MervinsOnlineID
Posts: 28
Joined: Tue Jan 10, 2017 1:59 pm

Driving in B mode often can cause issues?

Tue Aug 22, 2017 11:05 am

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/y4oeq1qiu96zn ... M.mov?dl=0
2016 VW e-Golf SE Reflex Silver Metallic with DCFC

johnnylingo
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Re: Driving in B mode often can cause issues?

Tue Aug 22, 2017 1:03 pm

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.
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MervinsOnlineID
Posts: 28
Joined: Tue Jan 10, 2017 1:59 pm

Re: Driving in B mode often can cause issues?

Tue Aug 22, 2017 3:15 pm

^^^ 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.
2016 VW e-Golf SE Reflex Silver Metallic with DCFC

f1geek
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Re: Driving in B mode often can cause issues?

Tue Aug 22, 2017 4:02 pm

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.
2017 e-Golf LE, Multi Coat White with Black Vegan Leather interior

RonDawg
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Re: Driving in B mode often can cause issues?

Tue Aug 22, 2017 10:11 pm

MervinsOnlineID wrote:^^^ 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.
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NeilBlanchard
Posts: 298
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Re: Driving in B mode often can cause issues?

Wed Aug 23, 2017 11:51 am

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
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Re: Driving in B mode often can cause issues?

Wed Aug 23, 2017 6:48 pm

Did they fix it under warranty?
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whyeGolf
Posts: 11
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Re: Driving in B mode often can cause issues?

Thu Aug 24, 2017 3:23 pm

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.
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MervinsOnlineID
Posts: 28
Joined: Tue Jan 10, 2017 1:59 pm

Re: Driving in B mode often can cause issues?

Fri Aug 25, 2017 3:44 pm

forbin404 wrote: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!
2016 VW e-Golf SE Reflex Silver Metallic with DCFC

treitenbach
Posts: 1
Joined: Sun Oct 06, 2019 5:32 pm

Re: Driving in B mode often can cause issues?

Sun Oct 06, 2019 5:39 pm

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.

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