Braking in rain

[yobigd20]

It's worth noting for me that my experience with this is actually not consistent with the thread title "braking in the rain". I've had no issues braking in the rain at all. This only happens to me the first time I brake after washing the car. Any subsequent brake is fine.

 

[mknox]

1. If you have "surprises" or "drama" with your brakes, contact your nearest service center ASAP. Do not pass go, do not collect $200. Don't mess around with "scary" brakes. It's not smart on any car to be lackadaisical in addressing this.

Done.

2. Please don't be shy about posting confirmed info and feedback from Tesla. This is always good information.

Also done. To recap, they "serviced" the brakes to address sticking callipers. I'm not sure if this addresses the problem, but I haven't had any wet weather or car washes to find out yet.

3. If you feel the need to discuss problems in this area on TMC (or the TM forums for that matter) without any official response from Tesla, I don't have a strong opinion about that but PLEASE do #1 (and #2 if they have anything interesting to say) first.

One interesting note is that the fairly new loaner car I had exhibited the exact same behavior once on me. It was very slushy and wet. When I left work, re-gen was disabled (cold) and the first application of brakes was very "weak" until I stopped a couple of times and dried them out. That car had the Pirelli winter tire package with the Tesla Aero wheels.

- - - Updated - - -

It's worth noting for me that my experience with this is actually not consistent with the thread title "braking in the rain". I've had no issues braking in the rain at all. This only happens to me the first time I brake after washing the car. Any subsequent brake is fine.

Probably worth modifying the thread title to something like "Poor Braking Performance with Wet Brakes" or similar. I think the issue has to do with wet brakes regardless of how they got wet in the first place.

 

[Gizmotoy]

Concern: Customer states: Brake performance feels degraded in the rain. Customer feels like there is "no stopping power".
Pay Type: Warranty
Cause: Brake pads glazed over.

Correction: Brakes Discs & Calipers General Diagnosis

Confirmed poor braking performance, even in dry weather. Inspected pads and rotors and found normal glazing from lack of use. Performance also likely related to master cylinder, replaced on line 4. Burnished brakes and cleaned remaining pad glazing on rear brakes, working as designed.

Correction: Brake Pads and Rotors - Front - Set

Brake pads removed and replaced.
Part Qty
(1) FR BRAKE PAD & NOISE SHIM KIT (6006429-00-B)
(2) BLT CSK TRX M8x1.25x20 10.9-ZnAl-W (1004377-00-B)
(2) SVC FR BRAKE ROTOR W/ AS-CAST OUTER HAT (1025099-00-A)

IMO, this is the most interesting post in the thread. Glazed pads. A glazed pad would explain a lot of the things discussed in this thread. For those unaware, a glazed brake pad has a smooth/shiny surface. This is typically caused by overheating where the resins in the pad liquify and then solidify as a flat surface. This smooth surface reduces braking power, especially under wet conditions. There may be other causes of glazing, but the two I'm most aware of from track days are overheating and picking up contamination (like if you paint your rotors). If the pads can glaze from lack of use, that's something to keep an eye on. Once a pad is glazed, it's usually needs to be replaced, which is exactly what they did here.

What is concerning is the "normal glazing." As far as I'm aware, glazing is not a normal occurrence. Completely replacing the pads doesn't suggest this is normal, either.

Any mechanics with experience with low-use brakes in hybrids and EVs able to chime in, here? I know a fair bit about pads and brake diagnostics, but not on the low-use end of the scale.

 

[iffatall]

I have been closely following this thread from day 1, and to me, this sounds like a very critical safety issue. Not sure how Tesla is (planning to) go about addressing it, but the hush-hush way of individually contacting owners reporting on this thread is dangerous. At the very least, the existence of the issue should be acknowledged, and all owners should be made aware it, especially when the cause is still unknown/uncertain to make sure they are careful and no untoward incident happens.

I understand that Tesla may be afraid of the issue raising another wave of uproars in the media given the attention it's been getting, but not addressing the issue openly can prove to be far more damaging. Not to mention deliberating on everything for months is starting to be received as a very negative attribute by us loyal fans, even if it is to achieve perfection.

