[vikram_d]

The first and most important thing to do is to stay calm and not panic. I know this is easier said than done but being calm helps make better decisions. Then follow all the tips given by folks earlier.

[Gansan]

I was given to understand long back that cars have dual circuitry for braking i.e.left front+right rear and vice versa, so you can never lose the brakes completely. Is that true or not?

[SS-Traveller]

Originally Posted by Gansan

I was given to understand long back that cars have dual circuitry for braking i.e.left front+right rear and vice versa, so you can never lose the brakes completely. Is that true or not?

True. However, it only minimises chances of total loss of braking in case of leaks from pipelines leading to the wheels. In case of servo failure or total oil loss from reservoirs, both circuits stop working.

[dhanushs]

Originally Posted by SS-Traveller

True. However, it only minimises chances of total loss of braking in case of leaks from pipelines leading to the wheels. In case of servo failure or total oil loss from reservoirs, both circuits stop working.

Even in the case of servo failure, mechanical linkages does work, right?. You just need to stand on the brakes (?).

[SS-Traveller]

Originally Posted by dhanushs

Even in the case of servo failure, mechanical linkages does work, right?. You just need to stand on the brakes (?).

That's right. The hydraulics continue to work, but with sudden loss of assist, it feels like they are not. Which is why my suggestion of standing up on the brake pedal.

[honeybee]

Originally Posted by Daewood

Wouldn't the engine RPM come back to lower levels as programmed in the ECU after the momentary initial increase, since the feet is not on the accelerator?

On a descent, I don't think so. Or even if they did come back down, it would still take a lot of time. Which is why downshifting alone wouldn't help on a descent.

Yes, I missed another point. Switching off an engine is a cardinal sin in such occasions. You will lose all power, the steering will become hard, the brakes (whatever fluid left in the system) will become hard and forget about engine braking. So never switch off the car engine.

To make sure it doesn't occur suddenly, make a habit of checking the brake fluid level regularly and get the brakes (pads and liners) checked / replaced periodically. The intervals are already given in the respective car owner's manual. But if you drive in abnormal conditions or your usage is heavy, you can merge it with your periodic servicing or oil change. Of course, watching out for any abnormal braking behaviour of the vehicle would also help a lot.

I had an issue with my car where in the event of an emergency braking, the car wobbled, the rear swung out left and right and it was by sheer luck I missed ramming into the back of an autorickshaw. I got the brakes checked and the front pads had worn out. Got them replaced. Over a few weeks I had also been observing that whenever in the stop-n-go traffic while descending a flyover I engaged the handbrake, the moment the vehicle stopped there was a screeching metallic noise. Again got the drums opened and found that the rear brake oil cylinders had started leaking oil. Got the cylinders replaced.

Whenever you get the brakes checked, do also make sure you get the handbrake checked and adjusted.

[pacman2881]

Originally Posted by nukeblitz

So, what of switching off the engine? Don't do it if you are travelling at high speeds. Since most of our cars are front wheel drive, that could cause the *front* wheels to lock. Your steering wheels getting locked is a very very BAD THING. Once you get locked into that kind of slide, with your engine switched off, regaining control in time is improbable. It's either crash or you get lucky and you stop.

Originally Posted by anupmathur

NukeBlitz, this is completely incorrect! Switching off the engine will most certainly not cause the front wheels (or rear wheels in rear wheel drive cars) to lock!
Switching off the engine is not advisable for different reasons, like loss of power assist to the steering and servo-assisted brakes.

I think nukeblitz is referring to steering getting locked when you switch off the engine. I have seen steering getting locked after the engine is switched off and it is a bad idea in emergency situations.

[YaeJay]

^^ No he was referring to steering becoming suddenly heavy and brake pedal becoming heavy after a couple of applications.
Steering lock happens only if one pulls out the key, well used to like that in almost everything i've driven!
I've had quite a few scary movements, in different set of wheels. Try to rev match down shift clutch declutch in a rapid motion to enable faster downshifts, in older ( hmm to most here it should read OLD) petrol cars turning off the ignition, if your on a truck/SUV, you might have to ram your sides gently on to some sidewall and gradually bring it to a halt.


