat. It is only natural for the discs to be at the front, generating most of the braking action. Meanwhile, the cheaper drum brakes will be on the rear, providing the brake function when you park. On the other hand, when you’re looking at larger or high-performance vehicles, you will notice that all four corners have disc brakes.
Insufficient Air Pressure
If the brake pedal goes all the way to the floor when you press it, it is likely that there is something wrong with the air pressure. When you step on the foot brake, the air used must build up quickly. Keep in mind that when the pressure drops too low, you should pull over to safety and avoid attempting to drive the vehicle. No matter the speed a car is traveling, such situation will put your life at risk.
Corrosion
In most cases, brake failure is caused by corrosion in various parts of the brake system. Here are some pointers to remember:
1. Ideally, cast iron is the suitable material for brake parts. However, it can rust quickly.
2. The action of the disc pads can quickly clean off the surface rust on the front. However, this may not be the case on the rear drum brakes, especially on small, light vehicles or cars that are not used frequently.
3. The rear drum brakes do not typically experience corrosion issues.
4. Heavy braking can clean off initial, light corrosion. However, if neglected, this light rusting can get worse and cause surface pitting.
5. Before, pitting is one of the causes of MOT test failure. These days, the only reason why discs fail the test is when they’ve become ‘seriously weakened’.
Daily Wear and Tear
1. Eventually, the front discs start to wear out and they end up becoming too thin.
2. It is worth noting that manufacturers specify the indications that tell you when you need to replace the discs. It is advisable to change them in pairs.
3. At the same time, you must replace the pads.
Distortion
1. The disc’s shape can change because of uneven cooling and heating.
2. When you feel shakiness coming from the pedal, it means that your discs are distorted.
3. Keep in mind that worn out or thinner discs are more susceptible to warming.
4. Ideally, you should keep yourself from holding the vehicle back when you are going on long downhill stretches. Otherwise, you will subject the discs under tremendous heat. Instead, you should use engine braking and place your car to a lower gear.
What should you do if your brakes fail while you are driving?
Depending on what vehicle you are driving and the type of road you are driving on, you have a number of options if your brakes stop working while you’re driving.
They could stop working because of brake fade, you’ve driven through water, or a mechanical issue. If you lose your brake fluid, the brake warning light will appear on your dashboard.
Sudden brake failure is extremely unlikely. Even if your power-assisted brakes fail, you can still usually apply braking power by pressing harder on the brake pedal.
In some countries there are emergency escape lanes on long downhill stretches that vehicles that experience brake failure can use, but they are not everywhere. Let’s talk about predominantly flat roads first, though.
Get out of the way of other traffic
Other traffic needs to know what you are doing, so your indication is important. If you need to move to the left off the road or across lanes, signal left and try to move into a gap.
On a motorway with a hard shoulder, try to get to the hard shoulder as there is less likely to be anything in it for you to hit as you slow down.
Pump the brakes
If the pedal goes to the floor, pump it a few times then push it to the floor. There might not be much braking, but anything is better than nothing.
If the pedal feels rigid, is there anything lodged underneath it, like your floor mat?
Give clear signals
Putting your hazard warning lights on will let other drivers know you are experiencing difficulties. Use your horn.
Use your gears
Lower gears provide more engine and mechanical resistance – this is called engine braking. Be careful not to over-rev the engine, though. You may need to step down through your gears as you lose speed. In a car with a manual gearbox, this is straight forward. In a car with an automatic gearbox you might have an L setting, or you could have sequential-style gears where you can change down with paddles behind the steering wheel, or a gear lever. Simply keep changing down a gear every time the revs drop to a couple of thousand below the red line.
Engine braking will reduce your speed to 5-10km/h but no more – your car will continue to creep forward.
Don’t put your car into reverse while you are going forwards because you risk causing a huge amount of damage to your gearbox.
