Paceship

why would left rear tire continue turning in snow or soft sand when braking? Infiniti say's it's the ABS "catching up". But, if this is normal, it's dangerous. I was going down a slopped snowy driveway and although fully braked, the left rear time kept turning under power. Any ideas...PLEASE.

blackfunk

iTrader: (1)

Not following here at all. How did you know the left rear tire kept turning? And if you're braking then where's the power coming from? Infiniti's have a brake override system that prevents power going to the wheels when braking ala last gen Toyota's.
How do you know it wasn't just a loss of grip?

Paceship

Thanks for replying. The left rear tire is still powered...as odd as that sounds. I've looked out my window while braking and watch the tire turning and digging in and compacting the snow to a slick ice. Last summer I watched the tire dig a hole on a dirt road. Infiniti said this was a normal condition due to the ABS "catching up" (whatever that means). But, the ABS system had not triggered, so I'm totally baffled.

dkmura

ABS will allow wheels to continue turning even as it pulses the brake engagement. If a wheel or tire locks up, it could cause the G to slide sideways. What you're seeing as you look out the window (into a reflection?) is the wheel and tire attempting to brake on snow while on the edge of locking up. It's not having any power applied to it, despite what you suspect.

mtech369

this is normal operation. nissan's vdc sys like many other systems from other manufacturers such as mercedes benz esp is designed to allow at least one wheel to have power which in turn provides traction to help eliminate the chance of skidding.

monty2003

Still not sure I understand the situation. Is the car stationary and 3 out of 4 wheels not rotating when the left rear continues to rotate?

If that's the case, check your brakes on that wheel. Could be that brakes on that wheel are not engaging. On a very slippery surface like ice even idle torque can cause a wheel to slip when there are no brakes.

Brian

Paceship

Yes, all other tires are stopped...just the left rear keeps turning. And I just had the rear brakes done, so I know they're all working properly. Weird, huh? To be clear, it only happens while going down an snowy driveway or after backing up then going forward up a slightly inclined sand base road. The wheel DEFINATELY is under power, not just freewheeling as evidenced by the compacted snow, or hole dug in sand. Just a thought, if helpful, this only happens soon after starting the car, and never on pavement.

monty2003

Sounds still sounds like a brake issue.... you are pushing the brakes when this happens right?

If you have your foot on the brake pedal, the car is stationary, and one wheel is spinning then the brakes are not engaged on that wheel.

The fact that it occurs after you start the car makes sense because it idles faster until it warms up a bit.

The fact that you had the brakes serviced doesn't guarantee the brakes are working - could need a bleed, pads contaminated, pad's bound up, etc.....



Question - when this condition occurs, is the ABS system going off?


If you are not pushing the brakes and the wheel is spinning then it sounds like you have an ABS sensor issue.

Brian

mtech369

its normal operation of the vdc sys. by providing power to at least one wheel the car can have traction and eliminate the chance of skidding.

Paceship

Monty... Thanks a lot for your response. Yes, I am pressing hard on the brakes, and the ABS system is NOT engaging. I will look into checking to see if that one wheel's brakes are engaging or not. Just curious, is there a way to tell if that brake is working without taking it to a service center and putting it on a lift to check?
Thanks again

Paceship

MTECH.. thanks to you for your reply. My question regarding the vdc system is why wouldn't the applied brakes stop ALL four wheels. That is, why does that one rear keep turning under power?

mtech369

vdc is computer controlled software tied into conventional brakes, abs, tcs, stability program, and engine throttle. when u apply your brakes at normal situations such as dry pavement on flat land all 4 brakes get applied. abs sys is monitoring wheel speed sensor and only gets activated when abs module sees impending wheel lock up. it then dumps brake pressure to alleviate applied brakes. traction control works in conjuction with abs sys where when it see excessive wheel speed it applies the brakes for the spinning wheel to regain traction.

the whole purpose of not engaging all 4 brakes calipers on the vehicle is to "prevent skidding". especially under the conditions u stated, "going down snowy driveway" and "slightly inclined sand base road"

when you skid u lose not only traction but you have lost stability. and the vdc is allowing one of your wheels to be under power so vehicle "does not" lose traction.

this is not a conventional brake issue nor is it any type of abnormality of abs. remember abs will never lock up brakes, it is not designed for that purpose. abs acronym stands for "anti-lock brake system" hint "anti"