Car moving forward when at complete stop on ice and brake applied

[stinger123]

I have had something very unusual that seems to happen intermittently during the winter only- usually once a month or so. It happens under similar circumstances each time when I come to a sliding stop on ice and ABS activates, the car eventually comes to a full stop. After this, about a second or two later, the engine starts revving slightly on its own and the car starts inching/pulling forward even though the brake pedal is still depressed. It is definitely not the car still sliding, as it is after a complete stop and then you can feel the engine pulling the car forward despite brakes on. The car almost feels like it is rocking and will slowly keep moving forward about a foot or two total over 5-10 seconds before it stops. It can be quite scary and I am worried it will pull me into a car in front of me or into moving traffic someday. I plan on taking it in to the dealer but wait times are long and this problem seems very intermittent, so I doubt they will be able to replicate it. Anyone else experiencing this or have any advice as to what could be wrong?

 

[MerlintheMad]

Never heard of this! Have you tried applying the parking brake? It's completely separate from the calipers system.

 

[JSolo]

You could also put it in to N while stopped. Folks with the manual cars get this effect naturally.

I imagine you're pressing the brake harder when the sensation of motion is present after coming to a stop. Even with a little bit of throttle, brakes should hold. How high is it revving?

Does the car stop normally on dry pavement?

 

[stinger123]

Never heard of this! Have you tried applying the parking brake? It's completely separate from the calipers system.

I have never tried applying the parking brake, but will try it next time this happens.

 

[stinger123]

You could also put it in to N while stopped. Folks with the manual cars get this effect naturally.

I imagine you're pressing the brake harder when the sensation of motion is present after coming to a stop. Even with a little bit of throttle, brakes should hold. How high is it revving?

Does the car stop normally on dry pavement?

Not sure of the revs, but it doesn't feel like much. I will make note of that if it happens again.

Yeah, usually when this happens I frantically press on the brake harder while I'm on ice and the car usually starts pulling forward and I'm just trying to steer to avoid any other cars or obstacles. The car has no issues stopping on dry pavement whatsoever, and it happened for the first time this winter today for me. Like I said, it seems to be quite rare. I just went out and did about 20 stops on snow/ice in my neighbourhood and can't replicate it now.

I did have one other odd event last winter when I parked the car on my icy sloped driveway once and left to grab something inside the house (im pretty sure the engine was off and my wife was waiting in the car). When I got back to the car she said it started sliding backwards a foot or two down the driveway before stopping and was worried it would slide onto the road.

Very odd.

 

[JSolo]

We have a slightly sloped driveway. Any time the car is parked (even inside the garage), I always set the parking brake. Decades of driving manual cars will do that.

Keep good following distance when coming to a stop...

 

[JimB47]

Just an odd suggestion, I don't suppose the warmth in the tyres together with the cars weight is melting some of the ice and the car moves on the water, a bit like we skate on ice

 

[Kamauxx]

I have had something very unusual that seems to happen intermittently during the winter only- usually once a month or so. It happens under similar circumstances each time when I come to a sliding stop on ice and ABS activates, the car eventually comes to a full stop. After this, about a second or two later, the engine starts revving slightly on its own and the car starts inching/pulling forward even though the brake pedal is still depressed. It is definitely not the car still sliding, as it is after a complete stop and then you can feel the engine pulling the car forward despite brakes on. The car almost feels like it is rocking and will slowly keep moving forward about a foot or two total over 5-10 seconds before it stops. It can be quite scary and I am worried it will pull me into a car in front of me or into moving traffic someday. I plan on taking it in to the dealer but wait times are long and this problem seems very intermittent, so I doubt they will be able to replicate it. Anyone else experiencing this or have any advice as to what could be wrong?

Your car is either sliding on ice or your brakes are completely trashed and not fit for a bicycle.

Brakes don't just stop working anytime there is snow/ice on the ground. If the brakes were shot they'd also fail when it is dry/warm out.

You car is sliding on ice.

 

[D.J.]

I did have one other odd event last winter when I parked the car on my icy sloped driveway once and left to grab something inside the house (im pretty sure the engine was off and my wife was waiting in the car). When I got back to the car she said it started sliding backwards a foot or two down the driveway before stopping and was worried it would slide onto the road.

Very odd.

Was it like this (hope these vids work)

If you did not use the parking brake, and you have a model with an open diff, this can easily occur if only 1 wheel looses traction.
Parking brake would lock both rear wheels, Parking pin requires both rear wheels to have traction in order to work.

Video from the internet

2 new videos · Wednesday, Mar 13, 2019 🎬

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Google Photos

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Google Photos

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[stinger123]

Was it like this (hope these vids work)

If you did not use the parking brake, and you have a model with an open diff, this can easily occur if only 1 wheel looses traction.
Parking brake would lock both rear wheels, Parking pin requires both rear wheels to have traction in order to work.

Video from the internet

2 new videos · Wednesday, Mar 13, 2019 🎬

Tap to view!

redirect.viglink.com

Google Photos

photos.google.com

Google Photos

photos.google.com

Those videos seem to be very similar to what happens in my first post description after stopping on ice sometimes. The car pulls forward like that after stopping, maybe not as aggressively as in that video but that is pretty much it. I have the Canadian 2018 Stinger GT AWD (I am not sure about differential). What does this mean?

 

[ThunderBoy724]

I have also experienced this. Last year a few times before I figured out what the problem was and once this year because I forgot.

