Funny VW says this is a reason why they did rear drums on the ID.4

 

This discussion started in another thread but should probably be broken out separately.

Previous post: XC40 P8 deliveries delayed?
I'm not sure I've ever hard brakes rust that severely, especially not for sitting over night in a garage. I think this could be corrected with updated rear brake pads that are less rust prone.

A previous software update (week 5) supposedly included the following:
"Optimization of the automatic function that cleans the brake discs."

 

I've been exclusively using OPD, so lots of regeneration braking and little mechanical braking. I've noticed when leaving my garage a dragging sound, which I believe is the rust on the calipers. I haven't noticed any effect on performance, like needing extra acceleration to break the calipers free.

 

I would get that dragging scuffing noise even on our Acura RDX.

 

For what it's worth, I got the same thing on my BMW i3. As someone else said, it seems to be a pretty common thing and not necessarily something to worry. Of course, I'm not a mechanic, so take that with a grain of salt.

 

You can also break hard from 40 to stop somewhere safe every now and then to polish off the pads.

There is also I read an option to get porche break pads which I believe are tungsten carbide. Personally I am going to use the braking hard method. When the wives or dog are not in the car

 

I started this discussion on a previous thread. It took 4 days, 3 hours to get my car back. I thought they were going to ask for ransom! Got 3 different explanations as to why it took so long and why it occurred. Not a mechanic but as best I can tell pad stuck to caliper on passenger rear wheel but it took a while to get to that conclusion and then to get correct parts. Also car had to be checked out by regional tech manager, which I think was a good move. My take is that since this is a new offering they are being particularly careful in how they approach problems and also they are obviously still learning about the car at the dealer/ regional level. The car drives perfectly now but it hasn't rained since I got it back. Time will tell but so far so good.

 

Same boat. Car been at dealership for days they still not sure what they’re looking at. Question: Do you know if any parts were replaced and or fixed ?

thabks !

 

This discussion started in another thread but should probably be broken out separately.

Previous post: XC40 P8 deliveries delayed?

Because the XC40 Recharge (and other BEVs) use regen for a considerable amount of their braking, they don't use their brakes as often. This leads to less brake wear (good), but also allows the rotors to build up more surface rust. This isn't normally an issue but a couple of us have noticed after driving in the rain that the vehicle can have a hard time after it has been parked over night because the brakes are rusting to the pads a considerable amount (more than I've ever experienced before). This is pretty formal for all cars but there seems to be an excessive amount of it happening with the XC40s.

For the last few day's we've had quite a lot of rain and I've had this happen a few times now. This morning the brakes were very stuck, the car actually squat a good bit before it finally broke free. Once it broke free, there was an audible noise from the rear that I believe was the brake pad rubbing on a high spot from the pad and rotor rusting together. This went away after an application of hard braking and everything sounds fine now and my 20 mile commute went normally.

I'm not sure I've ever hard brakes rust that severely, especially not for sitting over night in a garage. I think this could be corrected with updated rear brake pads that are less rust prone.

I wished I had seen your post first. I had started a thread about “Brake Problems” after I decided for the car to get towed to Dealership after 15 miles of loud “thudding sound” which I didn’t think was “normal” in any circumstances. It went down hill trying to get the car in Reverse out of garage and the word “squatting” you’d used is perfect explanation. It was certainly doing that then a super loud “thud” as if it was finally “released” then the Swedish thudding loud sounds as the wheels turn
My car is still at Dealership since Thurs. by time it got there by tow, the tech didn’t hear anything. I even drove with him and sure enough didn’t hear anything.
Supposedly they’re waiting for a 3rd party tech to further check to conclude issues and decide whether or not they will release the car.
Question : Has the noises return ? Did the Dealer change any parts ?

thanks !

 

Problem has not returned.

Work order shows noise coming from right rear caliper sticking causing brake pad material to separate and stick to rotor. Replace right rear caliper and pads and bled brakes. Repairs inspected by District Tech Rep.

Car was repaired at North Point Volvo, Alpharetta. GA. Service Mgr might be able to offer your service people advice. Also understand Dyer and Dyer Volvo, Chamblee. GA had a car in at same time mine was in with exact same issue so they too might be able to offer assistance. District Tech Rep for Atlanta area should have insights from both repair jobs.

Good luck.

