If one is driving and the car's brake fails, what is the next thing to do immediately?

Poster: STANCOBRIDGE | Date: 4:12pm, 13th Feb 2018. | Views: 73 | 1 Replies
Page 1 of 1
STANCOBRIDGE. Jalingo, Taraba
4:12pm, 13th Feb 2018.

Mechanical engineer, Alfa Romeo driver.

Here’s the short version:

Shift into the lowest possible gear that will not rev the engine beyond the red line. The drag from the engine and its accessories will start slowing you down gently. If it’s an automatic gearbox shift into “engine braking” mode, “low gear” or similar (sometimes indicated on the shift lever by letter “B” or “L” or “1”).

[Optional]: If your car has an air conditioner, turn it on at the coldest setting. The compressor draws power from the engine and will add another 3 horsepower of drag (to the 10–20 hp engine friction is already contributing) which will slow you down faster. If you have time and space, turn on all electrical accessories (lights, high-beams, fog lamps, heated front and rear windows, heated seats, blower etc.) as the alternator will absorb another 1–2 horsepower at full electrical load.

As the speed decreases, shift into progressively lower gears for more braking effect (always without over-revving the engine). An automatic will probably do this for you in the “engine braking” mode. With a semi-automatic (paddleshift) gearbox, just keep hitting the “down” paddle - it will automatically protect the engine from over-revving by refusing to downshift if the speed is too high for the next gear down.

Engine braking alone will take you down to about 5–10mph. To come to a complete stop, use the handbrake/parking brake. It’s normally cable-operated and completely separate from the main brake hydraulic circuits, so whatever took out the brakes probably didn’t affect the handbrake. To do this, hold the handbrake button and lift the handbrake lever slowly and progressively. If the rear wheels lock up (you hear the tyres dragging or you feel the rear end get loose), release the handbrake a little and try again. It’s easier than you think to stop a car using only the handbrake - I suggest you practice in an empty parking lot so you know what to expect if you ever have to do this for real.

If the handbrake is also broken for some reason, you can try stopping by getting progressively closer to the sidewalk/pavement until the sidewall of the tyres starts scrubbing against the edge of the pavement. This is a last resort though, there’s a good chance you’ll end up with a puncture, scratched rim, or body damage with this method. In theory you could also keep driving slowly in neutral gear until you encounter a slight uphill, or the rolling resistance from the tyres brings you to a stop. Then just maneuver to the side and steer the front wheels into the pavement (or away from the pavement if it’s an uphill) such that any up/down slope in the road causes the front wheel to drive into the pavement, thereby locking you in place until help arrives.

David Shastry

Creative Director | Powerlifter | Pilot | Senior Consultant

Don’t Freak out! Confidence and Control Saves Lives

This has happened to me before and while unnerving it wasn’t a completely terrible situation. The most important thing is staying in control of the situation the whole time; if you panic and make bad decisions, things go south very very fast.

Switch on your hazards
You must communicate to those around you that you are facing an emergency situation so they can clear the space around you. If you don’t indicate a hazard then you increase the potential of getting rammed into.

Try to get over to the rightmost lane (Slowest lane in the US)
The right lane usually has an emergency shoulder that you can proceed into in an emergency situation that is safe and clear of traffic ahead and behind you. In a severe emergency situation the shoulders are also equipped with energy absorbing devices such as crash cushions that can be relatively safer than slamming into moving vehicles. With no obstructions you can focus on modulating speed more effectively. Faster traffic moves left so don’t pull towards the left shoulder if possible.

Take your foot off the gas, pump the brakes
Once you’re in the right/emergency lane, try to see if you can build brake pressure by pumping the brakes a few times. If you see pressure building then slowly take your foot off the gas and use the brake pressure to slow the vehicle down. Why I don’t suggest doing this in the left lane is because if brake pressure starts to build without you noticing and you hit the pedal hard, there is a high chance of slowing down quickly and having vehicles behind you plowing into you from behind. Since you’ve declared an emergency, use an emergency lane for the maneuver. If you can’t feel any pressure in the brake pedal then use engine braking to retard the car.

Switch the car into manu-matic mode (if auto) and downshift
Manual transmission drivers know all about this. Use your vehicle’s natural engine inertia to slow it down. Watch your revs and downshift. With each downshift your vehicle will slow further. Stay clear of the redline to limit engine stress. Point the vehicle where you want it to go and downshift till you’re at a crawl. Shift into neutral, then engage the emergency brake/handbrake to lock the rear wheels and stop the vehicle. Do not shift into Park when the vehicle is moving/crawling as this can bend the parking pin and damage the transmission. Disconnect power to the wheels by shifting into neutral and then apply the parking brake.

I’ve successfully used this method to stop a vehicle before. I was going 75 mph when I lost brakes. I stayed calm and used this method to not only walk away from the situation but also not do any damage to the vehicle.

Most important thing is to stay calm. If you panic and yank the handbrake when you’re at speed, then you will end up creating a potentially fatal situation for yourself and others. Stay calm, be confident and guide the vehicle to a controlled emergency stop.

Daniel Wallander

studied at University of Wisconsin - Eau Claire

Take your foot off the gas pedal.

Pump the brakes, sometimes you can get some braking this way.

Steer around obstacles, use horn if necessary.

