Grabby Brakes?

[rmakela]

I saw this topic mentioned a few months back - but no real resolution. I have about 3000 miles on my Leaf. I've recently started experiencing a grabbing of the brakes/regen, especially when I'm going down a long hill or coming to a rolling stop. It's really inconsistent and makes it impossible to come to a smooth stop. I thought it was just me, but it seems to have gotten worse. It happens whether I am charged to 80 or 100%. Anyone else experienced this condition? I'm not willing to let this one go as a "feature" of regen - it seems borderline safety issue to me, especially when you stop much quicker than expected with traffic behind you. Any ideas?

Ray

 

[lincomatic]

If it happens w/ 100% SOC, then it's not a regen issue. And if it shows up after 3000 miles, then something has changed. Take it in to the dealer and have them check it out.

 

[cdrews]

I was just thinking about posting exactly the same thing . I have the exact same problem.

Has anyone brought their leaf back to the dealer to examine the problem?

-= Clemens

 

[abasile]

I've experienced the same thing occasionally. The brakes act more grabby than usual. However, I'm not going to bother taking the car to the dealership for what is at worst a minor annoyance. I've never thought of this as a safety issue because I've found it easy to respond by reducing pressure on the brake pedal.

 

[mwalsh]

I've never thought of this as a safety issue because I've found it easy to respond by reducing pressure on the brake pedal.

Except in some instances that doesn't work. The specific one I'm thinking of....you're sitting stopped in stop-and-go traffic when the cars in front of you start to inch forward. So you let up off the brake pedal, allowing your car to creep forward. But then the traffic ahead stops again, so you need to reapply your brakes. Sometimes when you do this the brakes grab with inappropriate force, causing the car to come to a very sudden stop, even with very minor force on the brake pedal.

 

[TomT]

I've experienced the same phenomena on occasion and have learned to live with it... It seems like a bug in the Brake Assist algorithm to me...

I've experienced the same thing occasionally. The brakes act more grabby than usual. However, I'm not going to bother taking the car to the dealership for what is at worst a minor annoyance. I've never thought of this as a safety issue because I've found it easy to respond by reducing pressure on the brake pedal.

 

[davewill]

Yeah, it happens on occasion when I'm stopped, or nearly stopped, and trying roll forward slowly. You can't apply pressure lightly enough to do anything but lurch to a stop. The only way to clear the problem is to release the brake completely. It's been an annoyance, but not a big enough one to complain about.

 

[DarkStar]

I always thought this occurred because the pump hasn't recovered its pressure yet. Either way, this happens to me too, only at very low speeds, while creeping. Same as davewill.

 

[Christopher]

I've actually experienced the opposite effect. On several different occasions at low speeds, many weeks apart, I've been surprised to suddenly find the brakes not responding normally and I'll need to press much harder to get the intended effect. It's very disconcerting. I can still stop but it takes much more effort and it's very hard to brake smoothly. And then a few minutes later, things are back to normal. (And no, it's not wet conditions.)

Now that I think about it, perhaps this is the same effect others are describing as very grabby. They're certainly very grabby when I push harder to compensate -- it's just that I first notice how they don't respond properly with normal pressure on the pedal.

There's no common situation this happens other than I think it's only ever happened soon after starting the car from being parked somewhere briefly -- never while I've been driving a while or parked for a long while.

 

[FairwoodRed]

Wow. Talk about great timing. I signed in this morning (after a few weeks off) just to research this problem. I've got 5500 miles on and I fight the grabby breaks a lot now. Particularly in slow rolling freeway traffic. It's getting to the point that I am worrying about getting rear ended. I plan to bring it up at my service visit in 2 months, or sooner if I find myself at the dealer. Thanks for bringing it up Christopher!

 

[hpage]

I have about 600 miles on mine and yes indeed, about 5% of the time when applying the brakes while driving very slowly, I experience grabby brakes..

Note that it is possible to experience similar (the same?) by placing the "gear" shift selector into N-neutral position and applying the brakes (i.e. without regen)..

 

[garygid]

Does this very-low-speed "grab" occur in both D and ECO modes?

My LEAF's brakes always seem very smooth, but I am always in D mode.

Maybe if one is rolling slowly enough, the wheel-rotation sensor's "impulse" is too infrequent for the firmware, and the skid-detector gets activated, causing something like the ABS to pulse (grab) the brakes.

 

[TomT]

I am almost always in ECO so my experiences with this abnormality have been in that mode and I can't comment one way or the other if it also occurs in D.

Does this very-low-speed "grab" occur in both D and ECO modes?

 

[Herm]

Apparently all regen brakes have a weird non-linear feel at some point.. anyone notice rust on the rotors?

 

[abasile]

At least once, this grabby behavior happened to me while going at least 15 mph on a steep downhill, when the car was (according to the Energy Info screen) blending in at least some regen braking. I gently increased pressure on the brakes in preparation to descend a hairpin turn, and unexpectedly ended up giving my passengers a bit of a jerk. This never seems to happen if I keep the SOC low enough before making that particular descent (Kuffel Canyon down to Lake Arrowhead) and am careful to do more regenerative braking. I always use either ECO or N (for coasting).

 

[johnr]

I've experienced this phenomenon as well, but was unable to reproduce it at the dealer. Now I'm starting to understand when this happens, as it has happened several times since then - so I might just bring it in again and show them, when I'm confident I can reproduce the issue.

 

[DeaneG]

Happens to me sometimes in D at parking lot speeds. Very noticeable and a little annoying.

 

[SanDust]

8000 miles and never noticed anything but perfect behavior. Surprisingly normal actually. However I don't drive in ECO. That could be one difference.

 

[GeekEV]

Me too. Mostly at parking lot speeds, like others have observed. I've never considered it a safety issue, but it does make for some embarrassing driving sometimes.

 

[TEG]

Related older thread:
http://www.mynissanleaf.com/viewtopic.php?f=8&t=1857" onclick="window.open(this.href);return false;