Hi all,

I have an '03 MCS with 17" wheels. Today I was driving in snow for the first time and on several occasions I had to brake hard and experienced some serious brake weirdness.

After about a second or two with my foot on the brake I could hear and feel the ABS pulsating but the scary part was that I was unable to further depress the pedal. In fact I could feel a STRONG force on the pedal trying to push it back UP.

The first time it happened was in an icy parking lot at about 10 MPH after I'd gone into a skid. Another time was at 55 MPH or so on a wet road that was slightly slushy.

This is my first car with ABS. Is this common with ABS because of snow/ice clogging up the pistons?

 

No, this is your ABS telling you that you're braking too hard. On my 4th car with ABS & they all did it.

 

An aside to my previous post, some years back(10 or 12) when the state troopers got cars with ABS they were crashing them with a MUCH greater frequency than without ABS and they had to learn (go back to school) the ideosyncracies of the beast.

 

A couple of notes:

It's not telling you that you are braking too hard. It is just working correctly. When you feel the ABS, just keep pressing. This is what they are made to do. Regarding the state troopers: the reason that they were crashing was because they were trying to pump the brakes the way they used to before ABS existed. You just need to learn that when it kicks in, it's nothing to fear. It's amazing how well you can control a car using ABS. With good tires, you can actually brake while going into a 90 degree turn on a slick surface and maintain your trajectory.

This is just another commercial for driving school. Everyone MUST go to driving school at least once, just to learn how their car's systems work and how it should be driven!

 

I've never had a car with ABS before, and I actually didn't really like when it kicked in last time I was driving on snow-covered roads. It seemed to activate much sooner and more often than necessary, and it just feels like it's makingthe car do more work unnecessarily. I know ABS is a great safety feature, but I just wish I could switch it off when I feel like sliding around on empty roads!

 

chitown_coop... you are correct, that is how they are supposed to work, but if they start to pulse and you press harder on the brakes they will push back and that tells you ,you are trying to brake too hard so let the abs do its job. And #2 you were correct, that was what the troopers had to learn( not to pump the brakes)

 

I'm not trying to be ornery, I swear! But I'm still a little unclear on what you mean when you say that the ABS is telling you that you're pushing too hard. It doesn't really matter how hard you push, because the ABS is going to pulse at a constant rate regardless. I will still recommend that when they ABS kicks in, you should push just as hard as you want to until the car stops or slows enough. The ABS action will allow you to control the car far better than you would be able to if it weren't there, so why fight it? And Chris, I realize that it seems strange for the ABS to kick in almost constantly in snow or wet, but it only kicks in when the wheels lock up, which they do quite easily in the slick. It's kicking in because if it didn't, there's a good chance that you won't stop or won't be able to control the car to a satisfactory degree.

ABS is good stuff! Enjoy!

 

FWIW... braking distances are actually longer with ABS on snow and gravel than with non-ABS brakes. Locking up the tires creates a "snow plow effect" in front of the tires which helps slow the vehicle, but the ABS computer prevents this.

...just talking about braking distance; car control, steering ability, etc. will be superior with ABS.

 

Please understand this is not condescending or patronizing, just building a base, if your ABS sensors determine that one of your wheels is rotating slower than the others it pulses the pressure to that wheel to prevent it from locking up. if 2 whells have limited traction, it will pulse to both, if 3,etc. Originally from the mountains of PA, I had ample opportunity to experiance (play in) snow. The more wheels that are trying to lock up, the further up the travel the brake pedal will push back and if all four are pulsing the pedal will be practically at the top. Any more pressure on the brake pedal when it is already pulsing (already doing what is supposed to) will not make it stop any faster, just push back harder. So if your brakes are pulsing, let them do their job, and don't try to force them to brake harder by pushing harder. I think I made it too short and sweet by saying "you were trying to brake too hard" An aside.... yes you can lock the wheels on an ABS car, all four wheels must have the same limited traction (ice) and you would have to SLAM the brakes on, then the sensors think you're stopped cause all four wheels stopped at the same time, if only one is a little slower, the ABS will kick in. Try it in a snowy parking lot when no ones around, you don't have to be going fast, 10-15mph is plenty if its icy packed snow. Oh, and you have to be going straight. Just a more thorough explanation of my flippant "trying to brake too hard" You are right, EVERYONE should go to a driver school to learn the capabilities of their vehicle and themselves, a lot of people are out of control at 35mph but in my 59 plus years i've only heard 1 person say "I'm not a very good driver"

 

sonracer using his brakes... Yeh... Right....

 

Interesting points from both dreamin and sonracer. I hadn't even thought about the possibility of the "snowplow" effect. Sonracer, while I agree with your point, I still think that urging people "not to brake hard when the ABS is going" as a general rule will do more harm than good. If it's pulsing, I think the best advice would be to let the ABS do its job--just keep braking like normal, not necessarily harder OR lighter.

 

Exactly

 

Thanks everyone.

Well, I feel like a complete moron. I was under the impression that ABS was always "active" and the pistons were always pulsing - which is why they tell you not to pump your brakes. But from what you guys are saying the system is only activated when your wheels lock up. The fact that the pistons are being "disengaged" would therefore explain the upward pressure I was feeling.

Anyway, as you might guess I certainly didn't expect the sensation to be quite so dramatic! I am a big fan of the snowplow effect when I'm going slow enough, i.e. I'm pulling up to a stoplight in the snow and when all else fails I slam on the brakes, turn the car sideways and let friction take over. Guess I'll have to change my ways. Maybe driving school ain't a bad idea....

Thanks again!

 

Hi Guys,
First off I live in Canada so I deal with snow all the time
But does anyone feel like the abs seems to kick in a little to quick?

Cheers
Vik