Brake Pedal Sinks Under Deceleration At High Speed In Curves

[ALEX-EASTERN-EUROPE]

Hey guys,

Just joined this great forum, and would like to ask a question about the brakes on my 2007 Avensis 2,0 d4d.

When I step on the brake pedal while driving at relatively high speed (doing over 60 mph) AND I turn the steering wheel in order to turn left or right, the brake pedal SINKS (!!!), there's a shrieking sound from under the car and the effectiveness of the car's brakes drops, and the anti-skid light flashes on the instrument panel, while producing a beeping sound.

As I step on the brake pedal again, everything comes back to normal again.

The Brake Pedal also sinks into the floor while producing that shrieking sound when I step on it while trying to brake on bad portion of road.

This is of course quite alarming as it happens when I drive relatively fast AND I am entering a curve, so I do NEED good brakes...

I would like to point out the fact that none of this stuff happens at low speeds and on smooth roads, where the brakes work just fine.

Could you please give me ideas as to what could be wrong with my breaking system?

Thank you very much!

[Devon Aygo]

If the ABS / VSC light is flashing and beeping the car is warning you that you are driving the car in such a way as to activate the vehicle stability control system and the car is responding to a situation where it is detecting a loss of vehicle control by applying the brake to individual wheels ( making the pedal drop, a loud noise from the ABS pump as it works the brakes ) in an attempt to bring the vehicle under control again.

Try taking the same corners again at a speed not requiring you to brake, if the car goes round he corner without issue then you where going too fast!

One point to make if you should find yourself in a similar situation NEVER release the brake pedal until it is safe to do so keep your foot down and let the cars VSC/ABS correct the loss of control only then do you let the pedal go, releasing the pedal could result in a further and more severe loss of control.

[Druid Boy]

As above, you are overloading the tyres, they are losing grip and the car is taking control of the situation for you by adjusting your braking. For cornering, as the old saying goes 'Slow in, fast out. Fast in, s**t out'.

Slow down a bit eh?

[ALEX-EASTERN-EUROPE]

Thank you for your replies!!!

It never crossed my mind that I was going too fast into the curves, although I'll admit the fact that I was exceeding the speed limits shown on the road signs installed just before the curves ...It felt perfectly safe to me. I guess I was wrong, which is good news, because that means the car's fine.

Forgot to ask, if on a dry road I always turn the TRC off, how come the car still takes control for me unde those situations???

P.S. It's a great forum.

[Cyker]

I clearly need to put you in my Yaris for a few days, that'd calm you down by scaring the **** out of you when you tried that on a corner Body roll and understeeeeeeeeeer!

But yeah, the anti-skid light should be a big clue you are going too fast!

You could make it better by getting stickier tyres, but I would lean more toward the slowing down option personally !

[Whitewagon]

The safe way is never brake whilst cornering, it makes the car unstable and you are likely to lose control. Weigh up the corner as you approach and reduce your speed to one where you are able to negotiate it without needing to use the brakes. Using very light throttle, just enough to maintain the drive, will give you more stability, don't start to accelerate until you are almost out of the corner.

[Cyker]

Well it's a bit trickier than that if you're that close to the limits of grip - For instance, if you are braking while going round a corner and lift off suddenly, the weight transfer will flick back, unloading the front tyres increase the chance of understeer. Lifting off smoothy is the key.

As you say tho, it's best to get the slowing down and braking out the way BEFORE you start turning into the corner.

I've been finding I have to negotiate corners a lot more slowly on my current set of tyres (Cooper CS2's - Great wet braking and aquaplaning resistance in a straight line but have absolutely terrible lateral grip in the wet and the dry! Would not buy again...)

[Konrad C]

Thank you for your replies!!!

It never crossed my mind that I was going too fast into the curves, although I'll admit the fact that I was exceeding the speed limits shown on the road signs installed just before the curves ...It felt perfectly safe to me. I guess I was wrong, which is good news, because that means the car's fine.

Forgot to ask, if on a dry road I always turn the TRC off, how come the car still takes control for me unde those situations???

P.S. It's a great forum.

A lot of cars have an ESP switch, but some manufacturers have an override to retake control.

Watch 5th Gear or Top Gear and even the fast exotics have this system, where the traction control cuts back in or not fully turned off.

This protects you and other people on the public road, and the maker of the car.

[ALEX-EASTERN-EUROPE]

Thank you guys for all the feedback, it's been really helpful!

I clearly need to put you in my Yaris for a few days, that'd calm you down by scaring the **** out of you when you tried that on a corner Body roll and understeeeeeeeeeer!

But yeah, the anti-skid light should be a big clue you are going too fast!

You could make it better by getting stickier tyres, but I would lean more toward the slowing down option personally !

Nice post!!! But I think I would rather drive a junior sports car like a Celica, MX5, RX7, than a Yaris, :)

The Yaris simply discourages you to drive fast, while my Avensis does encourage sporty driving (it's got a bit of poke - 310 NM of torque) and it loves fast driving - 120 - 130 mph.

However, when I am really starting to push it, it tells me I might be driving the wrong car... it's a teaser the Avensis ;-)

Anyway, here my Avensis for those who are curious to see it. Personally I like it very much.

[Devon Aygo]

Thank you for your replies!!!

It never crossed my mind that I was going too fast into the curves, although I'll admit the fact that I was exceeding the speed limits shown on the road signs installed just before the curves ...It felt perfectly safe to me. I guess I was wrong, which is good news, because that means the car's fine.

Forgot to ask, if on a dry road I always turn the TRC off, how come the car still takes control for me unde those situations???

P.S. It's a great forum.

TRC is traction control, it stops you from spinning the wheels under heavy acceleration, this can cause issues in slippery/icy/snowy conditions where you actually need to spin your wheels TRC would stop you, so Toyota allow you to switch it off.

VSC is stability control to help you control the car should you push the car beyond the limits of it handling capabilities. Toyota do not let you switch this off in an Avensis. GT86 they do!