Driving in B mode often can cause issues?

[MervinsOnlineID]

I wanted to quickly share this in case someone is going through the same issue. I started leasing the e-Golf in the beginning of the year. It’s perfect for me. Work is about 15 miles away and we have free charging at work.

6 months later, I started noticing a screeching noise when I accelerate from a stop. The noise usually fades away once I go above 10mph.
I brought the car to service. Since the noise didn’t happen frequently, I decided to bring them video proof. Unfortunately, they were not able to replicate the issue.

Fast forward 2 months. The noise started to become more frequent and even louder. I went to VW service again and insisted to test drive the car with a technician. This time, I was able to replicate it with them present.

The technician knew what it immediately. The culprit was a GLAZED ROTOR. They cleaned up both rotors and break pads. Havent heard the noise since.

This is only after 6 months of normal stop and go driving (Los Angeles traffic). I do have a couple of hills on my way to work. I love to drive in B mode when going downhill. Do you think driving in B mode often caused this issue?

Video: The sound that I'm talking about
https://www.dropbox.com/s/y4oeq1qiu96znrm/File%20Aug%2021%2C%203%2018%2016%20PM.mov?dl=0

 

[johnnylingo]

Glazed rotor is a build-up of brake dust that causes a squeaking sound when the car is coming to a halt. 'B' mode activates full regenerative braking. My understanding is regenerative braking does not involve the brake pads or rotors at all. So don't see how they could be related. If anything, driving in B mode should prevent glazed rotor.

 

[MervinsOnlineID]

^^^ Tha's what I thought. But i guess if you don't use the foot brake often, dust will just stay there and bake. The technician told me that this happens a lot with hybrid/electric cars because you tend to rely on engine braking more than foot brakes.

He suggested to once in a while, put the car on neutral and do a hard brake (at a safe location of course) to remove the build up on the rotors.

 

[f1geek]

I have been driving in B mode about 95% of the time for the past 2.5 years and about 20,000 miles. I hear some squeaking every morning when I back out of my driveway (sloped downhill very slightly), but it is very minor. Once I drive forward, there is complete silence. Occasionally at the end of the work day, I hear a very slight squeak the first time I brake before leaving the work parking lot, and then complete silence from the brakes all the way home. I have a tough time believing B mode is at fault.

 

[RonDawg]

^^^ Tha's what I thought. But i guess if you don't use the foot brake often, dust will just stay there and bake. The technician told me that this happens a lot with hybrid/electric cars because you tend to rely on engine braking more than foot brakes.

I leased a Leaf for 3 years and put just under 27k miles when I gave it back. I've had my eGolf over 2 years and have just under 15k miles on it. I've never experienced such a thing.

 

[NeilBlanchard]

Using B means you use the friction brakes LESS, so the glazing must have been because a rotor was stuck, or something like that.

 

[forbin404]

Did they fix it under warranty?

 

[whyeGolf]

After working on brake calipers and rotors for years - I would say it has very little to do with driving in "B" mode.
Glaze on rotors can be several things: Stuck Caliper where the pins that the caliper slides on are not lubricated and free. Cheap rotors and metallic pads polishing the rotors. I guess if the vehicle sits parked and the rotors rust then the pads would polish down the rotors using the rusted steel.

By design, the Pads physically touch the rotors all the time. Using Regen 1,2,3 or B has nothing to do with press the brake or increasing Pad pressure against the rotors.

Many questions to fill in: How many miles since the rotors were installed or turned? Was the pads replaced at the same time? Where all the parts "Official VW parts" or cheap after market? Were the brake calipers serviced / cleaned / lubricated regularly? Have you ever ever had to stop very hard - maybe slam on the brakes to avoid an accident - possible warping or over heating the rotors? Who services the vehicle ? Was only one rotor glazed or all of them? I even had a service tech forget to put in the caliper pins and gave my wife the car keys. It seized on the freeway - fortunately no one got hurt.

For example: The brakes on my Prius (sold it) lasted 90k and I used the "B" mode all the time on hills. BMW, Volvo, etc. go through brakes much faster than other cars. I got 30k out a set on the BMW. Some very cheap after market rotors glaze faster and last a shorter time period.

 

[MervinsOnlineID]

Did they fix it under warranty?

Yes they fixed it under warranty.

@whyeGolf
I just started leasing the car January 2017. This was basically the first time VW serviced the car. The technician cleaned both the rotors and the pads.

I dont remember ever slamming on the breaks that hard. My daily route to work is mostly back roads. I try to avoid highways because of the traffic. It's been a week since they cleaned it and I havent heard any sound. Hopefully it never comes back!

 

[treitenbach]

Thank you for posting the video as it enabled me to confirm we have the exact same sound. We drive almost exclusively in B mode in stop-and-go traffic where one pedal driving is a gift. The brakes are used very little and the explanation of a little rust or dust on the pads and rotors made sense.

I took a 10 minute spin with lots of brake applications and the low speed squeaking (identical to the video at the start of this thread) is gone.

