Grabby Brakes?

[MichaelS]

I have never experienced the brake grabbing at slow stop and go speeds. But I did have the brakes come on after I tapped my brakes three times to try to get some tail gating gas hole off my butt. After the third tap the brakes didn't release until a second or so after I released the pedal.

Scared the hell out of me. I have yet to test it again after the software update.

Michael

 

[keydiver]

My 2012 has this issue also, 4-5 times in 2 1/2 months. It happens so randomly that I haven't been able to deduce exactly what conditions cause it. But, I *think* it is usually at low speed, like <40 mph. The strange thing is that the next time you tap them, the brakes are completely normal.

 

[garygid]

So, does the current firmware change the braking behavior at all?

 

[OrientExpress]

So, does the current firmware change the braking behavior at all?

Yes, it seems to have cured the grabby brakes.

 

[TomT]

I'd question that... Mine is getting done the end of next week and I'll report my observations then, but a co-worker has already had his done and there was no change in the brake crab behavior for him.

So, does the current firmware change the braking behavior at all?

Yes, it seems to have cured the grabby brakes.

 

[Wattson]

So, does the current firmware change the braking behavior at all?

It seemed to make mine completely normal.
But anyone who hasn't tried switching off traction control for a few miles of city driving should do so and report back- it helped a lot with my car before the software upgrade.

 

[derekjsmith]

No I had ours updated two weeks ago and have the same issue with the brakes. As I think many have pointed out it has to do with the brake assist and anti-lock.

My background is a professional driver, high performance driving instructor on and off the track for some 25+ years Proformace Racing School. So my braking method is different than the average driver. For on track you go to the brakes quickly, firmly, then release as needed but never fully release until you are done with very little modulation. Using this method on the Leaf will case the brake assist to over boost if you try to modulate before a full release. The only way I have found to get it to reset is to fully release the brakes for a couple of seconds.

I think what is happening is the brake assist sees I went to the brake quickly and firmly but did not activate the ABS so that sets up the first condition, did I intend to activate the ABS or not. Then if I modulate the brakes again not activating the ABS and not fully releasing the brake assist thinks yes I did really mean to get into the ABS and it goes into over boost mode. The braking system thinks it knows better and I really needed or meant to activate the ABS in a panic stop so it will over boost to get the car stopped even without getting into the ABS.

I have to adjust my driving style a bit when driving the Leaf. I find that if I don’t get into the brakes quickly kind of drive the car lazily it does not happen.

 

[TRONZ]

Had the 1 year done last week but they could not do the software update because "the manuals were backordered". Um... OK. Mentioned the low speed grab so they took a look. Offered to do a full brake fluid flush if I wanted ($$??... well, whatever!). Seems to have firmed the feel of the brakes a tiny bit (easier to modulate) and this may help a tiny bit. But it just does not feel smooth. Still a grab just as you come to a full stop.

My gut tells me its an issue with the brake pad composition/seating of the rotors since mine started at about 7k miles. I have had sportbikes that mutated like this after pads/rotors got fully seated. The first person to get new pads and rotors turned will be able to say.

 

[SDLeaf]

I had the software update, and no, it didn't fix the problem.

After talking to Nissan and asking them to file a report/case, someone corporate (I suspect) called on a weekend and was very nice and said that their engineers have been able to replicate the issue but at this time, they feel it's "a normal characteristic of the Nissan Leaf vehicle." But since for me, the issue seemed to come up after a few thousand miles of driving (about 5 months or so) that they recommended I have the dealer look at it.

The tech at the dealer went on a test drive with me (he drove) and I explained what happens and when, and he was also able to note and make it happen. They hooked it up to the computer and the car's computer wasn't kicking out any error codes and reported everything was fine. But he said that in the next day (today actually) that a Nissan engineer was going to be there and I could leave the car and have them check it out.

Well, the engineer guy canceled and didn't show up, so they just called Nissan Tech and they said exactly what others have reported ... basically that the car is fine, and that's the way they drive with the regenerative breaking.

I'll try the traction control thing and some of the other tricks noted here. But I guess my thing is that they can't possibly expect that people will be happy with a $34k car that lurches to a stop. Hell, you can by a $15k car that has better braking control.

I get the impression these are the curses of a new model car and that Nissan just doesn't want to admit that there is some kind of problem with the braking system that is triggered by a series of events (since not everyone has the issue). My buddy also has a Leaf, and he's never experienced the issue in his Leaf.

 

[TomT]

Mine has now been done and I notice absolutely no difference in the grabby brake behavior... That is to say, it is every bit as bad as it always has been...