 

[dave]

I have been closely following this thread from day 1, and to me, this sounds like a very critical safety issue. Not sure how Tesla is (planning to) go about addressing it, but the hush-hush way of individually contacting owners reporting on this thread is dangerous. At the very least, the existence of the issue should be acknowledged, and all owners should be made aware it, especially when the cause is still unknown/uncertain to make sure they are careful and no untoward incident happens.

I understand that Tesla may be afraid of the issue raising another wave of uproars in the media given the attention it's been getting, but not addressing the issue openly can prove to be far more damaging. Not to mention deliberating on everything for months is starting to be received as a very negative attribute by us loyal fans, even if it is to achieve perfection.

Conspiracy theory much? There's nothing "hush-hush" about it. They reached out to me to fix a problem I talked about having ONCE in over a year of ownership. They also reached out fix my wiper blades I was talking about in another thread. This isn't a conspiracy to hide an issue. I don't even think there is a known issue yet. A few people on a forum mentioned some problems and they are looking into it, collecting data to see if there is an issue or not.

What exactly would you have them do? Sometimes I think talking about our issues on this forum does more harm than good...

 

[mitch672]

What exactly would you have them do? Sometimes I think talking about our issues on this forum does more harm than good...

I agree. I had an issue, I took it to the service center, and they fixed it. My car is an older, early production Model S (December 2012), I expected there would be a few trips to the service center, but just about every issue has now been addressed. You wouldn't get this from most manufacturers, Tesla has been exceptional how they've handled issues so far. I have yet to pay for a single repair visit to date, and I've been there a fair number of times.. The later VIN cars have far fewer issues, the cars are getting better, and they have learned a lot.

 

[iffatall]

Conspiracy theory much? There's nothing "hush-hush" about it. They reached out to me to fix a problem I talked about having ONCE in over a year of ownership. They also reached out fix my wiper blades I was talking about in another thread. This isn't a conspiracy to hide an issue. I don't even think there is a known issue yet. A few people on a forum mentioned some problems and they are looking into it, collecting data to see if there is an issue or not.

What exactly would you have them do? Sometimes I think talking about our issues on this forum does more harm than good...

I hope you are right, and I did not mean to suggest that there was any conspiracy. I too felt the same way as you at first, and have been quietly following the thread. But sine the thread was first started, the same issue has been reported multiple times, and I was merely pointing out that in my opinion, Tesla is taking too long collecting and analyzing data given the seriousness of the issue, no matter how rare it might be.

 

[Gizmotoy]

I have been closely following this thread from day 1, and to me, this sounds like a very critical safety issue. Not sure how Tesla is (planning to) go about addressing it, but the hush-hush way of individually contacting owners reporting on this thread is dangerous. At the very least, the existence of the issue should be acknowledged, and all owners should be made aware it, especially when the cause is still unknown/uncertain to make sure they are careful and no untoward incident happens.

I understand that Tesla may be afraid of the issue raising another wave of uproars in the media given the attention it's been getting, but not addressing the issue openly can prove to be far more damaging. Not to mention deliberating on everything for months is starting to be received as a very negative attribute by us loyal fans, even if it is to achieve perfection.

I don't think this is an attempt to hide the issue, as implied here, but rather get actual hands on cars exhibiting the issue so they can track down the cause and who is affected. That's a very good thing that's beneficial to owners, and IMO, making it out like it's some sort of shadowy conspiracy dissuades them from being proactive in the future. As far as we're aware, they've seen, what, two cars?

Conspiracy theory much? There's nothing "hush-hush" about it. They reached out to me to fix a problem I talked about having ONCE in over a year of ownership. They also reached out fix my wiper blades I was talking about in another thread. This isn't a conspiracy to hide an issue.

I feel the same. I've been contacted about trivial and important issues alike. At least once I had to apologize to a service center contact over a minor thing that Tesla Ownership told him he needed to talk to me about and I had planned on batching up with a bunch of other minor issues for a future visit. I have more annoying issues they're working on that I'd like corrected, so I didn't want to cloudy the issue with a bunch of trivial stuff. So most of the things I tell them can wait for my next service center visit, but occasionally they'll ask to see the car and I usually agree.

In any case, this is how vehicle service should operate.