I would like to add this is after a dealer visit where they replaced the bearings, strut mounts and had to realign. All thankfully under warranty.

 

[zanzabar]

I am suspicious of the diagnosis from the dealer. "Glazed" is a specific term, and I would bet yours just were rusty or perhaps the caliper was a little stuck and it caused some buildup on the inside surface of one rotor. I do agree with those who said they had a similar problem (high-pitched whining noise especially when backing up), and then several hard braking experiences solved it by cleaning the built up rust and etc. from the rotor surfaces. In my case the whining was eliminated by a fun day at autocross!

 

[DasCC]

Thank you for posting the video as it enabled me to confirm we have the exact same sound. We drive almost exclusively in B mode in stop-and-go traffic where one pedal driving is a gift. The brakes are used very little and the explanation of a little rust or dust on the pads and rotors made sense.

I took a 10 minute spin with lots of brake applications and the low speed squeaking (identical to the video at the start of this thread) is gone.

I would like to add this is after a dealer visit where they replaced the bearings, strut mounts and had to realign. All thankfully under warranty.

I'll have to give this a try. Jumped in the e-Golf (primarily the wife car) and it was make a noise similar to what the OP mentioned at take off.

 

[msvphoto]

We don't use B Mode. I had all four wheels off for the first time in our ownership last Saturday. ~51k miles. The brakes (pads and rotors) looked like as if I just installed them, not over 50k miles old. No glazing or rust (and I live near the ocean), but hardly any noticeable wear either. I can see these brakes lasting to 100k or more miles easily.

 

[mpulsiv]

What's the consensus to use "B" mode on demand? Some of us come from 3 pedals and have an itch to shift I have been treating "B" mode like downshift. It's truly awesome.

Someone mentioned that one must take foot off the pedal when switch drive modes (e.g. D1, D2, D3, B) due delay in re-calibration. Nothing relevant was mentioned in owner's manual. For example, when I'm in "B" mode, I don't take my foot off the accelerator when I shift to "D" mode as I enter freeway.

I just found out that brake pads don't come into play until your braking demand exceeds the stopping force of the regen system. This raises the question why bother to use anything by "D" mode?

 

[Szyszka]

What's the consensus to use "B" mode on demand? Some of us come from 3 pedals and have an itch to shift I have been treating "B" mode like downshift. It's truly awesome.

Someone mentioned that one must take foot off the pedal when switch drive modes (e.g. D1, D2, D3, B) due delay in re-calibration. Nothing relevant was mentioned in owner's manual. For example, when I'm in "B" mode, I don't take my foot off the accelerator when I shift to "D" mode as I enter freeway.

I just found out that brake pads don't come into play until your braking demand exceeds the stopping force of the regen system. This raises the question why bother to use anything by "D" mode?

Love the B mode as well and I also switch in and out it as needed.

Have not heard anything about the 'foot off the pedal' when switching between the modes.

I use D sometimes when following a car and noticing they are just a tad slower. Rather than tapping brakes, shifting to D1 or D2 allows me to slow down, maintain a safe distance, and - most importantly - not use the brakes. I imagine B would work the same except it's much more stronger and requires the use of accelerator pedal to work more/less like any of the D modes.

 

[in2insight]

I drive mostly in D2, sometimes in B.
Question, when shifting from B back to D why does the shifter go to N first?
I tried to find the answer in the manual, but came up short.

 

[mpulsiv]

I drive mostly in D2, sometimes in B.
Question, when shifting from B back to D why does the shifter go to N first?
I tried to find the answer in the manual, but came up short.

Interesting. How do you know that it shifts into "N"? If it does, then the purpose behind it is to re-calibrate for regen so a driver doesn't have to take the foot off the accelerator.

 

[Szyszka]

I drive mostly in D2, sometimes in B.
Question, when shifting from B back to D why does the shifter go to N first?
I tried to find the answer in the manual, but came up short.

Wait, how are you shifting from B to D? You're supposed to tap it backward, not forward. Are you pushing it forward and therefore into N?

 

[JoulesThief]

I only shift to d1, d2 and then d3 with my foot off the accelerator.

I will usually be slowing down for a stop sign or stop light, so my foot is already covering the brake, if needed.

When I come to a complete stop, or if the light turns green, I just hold the shifter to the right side, for a full second, and it puts me right back into "D" mode.

I rarely use "B" mode. I don't find it necessary.

Timed properly, with a little bit of planning, D1, D2, and D3 are my "one foot" driving modes.

 

[mpulsiv]

I fail to understand why bother with regen. After all, your brake pads don't come into play until your braking demand exceeds the stopping force of the regen system. As soon as you touch the brake pedal, regen kicks in sequential order: D1 -> D2 -> D3 -> B -> your brake pads. So, why bother?

On a different note, here's the screenshot from the owner's manual. If I understand this correctly, we must take foot off the pedal when switch drive modes (e.g. D1, D2, D3, B) due delay in re-calibration. Please chime in.