 

For what it is worth this problem has not replicated itself to the same extent for me since my initial post. I'm not sure why that would be the case as I've driven in rain a few times but I would speculate the pads wearing in to be responsible for the change. I still get a little bit of "stickage" but it's comparable to what happens with any car at this point.

 

Great to know ! Thanks for the feedback. Just now I had shared messages on this thread with the service Mgr to give him a head start. I found out my P8 is the first one at their service station, so needless to say, they have NO clue nor experience of how best to approach it. Aiyai yai yai….

 

Upon Tech's independent findings, I was informed that there were signs of the Brake "chipping" - so they have decided to replace the Pads and Rotors.
I find it interesting those have to be replaced when the Car is only a few months old since manufactured. But HEY, thanks for this Forum, I was persistent that they check what other Owners have shared, and what other Dealers had done. From there, the Techs couldn't just "dismiss" the issue and release the car as it DIDN'T make any noises AFTER it had been dropped off by the Tow Truck ! I even drove the Car with the Service Rep later that day, sure enough NO thudding or sounds coming out but persisted for them to look thoroughly (had shared posts from this thread) as I wouldn't have had it towed for NO reason!

Once I get an official work order, I will post the update in case other New Owners search for a thread on "Brakes", they'll be able to get more insights.

THANK YOU all !

 

Some design that a new car with low miles is having brake and rotor issues already.

 

I was talking with a co-worker, who said "time to switch to stainless steel". This got me curious, so I did a little reading. It sounds like SS rotors are available, but not ideal for brake rotors. Iron rotors have better braking characteristics and handle heat dissipation better.

But I wonder, since our cars use regen for the majority of stopping duties, whether SS rotors make sense.

Idle thoughts....

 

Ceramic Pads would probably solve this issue…

 

There are expensive and better breaks from Porsche that I do believe you can get. It sure how much they would cost.

 

Redirect Notice

 

Went to dealer after work to just show up (tired of literally no one calling for uodate even after leaving messages - GREAT customer service there after ur new car has been sitting there since last Thursday - ok I’m done ranting)- Amway got there, the the parts (Pads and Rotors) did arrive later afternoon - and they showed me these pics…

Talk about pads totally sticking to the rotors !!! It was explained thatprobably after rain and moisture build up etc, the pads just stuck to the rotors. The loud thud and car squatting before it finally reversed was when the rotors finally moved and pads were “yanked” hence all the jagged craters - it’s supposed to be a smooth surface all around.
The Service Manager bad the guts to ask me to wait another 2 days to pick up on Thursday Becasue he wasted too “make sure” it was ok after new parts installed.
I told him it’s been left almost a week and it’s STILL not prioritized to be fixed ? That they have all afternoon today and all day tomorrow - CMon! 3 week old new car, then at dealer 1 week and ur still telling me to wait another 2 days ?
I was like “ I’m sorry but r u kidding me right now ?????” I questioned why at this point my car waiting in line for a week and still not being prioritized???
After the Seevice Mgr sees fumes coming out of my head he’s like “ok …ok….when would I like to lick it up tomorrow ?” I said “I’ll give you All day Tomorrow and come right before you close to pick it up. But I’m done trying to get hold of someone to tell me stats of my new car - I’m NOT gonna deal with this BS another 48 hours”
So let’s see if they will get it done. If not I’m gonna make a scene !!!! Ridiculous !!!!

 

Yay for getting them to look after you. Sad you had to do it that way.

Not driven the car for 3 days and I put it away wet. Eeeps. Will be anxiously driving it later.

 

Yay for getting them to look after you. Sad you had to do it that way.

Not driven the car for 3 days and I put it away wet. Eeeps. Will be anxiously driving it later.

Oowww do tell ! That was me - driving in rain for 2 days then no driving 3 days. Hard to believe it goes bad that quickly simply cannot be.
People drive in rain and snow so it shouldn’t be acting up that way.
but all these experiences are keeping everyone more aware

 

Alas when you out an ice car to bed it’s breaks are normally very very hot and ours are cold and wet something really does need to change. Maybe a redesign of break material.

I am also worrying/wondering what is the best thing to do when the breaks are grinding so we do not get the damage yours have. I assume they come from the super stick event but are they getting damaged every time they stick. . .

 

Alas when you out an ice car to bed it’s breaks are normally very very hot and ours are cold and wet something really does need to change. Maybe a redesign of break material.