 

[mnx]

I'm willing to bet we all know exactly who it is. LOL

Okay this sounds like someone trolling the NHSTA. Really sounds like he's reporting stuff he read in an internet forum, rather than a personal experience. Lame.

I had a car wash the other day in -15C conditions and had absolutely no trouble stopping afterwards.

 

[pilotSteve]

I don't think this is an attempt to hide the issue, as implied here, but rather get actual hands on cars exhibiting the issue so they can track down the cause and who is affected. That's a very good thing that's beneficial to owners, and IMO, making it out like it's some sort of shadowy conspiracy dissuades them from being proactive in the future. As far as we're aware, they've seen, what, two cars?


I feel the same. I've been contacted about trivial and important issues alike. At least once I had to apologize to a service center contact over a minor thing that Tesla Ownership told him he needed to talk to me about and I had planned on batching up with a bunch of other minor issues for a future visit. I have more annoying issues they're working on that I'd like corrected, so I didn't want to cloudy the issue with a bunch of trivial stuff. So most of the things I tell them can wait for my next service center visit, but occasionally they'll ask to see the car and I usually agree.

In any case, this is how vehicle service should operate.

I believe Tesla is actively interested and want to understand (not ignore) what is going on here. In fact by proactively contacting me and examining my car at the SC they are taking active steps here. Unfortunately they found no fault with my brakes and their next course of action is to have me recall dates/times of the two incidents so they can look at car logs.

Unfortunately I don't have any really good records of when this was so I can only offer them a range of possible dates.

Take away: next time this happens to ANYBODY they should call roadside assistance and notify them of what you observed and assuming you stopped without incident just observed reduce braking, they will download your car logs for further research.

 

[iffatall]

I believe Tesla is actively interested and want to understand (not ignore) what is going on here. In fact by proactively contacting me and examining my car at the SC they are taking active steps here. Unfortunately they found no fault with my brakes and their next course of action is to have me recall dates/times of the two incidents so they can look at car logs.

Unfortunately I don't have any really good records of when this was so I can only offer them a range of possible dates.

Take away: next time this happens to ANYBODY they should call roadside assistance and notify them of what you observed and assuming you stopped without incident just observed reduce braking, they will download your car logs for further research.

True. Proactively trying to figure it out is certainly better than ignoring it altogether.

 

[pilotSteve]

Email from my service advisor regarding his email to Tesla engineering yesterday:

On the first concern of the brake pedal feeling soft in the rain they seem to be aware of a similar issue and would like to install some updated shielding for the brake rotors. I have ordered the parts and will set up an appointment to get them installed when they arrive.

:smile:

 

[jcadman22]

IMO, this is the most interesting post in the thread. Glazed pads. A glazed pad would explain a lot of the things discussed in this thread. For those unaware, a glazed brake pad has a smooth/shiny surface. This is typically caused by overheating where the resins in the pad liquify and then solidify as a flat surface. This smooth surface reduces braking power, especially under wet conditions. There may be other causes of glazing, but the two I'm most aware of from track days are overheating and picking up contamination (like if you paint your rotors). If the pads can glaze from lack of use, that's something to keep an eye on. Once a pad is glazed, it's usually needs to be replaced, which is exactly what they did here.

Would glazing cause the brakes to squeal incessantly? I don't drive my car hard and therefore don't have a lot of hard stops. In fact, I'm quite the opposite, planning ahead and letting regen do most of the work. I HAVE experienced the issue where the brakes are unresponsive right after washing the car, but it's been isolate incidences, not necessarily rain related. The squealing brakes are REALLY annoying/embarrassing when you stop next to another car at a light or pull into a parking garage and greet the attendant with a nice loud screech.

 

[Rainbow]

IMO, this is the most interesting post in the thread. Glazed pads. A glazed pad would explain a lot of the things discussed in this thread. For those unaware, a glazed brake pad has a smooth/shiny surface. This is typically caused by overheating where the resins in the pad liquify and then solidify as a flat surface. This smooth surface reduces braking power, especially under wet conditions. There may be other causes of glazing, but the two I'm most aware of from track days are overheating and picking up contamination (like if you paint your rotors). If the pads can glaze from lack of use, that's something to keep an eye on. Once a pad is glazed, it's usually needs to be replaced, which is exactly what they did here.