Shift down - either pull the gear into low1 on your automatic transmission or shift into successive lower gears on your manual transmission.

As you slow near a stop, steer to a safe place, apply the parking brake and turn the engine off. The car might stop rather abruptly, but it will stop.

Call a tow truck.

Gautam Jain

Bachelor of Technology from Indian Institute of Technology Jodhpur

The first and the most important thing which came to our mind should be how to stop that car.

There are several thing we should care upon

Never stop the engine. If you did this your steering wheen locked and leads to immediate accidents. Once my uncle told us his story in which some Delhi boys hit a man near the divider and that man fall on their car. Later it was found that there car’s steering was locked.

One of the best method to decrease speed is geardown. You must decrease the gear number forcefully leads to decrease in speed.

Try to move car left and right in a zig zag pattern, it provides more friction and hence helps us stopping the car.

We can do anything that reduces speed like rubbing the car against the guard rails helps a lot.

If one side of road has dirt or small plants than running car on these things also helps.

Blow horns continuously and turn alert lights on which alerts other drivers that something is wrong with you.

At last don’t panic and handle the situation wisely. You can call emergency too.

Timothy Mauch

Corvair owner and researcher.

The FIRST thing you should do, that nobody has even mentioned, is to pump the brakes (brakes, not breaks, people!) to see if they have totally failed. I’ve had that happen a few times in very old cars with a brake leak. Pumping may build-up enough pressure to make something happen before trying the other steps.

Also, you may not have had a brake failure. If something happened to the power-assist system, it may SEEEM like you have no brakes (because nothing seemed to happen when you pressed the pedal with a normal amount of pressure). You just have to push very hard on th pedal to actuate the brakes.

Plus, a TOTAL brake failure is pretty rare, because all cars built after 1964 (in America) have a dual-brake system. There are two completely separate hydraulic systems, each one acting on two wheels. You have to push harder to slow down, because you only have half of your brakes.

If you have been going down a long, steep road (in the mountains) and using constant brake pressure (bad idea), you may have overheated your brakes. Down-shifting is your only good procedure (the emergency brake may, or may not be an entirely different mechanical system. Even if it is, the brake drums may have been overheated by the heat from the regular discs.

One time, my master cylinder had an internal leak. The pedal felt just fine, but the brakes didn’t do anything. I was only going 5 MPH, entering a parking stall, and didn’t have time to do anything but hit the wall of the 7–11 with my truck!

The most important thing to do, is practice these various steps in all of the answers BEFORE you ever have a problem. In the military we call it “muscle memory.” If you practice it enough, when it happens, you’ll do it without even thinking about it, first. It seems like it goes from your eyes, directly to your hands and feet, without passing through your brain (seems, I said).

Francois Dovat

Automotive tech writer, former racing driver, former trucker

A sudden and total brake system failure is as unlikely as your modern car metamorphosing into a horse… because cars produced since the 1960′s have a dual braking circuit. In case of failure of one of these circuits, the other remains operational. In general, the distribution is diagonal, in "X": one circuit is connected to the brakes of the left front and rear right wheels while the other activates the brakes of the front right and left rear wheels.

If the brake booster fails, braking is still available by pressing stronger on the pedal.

But lengthy and heavy use of the brakes can lead to fading, either because the temperature of the pads exceeds their heat capacity, which is manifested by a characteristic burning smell, or because the brake fluid starts to boil, generating gas bubbles that softens and lengthens the pedal stroke to the point that it can go all the way to the floor. It is then possible to reduce its stroke to recover the use of the brakes by pumping, aka by pressing and releasing the pedal quickly several times.

Disc brake on a test bench. Temperature of the rotor and pads can reach 800°C

Brake fade can occur by braking too much while going down a long, steep hill or braking repeatedly several times from high speed, as it commonly happens in racing.

I never heard of sudden total brakes failures and it never happened to me in more than a million miles, nor to anyone I know. I’ve experienced sever brake fade in racing such that I had to pump with the left foot to get ready to brake before the next corner while still accelerating on the straight. But my brakes never failed completely.

Anyway, to answer the question, let’s suppose it happens. What to do in such a case? Obviously, one would only notice it when trying to brake! If there’s no emergency, then just slow down to a stop by downshifting and use of the hand brake - parking brake. If there’s an emergency, it’s possible to skip gears and downshift several at once. For example with my Renault Laguna 2.0 dCi, I can downshift from 6th to 3th gear at 125 km/h without over-revving the engine, as shown in the diagram below.

The parking brake - hand brake is usually mechanically operated by cables and would still perfectly work (but on the rear wheels only, except on some Citroën in which it works on the front wheels) in the extremely unlikely case that both hydraulic circuits would fail simultaneously.

An electric park brake (EPB) will work as an emergency brake as well. Here is what Jaguar Owner Information says:

In an emergency, with the vehicle traveling at more than 3 km/h (2 mph), pulling up the EPB switch and holding gives a controlled reduction in the speed, also release the accelerator pedal. This can be used to bring the vehicle to a complete stop. The EPB warning lamp flashes, a warning chime sounds and a warning message displays in the instrument panel. The stop lights illuminate. Releasing the EPB switch, or pressing the accelerator pedal, releases the EPB.

I tried on my Laguna and it’s exactly that.

Page 1 of 1
Write A Comment

Attachment: (jpg, gif, png)

Comment Box is loading comments...