Turn on the air conditioning and accessories
The air conditioner should be turned onto the coldest setting with the highest fan speed. This will absorb a couple of kilowatts of power. Turning on all accessories, such as the heated rear window and your lights, will also create some drag on the alternator.
Use the handbrake
Don’t pull the handbrake on at high speed because you risk spinning out. There’s also the risk that it could overheat and become ineffective. Wait until engine braking has dropped your speed to below around 20km/h, then pull the handbrake on gradually. The handbrake only works on the rear wheels and if they skid you could lose control, so be careful.
If you have a newer hydraulic handbrake/electric parking brake most modern cars will perform a controlled deceleration if you hold the switch on.
Brake failure while towing
Some trailers have separate trailer brakes which might be able to be applied. If the trailer is fairly light, it won’t slow you down quickly, but it will help.
Engine braking
Trucks often have compression release engine braking which uses pressure in the engine to slow a vehicle down.
Use the road contours
If you see a side road that is uphill, you can turn up it to stop more quickly.
Use kerbs and the edge of the road
Gently running your wheels against the kerb won’t do wonders for your tyres or alloy wheels, but it will create extra friction. The same applies for concrete dividing barriers on motorways.
Grass verges will create more resistance, but they will increase your risk of spinning out.
Hedges and bushes will damage your paintwork, but have been used before in an emergency.
Rough stone walls are not so good as the corner of the vehicle will catch on the wall and it will spin it around (or flip it over) like this.
Electric vehicles
Electric vehicles have regenerative braking and this provides a level of resistance which is used to charge the battery. Many electric vehicles have a ‘B’ mode (sometimes even B1, B2, B3, B4, etc) to indicate how much regenerative braking will be used. Use this mode if your brakes fail; in some electric cars, the highest setting is as good as applying your brakes moderately.
Steep slopes
If you’re on a very steep slope, engine braking might only slow the rate of acceleration, i.e. you’ll still pick up speed, just less slowly. If you change gear, your car will pick up speed while the gearbox is between gears.
It’s critical you act quickly in this situation. You need to make a decision:
Can I ride out this bit of the hill then deal with actually stopping when the gradient levels out, or do I need to stop now?
The only reason you’d choose the first one is if you know the road, the rate of acceleration isn’t high, there’s not much traffic around and you’re confident in your vehicle’s ability.
If it’s the second one, you have a number of options to help you:
• Verges, hedges and bushes will slow you down; trees will stop the car dead unless they are saplings
• Escape roads are the best option
• You can (gently) run into the back of a bigger vehicle which will then brake and slow you down. But, be careful you won’t create a much bigger accident
Things not to do if your brakes fail
• Don’t put your gearbox into neutral or you’ll have no engine braking.
• Don’t put your gearbox into reverse unless you want it to be converted to thousands of tiny metal shards (and you’ll have no engine braking).
• Don’t weave from side-to-side at high speed. Yes, it creates more friction, but you risk spinning out, and if your brakes have failed, any electronic stability control measures (which work by braking individual wheels) might not work. At low speed, it’s probably fine.
• Don’t stop the engine – you’ll lose your power steering
When you’ve stopped
Hopefully you’ve managed to pull off the road and out of the way of other traffic. Put your hazard warning lights on. If you’ve just overheated your brakes, you can wait for them to cool, then limp home at a slow speed. You will need to change your brake fluid and gets the brake rotors and pads checked (you may have glazed the pads which will make them much less effective). If there’s something wrong with the brakes, get your car towed.
In brief: what to do if your brakes fail
1. Get out of the way of other traffic
2. Pump your brakes
3. Give clear signals
4. Use your gears
5. Use your handbrake or electronic parking brake
6. Turn on your air conditioning
7. Look for uphill escape routes
8. Use kerbs, verges and bushes
Comments (4)
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Hmmm? thanks for this article.-
Every day I ask my mechanics how to avoid brake failure and i keep getting same reply. thanks so much for this write up.
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Thanks for your comments
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