What is concerning is the "normal glazing." As far as I'm aware, glazing is not a normal occurrence. Completely replacing the pads doesn't suggest this is normal, either.

Any mechanics with experience with low-use brakes in hybrids and EVs able to chime in, here? I know a fair bit about pads and brake diagnostics, but not on the low-use end of the scale.

The only brake glazing that I am familiar with is from excessive heat from high-speed or high load conditions.

Would glazing cause the brakes to squeal incessantly? I don't drive my car hard and therefore don't have a lot of hard stops. In fact, I'm quite the opposite, planning ahead and letting regen do most of the work. I HAVE experienced the issue where the brakes are unresponsive right after washing the car, but it's been isolate incidences, not necessarily rain related. The squealing brakes are REALLY annoying/embarrassing when you stop next to another car at a light or pull into a parking garage and greet the attendant with a nice loud screech.

I think brake squealing is usually from brake dust and or metal to metal contact.

Brake dust is from brake use, sometimes it can build up and cause noise.

Glazing can reduce braking effectiveness, especially in wet conditions. Glazing that I am familiar with is from high heat from high-speed and or high load.

 

[lolachampcar]

Squeal is a separate issue which Tesla has addressed. I find this a bit amazing as I've had both MB and Ferrari breaks that squeal and the factory did nothing to address the issue.

Anyone have the new heavier rotors that fix squeal?

 

[stevezzzz]

I'll add my experience with braking anomalies to this thread, FWIW. My car was built in September of 2012, has 19" OEM wheels and 23,000 miles on the odo. My driving style is normally heavily dependent on regen braking, though I probably use moderate friction braking several times in an average daily drive (that is, for more than just bringing the car to a stop after the regen cuts out under 5 mph).

1. I've experienced very weak friction braking on exiting a car wash, perhaps two or three times; it is not a given, however. Braking function returns to normal after a second or two.

2. I've never experienced unusually weak friction braking on the road in wet/slushy/snowy conditions (that is, no more so than other cars I've owned), though when I garage the car afterwards I have learned to expect the pads to stick to the rotors overnight and break loose with a disconcertingly loud 'clunk' when I drive away in the morning.

3. When the car wakes up from a sleep state I have to press the brake pedal up to three times before I feel the power assist come to life; until it does, I cannot put the car in Drive. My normal habit on entering the car is to put my foot on the brake pedal immediately, before the displays are fully functional, so that may have something to do with it. This behavior arrived with a firmware revision some time back; I don't recall which version. Prior to that I never noticed any delays with being able to put the car in Drive.

Sorry if some of this is slightly OT.

 

[dave]

Went to the same car wash yesterday, tested the brakes, and they worked properly. So who knows...

 

[agw]

Email from my service advisor regarding his email to Tesla engineering yesterday:

On the first concern of the brake pedal feeling soft in the rain they seem to be aware of a similar issue and would like to install some updated shielding for the brake rotors. I have ordered the parts and will set up an appointment to get them installed when they arrive.

:smile:

I have had the same issue and a number of scary moments. I have also reported it to my service center were we reproduced it by wetting the rotors with a hose.
A case was opened and it is great to see that Tesla has come up with a solution. I hope to get the same fix soon.
As far as the parking brakes getting stuck, which i also experience on occasion, it has been suggested to use the rain sensor to lightly apply the parking brakes so to keep the rotors dry. This would actually address both problems and would only be a software update.

 

[Lloyd]

deleted

 

[pilotSteve]

New update: Seems that Tesla engineering HAS been working this problem. They called my service advisor and asked that I bring my car in for a quick look so they can ship some new parts to attempt resolution of the 'wet brake' issue I raised.

Some details: seems that early cars (all sigs) have a shield intended to keep water from splashing the brakes that was removed starting with early production. They wanted to know whether I already have those shields (I do) and if not engineering would send a set for installation.

Second detail: most cars have a small "vibration damper" on the front rotors intended to reduce brake squeal. However it seems they may sling water onto the brakes which could cause this problem.

New front rotors and pads plus maybe some other goodies on order.

Nice to see Tesla taking this issue seriously and not ignoring it. Helps to have a great tech in Portland (Jon) who write up the trouble report and stayed in contact with me and engineering.