It all depends on the situation, what you are driving and how much space one has before stopping.

But the most important survival ingredient would be not to loose your cool and panic.

[clevermax]

While downshifting is something you must do, pulling handbrake will have varying results from car to car. In some brands and models, hand brakes are so effective that it can lock the real wheels instantly, while in some others it just helps preventing the car from rolling from standstill but may not be effective at all while car is on the move.

But locking the rear wheels at good speeds can initiate a drift, so downshift and reduce the speed to around 30-ish, and then pull the hand brakes keeping the button pressed so that you can release it any time you want.

[pacman2881]

Originally Posted by YaeJay

^^ No he was referring to steering becoming suddenly heavy and brake pedal becoming heavy after a couple of applications.
Steering lock happens only if one pulls out the key, well used to like that in almost everything i've driven!

Once I switch off the engine in my Ritz Diesel (but didn't remove the key) and turned the key to ON position (i.e. without cranking the engine). I couldn't steer the vehicle and steering lock indicator glowed. This was done done deliberately by me in a open ground and crawling speeds to check how it worked.

I am not sure if it is specific to Ritz. Is it different in other cars?

[clevermax]

Originally Posted by pacman2881

Once I switch off the engine in my Ritz Diesel (but didn't remove the key) and turned the key to ON position (i.e. without cranking the engine). I couldn't steer the vehicle and steering lock indicator glowed. This was done done deliberately by me in a open ground and crawling speeds to check how it worked.

I am not sure if it is specific to Ritz. Is it different in other cars?

If you had not removed the key (no matter which position it was) and the steering still got locked, it's a fault. Steering should not get locked until the key is removed.

[layndrivr]

thanks for the responses,

got the brakes checked today at the service station and according to the engineers, everything is alright in the car, relevant fluid levels are good and although there is wear and tear on the linings and the pads, but nothing to bring about such an event. i drove it around and it feels alright.

this has left me quite confused, as i would at least like to believe that if not anything else, the brakes are always going to work.

although i should mention, that my car has never been in a major accident, except it was severely rear ended by the maruti service masters themselves in the workshop around 7 months ago. one of the engineers, while reversing the car down from a ramp (wheel alignment i think) instead of pressing the brake, pressed the accelerator and reversed into a wall at 70-80 kmph. they claim that it was only 25-30, but the damage caused was so severe that i cud never buy that story.

they mentioned that the events are not connected as, they had double checked everything.

i'm going to run it for another week and see if anything comes up, i feel like this is not the end of this.

[Ragul]

Originally Posted by Ragul

Your car will have a braking system that depends on the engine being switched on to work effectively. Try this - press the brake pedal then turn on the ignition. You will feel a pressurizing sensation on the brake pedal.

For this reason, your car manual may also tell you never to switch off the engine and coast downhill.

--Ragul

Originally Posted by bluevolt

We are discussing here what do do in case of brake fail and we have quite a few basic steps to follow if such event happens. But the important question is that why brakes actually fails and how to prevent them from failing?

My point was that in the situations where the brakes are weak, switching off the engine will further reduce chances of recovering braking power.

--Ragul

[dhanushs]

Originally Posted by layndrivr

... but the damage caused was so severe that i cud never buy that story.

Well, drum brakes are known to perform poorly while reversing. Try reversing an OMNI in a slope while reversing and at some speed, and you will be surprised (definitely not pleasant) .

[mdsaab]

Originally Posted by dhanushs

Well, drum brakes are known to perform poorly while reversing. Try reversing an OMNI in a slope while reversing and at some speed, and you will be surprised (definitely not pleasant) .

Ah the omni. Forget about the brakes while reversing. They always use to scare me even while going forward. I remember once during the monsoon, our neighbourhood was marginally flooded. Drove through some water. And the brakes vanished. Pumping, standing on them nothing worked. I obviously panicked. But then better sense prevailed and used the box to slow down. Which worked like a charm.

If you have drum brakes please be extra cautious in the wet.
Drive safe!