I am also worrying/wondering what is the best thing to do when the breaks are grinding so we do not get the damage yours have. I assume they come from the super stick event but are they getting damaged every time they stick. . .

The unsettling part is it’s not even a continuous grinding sound. It’s more of a “thud-thud-thudding” sound as the wheel turns. It’s as if something is stuck to rotor-wheel that each time it spins it makes the sound. So the faster you go the frequency of the thudding increases. A buddy of mine witnessed it and he climbed underneath the car to look to make sure nothing physical got caught underneath.
So needless to say if it acts up again, back it goes to the Dealer.

 

This does not bode well for the winter. Oh well just have to drive it every day which was the plan that said I also did not plan to not drive for 3 days. Life happens be nice if the car was not a surface welded block when we come back to it

 

O

Its GOT to be just a random occurrence on mine …or a very very few handful of owners to consider them as “exceptions”. Otherwise Volvo should consider announcing a Recall.

 

Interesting article that dovetails with thoughts above about the reason why drum brakes might be a better idea for EV's

Why old-fashioned drum brakes may be the way of the future for EVs - Autoblog

It may seem counterintuitive, but old-fashioned drum brakes are making a comeback in some of the most futuristic cars.

www.autoblog.com

 

Good article, thanks! I'm a software engineer, not a mechanical engineer, but I've been pondering this rusty-brake issue a fair bit lately. The drum-brake approach makes a lot of sense.

If the rears are drums with parking brakes, and the front are disks and don't engage with "P" (park) mode, then we shouldn't have issues with pads/rotors fusing together with rust.

 

Drums might work in the future if they can get the Same performance but for now disc = faster breaking = safety.

Another reason Evs have 4 discs for better performance is the increased weight of the car. More weight means more breaking needed to get the same stopping distance of a lighter vehicle.

Apart from the emergency stopping situations sounds like drums would win. But I for one want every inch of reduced stopping distance I can get when the world goes wrong.

 

About 80% of the stopping power comes from front brakes anyway, so drums in the back aren't that much of a compromise. Again, software guy here, but... it makes sense to me.

 

There is a reason they went to 4 discs bs 2 discs 2 drums for the EVs and I assume they were aiming to optimize stopping distance.

Also Weight distribution in an ev is different than an ice.

Hence our power distribution is 50/50 vs ice solutions that do a front bias in awd. ( it could also be argued that our power distribution is 50/50 as that is the easiest way to do it with symmetrical electric motors. Some cars do bigger in the rear I read)

During deceleration you do get a weight shift that adds more weight as the car rocks forward to the front but I doubt breaking is actually 80:20 on our car. Though I have a degree in physics I also went software engineer professionally so there could well be some mechanical engineering I am missing here.

All in all though I trust that Volvo chose this break configuration to minimize breaking distance. The question remains whether there is some quality control issue causing some breaks to fail faster (stick more, surface weld more) or whether the whole system just does not work well in the wet real world day to day use and they did not plan for this.

 

Well 5 weeks after having my pads and rotors it has happened again. They were seized pretty bad as the clunk was loud and the car jerked. Rolling without applying brakes initially had a grinding/rubbing noise then it went to only when brakes were applied. This was still happening after my 12 mile drive to work. Reaching out to Volvo and dealer to schedule repair. I assume pads/rotors again. My dashcam was not fully running for the clunk, but has the noise when driving.

 

Sorry to hear that.
Did you do anything different car wise last night? Wash it? Was it raining? I assume it is under cover. Are you near the sea? And joking is there a dog that likes to pee on your wheel?

It is strange that it has happened twice to your car. This does not seem like it would be something they would vary from car to car. It would be nice to know what is directly causing it so we could avoid doing the same and perhaps Volvo could fix the problem.

Good luck with the dealership. I hope they get it fixed ASAP.

 

I washed the car last weekend, but while I did not drive it I rolled it back and forth in driveway to apply the brakes rather hard to dry them. I have owned over 20 cars and none of them have had a seized brake or grinding like this. Some cars you would hear the rust grinding off after they sat after a rain or wash, but nothing like this.

 

Did you use the car since you washed it?

Rolling the car around at low velocity would not produce enough heat to dry them. Is why I get up to 40 mph before hard non abs breaking (the p button). I do this 3 times in a row after washing them and I have had no issues

I do agree though that this is something that is not exactly ideal! If I did not have to drive to hand wash the car I would be tempted to was it and put it away as well.

Good luck.