I'd question that... Mine is getting done the end of next week and I'll report my observations then, but a co-worker has already had his done and there was no change in the brake crab behavior for him.

So, does the current firmware change the braking behavior at all?

Yes, it seems to have cured the grabby brakes.

 

[FairwoodRed]

I've been trying out the suggestion on the traction control. No dice for me. I have grabby brakes before, during, and after.

I am actually encouraged by Nissan corporate acknowledging the symptoms. That means that they might have someone in the background working on an improvement. Given Nissan's prior response with the AC trouble last year, I wouldn't be surprised if they keep mum until they have something positive to say.

 

[poolrider]

I can rarely get my Leaf come to a smooth stop without it jerking to a stop. The brakes are weird and inconsistent. I've never in all my driving years experienced anything this annoying with car brakes. I've had this problem for months and have taken it in to the dealership twice. Both times they told me that there was nothing wrong. But there clearly is. I had the firmware update, which some say that it solved their problem, and it made no difference.

I think that enough people are complaining about "grabby brakes" that now Nissan's engineers have come up with an explanation, which if I understand correctly, goes something like this: if you put pressure on the brakes more than once without stopping or pressing on the accelerator, the car will interpret that as an emergency stop and bring the car to a sudden stop. In addition, they said that it was a "world car" and as such, had to conform to European standards, which apparently require jerky brakes?

First of all, my car shouldn't tell me that I'm coming to an emergency stop if I press on my brakes more than once to stop. If I want to emergency stop, I'll slam on the brakes. Secondly, I've driven cars in Europe and have never experienced anything like this. So this sounds like B.S. And finally, this condition makes for very uncomfortable driving and could in some cases be unsafe.

Has anyone experienced this problem and figured out a way to resolve it? Seems like Nissan is in denial mode.

 

[GeekEV]

First of all, my car shouldn't tell me that I'm coming to an emergency stop if I press on my brakes more than once to stop.

But that's not quite it either. People are speculating that it might have something to do with that, but I've been paying careful attention and it's very much a "sometimes it does, sometimes it doesn't" situation.

 

[TomT]

Exactly. It is very unpredictable and certainly appears to be a software and/or hardware anomaly...

But that's not quite it either. People are speculating that it might have something to do with that, but I've been paying careful attention and it's very much a "sometimes it does, sometimes it doesn't" situation.

 

[davewill]

The best explanation I've seen was Ingineer's. He claims that after you've had your foot on the brake for a certain period of time, the car shuts down the "creep" torque. Apparently it's hard on the drive system to stay in creep mode too long. This causes the "grabby" feel of the brakes.

 

[GeekEV]

The best explanation I've seen was Ingineer's. He claims that after you've had your foot on the brake for a certain period of time, the car shuts down the "creep" torque. Apparently it's hard on the drive system to stay in creep mode too long. This causes the "grabby" feel of the brakes.

I'm still not sure about that. I've seen it happen also while decelerating from speed to a stop. It's fine and then when I go to apply that last little bit of pressure to actually stop the car it jerks. I suppose that could still be creep torque, but I swear I've seen it happen even without holding the brake first...

 

[johnr]

I get the impression these are the curses of a new model car and that Nissan just doesn't want to admit that there is some kind of problem with the braking system that is triggered by a series of events (since not everyone has the issue). My buddy also has a Leaf, and he's never experienced the issue in his Leaf.

I suspect you're right. And the way Nissan prefers to deny the problem than to try and fix it is one thing that has made my opinion of Nissan as a company really plummet. The Leaf is a great car because it's electric, but my next electric car certainly won't be a Nissan.

 

[garygid]

My braking from speed (fast or slow), is usually gentle,
and seems perfectly smooth.

What am I doing "wrong" to not experience this problem?

Occasionally, I will have a "grab" when first backing out of the garage.

 

[gbarry42]

What am I doing "wrong" to not experience this problem?

Didn't you know? It never happens when you're thinking about it

As to Ingineer's remark, if this were true, the "grab" should happen without any change in pedal pressure, during a long stop. And it doesn't. Also, he put forth that theory last October, and may not have ever experienced it at that time. He may have some later thoughts about that.

 

[derekjsmith]

The best explanation I've seen was Ingineer's. He claims that after you've had your foot on the brake for a certain period of time, the car shuts down the "creep" torque. Apparently it's hard on the drive system to stay in creep mode too long. This causes the "grabby" feel of the brakes.

Still happens if the car is in neutral with or without traction control. Which should negate regeneration, creep torque and dynamic braking. It has to do with predictive braking algorithms getting it wrong.