Resurfaced brake rotors to fix vibration, need further advice

[Lexigen]

So my brake rotors have been in pretty bad shape for a while now. Common issue with EVs where the friction brakes are seldom used. I make it a habit to turn regen to 0 to work the brakes, but my wife drives it more than I do and this is something she'll never do. The annoying thing is it will not remember regen 0 setting when the car is restarted, just like it will not remember iPedal, so it's not something I can set and forget for her.

Started around this past winter, the entire car shook quite severely when using the brakes at highway speeds. Of course not something my wife ever noticed until I drove it and decided to work the brakes. I took it out couple of times in the middle of the night and slammed the brakes at high speed. It lessened the vibration a bit but they still looked bad, with uneven deposits on the front rotors, and a ring of rust on the outer edge on the driver side rear.

Last week while I had the car at the dealer to do the update recall, I had them resurface the rotors and it totally cured the vibration. I asked my advisor if I should replace the pads but per the tech who worked on my car said it was not necessary. I took the car out early early in the AM to kind of bed in the pads to the new rotor surface, worked the brakes at high speed several times. As you can see in the picture the outer edge of the driver side rear rotor is still not making contact.

I wouldn't count on it, but figured while they had the brakes apart they would've lube the slide pins. Assuming they did, what else can cause the outer edge of the brakes to not engage? I'm going to take it apart myself and check the slide pins. Awaiting delivery of a Jack Rod before doing so. Should I replace the rear pads?

Driver's side rear after bedding:


Passenger side:

 

[Lalin]

Why would the rotors be in bad shape if like you say, there are seldomly used due to regen?
I would think that EVs with decent regen wear the rotors and pads a lot less than non EVs.

 

[Lexigen]

Why would the rotors be in bad shape if like you say, there are seldomly used due to regen?
I would think that EVs with decent regen wear the rotors and pads a lot less than non EVs.

My rotors were in bad shape not from wear but from the constant non-use, with rust and other deposits build up on the rotors causing brake shudder when actually using the friction brakes. I've had this same issue with another EV and even a hybrid. The other cars I hadn't kept for that long for me to have to deal with it. My GV60 is coming up on 3yrs ownership now.

I took apart both sides of the rear brakes. The pads weren't sliding that well but they weren't seized. The sliding pins were also fine. I did notice immediately just by looking at it that the driver's side pad was unevenly worn. This was confirmed using a caliper - the outer edge is 0.5mm thinner.

I did brush off and lubed the hardware. As you can see it is still making zero contact with the outer edge of the rotor. I washed the car and I always run it up and down the block to dry off the brakes and get as much as the water out of the nooks and crannies as possible. As you can see the rotor has a perfectly nice ring of rust. I order new rear pads.

Since nothing was seized, why did that brake pad wear unevenly?

 

[GV60Lem]

I think the issues is accelerated by the parking brakes as well.
Unlike older cars with separate brakes, a lot of newer cars, GV60 included, have electronically actuated parking brakes which engages by an electric actuator pushing the brake piston against the rotor.

 

[Lexigen]

I think the issues is accelerated by the parking brakes as well.
Unlike older cars with separate brakes, a lot of newer cars, GV60 included, have electronically actuated parking brakes which engages by an electric actuator pushing the brake piston against the rotor.

I agree. Actually I recently made it a habit to disengage the parking brake after driving it in the rain.

On the Mustang Mach E, there were reports of the rear brake pads having pieces broken off and stuck to the rotor.

TSB 21-2206 Vibration/Pulsation From Brakes - Brake Pad Material Stuck To Rotor

PDF ATTACHED TECHNICAL SERVICE BULLETIN Vibration/Pulsation From Brakes - Brake Pad Material Stuck To Rotor 21-2206 24 August 2021 Model: Ford 2021 Mustang Mach-E Issue: Some 2021 Mustang Mach-E vehicles may exhibit a vibration or pulsation from the brakes. This may be...

www.macheforum.com

Another:

Rain = Pads stuck to rotors

Hi all, I live in Florida and we recently had some rain and my brakes got wet. After driving down my street, which was flooded, I parked it and didn't drive it for 2 days. When I got in and put it in drive, I thought I had engaged one pedal driving, so I stepped on the gas and it makes a big...

www.macheforum.com

 

[Lexigen]

New brake pads installed and it immediately cleaned off that ring of rust driving it just up and down my block. I still need to do several high speed runs to properly bed them in. The question remains, why did the pad wear unevenly when nothing was seized, and it was only the driver side. For preventive measure, I will make it a routine to lube the brake hardware when I swap over to my winter wheels and tires.

Quick tip for you DIYers, I used an old 12V battery from a UPS to retract the parking brake mechanism to push the piston back. Connect the positive lead onto the rounded side of the connector to retract it, connecting the negative lead to it will push it out.

 

[Guru0006]

I was gettting mild vibration when braking so resurfaced front rotors. Vibration gone

 

[wighty]

New brake pads installed and it immediately cleaned off that ring of rust driving it just up and down my block. I still need to do several high speed runs to properly bed them in. The question remains, why did the pad wear unevenly when nothing was seized, and it was only the driver side. For preventive measure, I will make it a routine to lube the brake hardware when I swap over to my winter wheels and tires.

Quick tip for you DIYers, I used an old 12V battery from a UPS to retract the parking brake mechanism to push the piston back. Connect the positive lead onto the rounded side of the connector to retract it, connecting the negative lead to it will push it out.

Were the brakes generally easy to DIY? I have done probably 6 brake jobs but they were all basic brakes (Honda, Subaru) without something like the electronic brakes. Inspection done today and they said the brakes needed to be replaced "imminently" at 52k miles, 3 years old. We are in a high salt usage area for the winter.

Edit: I didn't drive immediately after but my wife did. She said she got warning alarms as soon as she got the car back. I just drove it and see alerts for "Check Brake system", "Check Inattentive Driving Warning System", and "Check Lane Safety system", and after I drove it on regen 0 and did some starts/stops I was able to get the wheels to lock on slamming the brakes from under 30mph (though I didn't push hard until probably 20mph), after that I got "Check ESC". It sounds like the electronic parking brake is engaging and disengaging okay when I hit the button. I ran an OBDII diagnostic check and got:
C1693 (Blind Spot Detection)
C1268 (ABS control unit)
C1841 (pre-safe seat belt... note I did bring this to the dealer to have done if that was related to the recall)
C1642 (Lane assistance/Front view camera)

The pad looks like it is decent to me as well.

Edit2: drove it for a little bit, then cleared the codes, went from 4 alerts to 2 and the dash alert changed to forward collision, parked and re ran the diagnostics and quickly all of the alerts went away early into the scan, and came back briefly near the end... Will see if they retrip with more driving.