When the road is icy or even hard packed snow there is limited traction. If you apply the brakes gently the fronts will hold much stronger than the rears. The car is a rear wheel drive bias so it is sending more power to the rear wheels and the engine can over power a light application of the brakes on a slippery surface. I have had it happen several times before I figured out what was happening. If you press harder on the brake pedal when stopped it will lock the rear wheels.

I was able to figure this out from old school experience. Cars with carburetors in cold weather with the choke on are raving faster at idle. Older cars commonly had rear drum brakes that were weaker than front discs and were more commonly rear wheel drive. The car would be revving at a stop and the rear wheels would be spinning. A car with an open diff would start to slide sideways in the rear just like my Stinger GT with an open diff. After this happens a few times I start to think "Hey that's just like the cars in the old days" and then it clicks that the rear wheels are turning on the slippery road. So the next time it happens I press a little harder on the brake and presto! it stops.

As for the engine revs increasing the most likely culprit is your right foot is just slightly contacting the gas pedal especially if you have large feet. When the car starts unexpectedly moving forward you instinctively press harder on the brake but also press harder on the gas until you adjust your foot on the pedal.

My advice to anyone is to pay close attention to exactly what you are doing when this happens. Ask yourself is my foot on the gas? Am I pressing the brake hard enough when stopped?

 

[stinger123]

I have also experienced this. Last year a few times before I figured out what the problem was and once this year because I forgot.

When the road is icy or even hard packed snow there is limited traction. If you apply the brakes gently the fronts will hold much stronger than the rears. The car is a rear wheel drive bias so it is sending more power to the rear wheels and the engine can over power a light application of the brakes on a slippery surface. I have had it happen several times before I figured out what was happening. If you press harder on the brake pedal when stopped it will lock the rear wheels.

I was able to figure this out from old school experience. Cars with carburetors in cold weather with the choke on are raving faster at idle. Older cars commonly had rear drum brakes that were weaker than front discs and were more commonly rear wheel drive. The car would be revving at a stop and the rear wheels would be spinning. A car with an open diff would start to slide sideways in the rear just like my Stinger GT with an open diff. After this happens a few times I start to think "Hey that's just like the cars in the old days" and then it clicks that the rear wheels are turning on the slippery road. So the next time it happens I press a little harder on the brake and presto! it stops.

As for the engine revs increasing the most likely culprit is your right foot is just slightly contacting the gas pedal especially if you have large feet. When the car starts unexpectedly moving forward you instinctively press harder on the brake but also press harder on the gas until you adjust your foot on the pedal.

My advice to anyone is to pay close attention to exactly what you are doing when this happens. Ask yourself is my foot on the gas? Am I pressing the brake hard enough when stopped?

This sounds like what I am experiencing. It feels like the brake is working on some tires, but others want to keep the car moving. Like I said before, I usually start panicking when this happens, so next time will pay closer attention to how hard I am applying the brake.

 

[D.J.]

Those videos seem to be very similar to what happens in my first post description after stopping on ice sometimes. The car pulls forward like that after stopping, maybe not as aggressively as in that video but that is pretty much it. I have the Canadian 2018 Stinger GT AWD (I am not sure about differential). What does this mean?

Your car, like mine, has open diffs both front and back. (2018 Canadian AWD).
We do not have an LSD front or rear.
If you park without the parking brake, either rear wheel on ice can cause the condition in the videos in post #9.

As for your engine RPM's increasing - I too suspect you may have inadvertently pressed a little bit of throttle, while breaking.

 

[nhcowboy28]

 

[JSolo]

Christine!

Just in time for movie night tonight.

 

[rpoffen]

I doubt the engine is overpowering the brakes. When I race at the track, I hold the brake at the line and rev up to 2800 RPM and about 6 lbs of boost to launch and the brakes hold firm until I release the brakes. The brakes hold quite well.

 

[D.J.]

I doubt the engine is overpowering the brakes. When I race at the track, I hold the brake at the line and rev up to 2800 RPM and about 6 lbs of boost to launch and the brakes hold firm until I release the brakes. The brakes hold quite well.

Difference being, it's not overpowering the brakes...

It's overpowering the available traction of the front wheels on ice.

With gentle brake pressure, enough to lock the front wheels on ice while stopped, the rear brakes can easily be overpowered with a tap of the gas.

 

[n8hegr8]

Never heard of this! Have you tried applying the parking brake? It's completely separate from the calipers system.

dumb question here, if you needed to use the emergency brake for emergency braking in the moment in a stinger, does it work the same way as old cars that had the big handle you pull if you needed emergency braking, but you just pull or push the little grabby handle thing a ma jig? never read about it in the manual.

 

[D.J.]

from

dumb question here, if you needed to use the emergency brake for emergency braking in the moment in a stinger, does it work the same way as old cars that had the big handle you pull if you needed emergency braking, but you just pull or push the little grabby handle thing a ma jig? never read about it in the manual.

if you are driving at 100 km/hr, and you pull the EPB switch - the actual brakes will apply (hydraulic), unless there is a severe malfunction.
The brakes apply smoothly and increasingly, and will bring you too complete stop. The parking brakes are probably also applied.

Basically, if you are driving and your passenger pulls the EPB - you will be stopping promptly, using the same brakes the car uses for adaptive cruise control (main hydraulic brakes) - if your vehicle is equipped with the EPB



From my manual

 

[n8hegr8]

holy balls, imagine going 100 and then having to use that. your organs would surely come out of your body.