[Bimmerfun82]

Final update they knocked 45% off the cost
Nice gesture

[Westside Guy]

Originally Posted by Bimmerfun82

Final update they knocked 45% off the cost
Nice gesture

That means you are paying 55% of something they should have covered to begin with!!!

[Bimmerfun82]

Originally Posted by Westside Guy

That means you are paying 55% of something they should have covered to begin with!!!

Oh believe me I understand this

There will be some phone calls and/or letters to BMWNA

[tracer bullet]

If you are handy - take off each wheel one at a time, plus any spacer, and clean it up. Lightly sand anything off the surface of the hub, each side of the spacer, and the inside of the wheel (lightly sand means no machines, just your hand and some 200 grit). Mostly looking for any pieces of junk that could possibly be in there.

Bonus if you can clean the spots with a rag and IPA or some other cleaner that won't stick around (no oils).

Next go out for a drive, find a long empty road, and do a bunch of high speed "almost" stops. Like 60 to 10, maybe a half dozen times in a row. You are basically evening out any brake pad material on the rotors. You probably have grippy spots where more pad material (the binding adhesives in the pads) exists than on other spots of the rotor. Even that stuff out and scrub most of it off. You can repeat this process too. If you start to feel brake fade, quit. And be sure that after you feel like you're done, you have a decent length drive ahead so you don't use the brakes at all for a while or you will undo your work.

All but guaranteed you'll solve the issue yourself. This almost always works. And it's free to try.

You're basically doing a new brake bed-in procedure. There are many ways but the gist is the same.

https://www.brembostoreusa.com/blog/...ial%20transfer.

And if that does it, you need to start driving harder And think of situations where the brakes got warm and you sat on them a while, like some time spent having a little fun and then waiting at a street light immediately afterwards.

[StanDiego]

Originally Posted by tracer bullet

All but guaranteed you'll solve the issue yourself. This almost always works. And it's free to try.

You're basically doing a new brake bed-in procedure. There are many ways but the gist is the same.

https://www.brembostoreusa.com/blog/...ial%20transfer.

And if that does it, you need to start driving harder And think of situations where the brakes got warm and you sat on them a while, like some time spent having a little fun and then waiting at a street light immediately afterwards.

If the rotors are truly warped, that procedure won't fix it. Similar to a frying pan than has been overheated and cooled too fast leaving a pan that won't lay flat, you can't heat the surface back to straight.

The only thing that would work if they're not warped too bad is to have the rotors turned on a lathe but that's not really an attractive option these days all things considered.

[tracer bullet]

Originally Posted by StanDiego

If the rotors are truly warped, that procedure won't fix it. Similar to a frying pan than has been overheated and cooled too fast leaving a pan that won't lay flat, you can't heat the surface back to straight.

Yep I totally get it. I'm just saying 1) They probably aren't actually warped and 2) If they are it can't hurt to try the bed-in procedure first to be sure.

[Bimmerfun82]

Originally Posted by tracer bullet

Yep I totally get it. I'm just saying 1) They probably aren't actually warped and 2) If they are it can't hurt to try the bed-in procedure first to be sure.

They were definitely warped. I expected one or two fronts, not all four. The braking performance was terrible, especially in the wet and at high speeds. Even at low speeds with light pressure. They were fine for the first 7000 miles and then something went wrong.

I’m still scratching my head as to how this happened. One theory is from the m2 forums, that this car sat at the port for a while. It’s a 2022 MY that I took delivery (new) on 1/31/2023. Did it sit for a while, did the rotors gather some rust? I have no evidence of that, but I could look into it or bring it up in my love letter to BMWNA.

But given the fact they were fine for so long, it could be the spacers. Or some weird phenomenon. Who knows.

[Horseman]

I have a hard time with ... it sat too long.

There are folks that leave their cars covered up and in their garage for 4 months in the winter. I doubt a few weeks at the port is going to be the cause of severe warping.

[Bimmerfun82]

Just throwing darts 🎯

[///M TOWN]

Originally Posted by Bimmerfun82

Just throwing darts 🎯

Well it makes me want to stick to plans to upgrade discs and pads all around

Keep driving like you normally do and keep us posted how the replacements work out

[Bimmerfun82]

I will.

My consolation is I still saved a fortune over a 911T.

Getting after it, hopefully Friday

[///M TOWN]

Originally Posted by Bimmerfun82

I will.

My consolation is I still saved a fortune over a 911T.

Getting after it, hopefully Friday

Here is something to think on…

Remember, these are not M Compound Brakes

They’re sport brakes with soft paws… Nothing close to your lovely retired G80

[Bimmerfun82]

Originally Posted by ///M TOWN

Here is something to think on…

Remember, these are not M Compound Brakes

They’re sport brakes with soft paws… Nothing close to your lovely retired G80

Yes. The M40i is not even close to an M in that sense. And this is something I didn’t consider until yesterday.

For my driving style do I need to order an M2 or keep dealing with this? I don’t really feel like doing aftermarket brakes now after this warranty debacle.

[stlcdr]

From my point of view - obviously my own non-expert opinion - with the springs and spacers giving a greater performance capability (real or otherwise) it allowed the car to be driven much harder than normal. At this point, there’s always a weakest link.

In this case, the brake capability was potentially exceeded. Maybe driven hard, then stopped too long with brakes applied? That’s what I can think of why it would affect all four corners.

[Bimmerfun82]

I agree with your science, but the crazy thing to me is this is a sports car and a BMW. It should be able to handle non-track duty even with the springs and spacers. Besides, the car is relatively light, and I don’t run that hard on the brakes.

BMW is assuming leisurely driving with this car and uses the lousy stock springs as a boundary to performance.

That, or only the spacers were the problem.

Again lesson learned but where do I go from here… that’s the real question I’m faced with now. Drive the car and see if it happens again or trade it.

[tracer bullet]

Originally Posted by Bimmerfun82

They were definitely warped.

How do you know? Did they put it up in the air, take off the wheels, get a dial indicator or something similar out against the rotor, turn the wheel, and see it? Or are you just pretty sure because the steering wheel shaked when you hit the brakes?

Originally Posted by Bimmerfun82

... and I don’t run that hard on the brakes

This is exactly how you can get uneven pad deposits. Being more aggressive on the brakes is actually better. And being super aggressive following the bed-in procedure (even though yours aren't new) may solve it by somewhat getting you back to a like new condition.

[ebirotedu]

The dealer’s justifications for denying a warranty claim for the brake rotors sounds pretty hand-wavey to me (it’s the spacers, or the lug bolts, or the springs… maybe; a spring change could affect damping and ride quality, and different rates could cause the shocks/dampers to work harder, run hotter, and wear faster, but I just don’t see any way to connect to this and rotor warping absent some other accelerated wear like cupped tires showing evidence the suspension wasn’t keeping the car glued to the road)

It doesn’t sound like they shared any sort of theory with you about that either, right? The just denied the claim saying, in effect, “Mods!”

I don’t think they know that anything you did aftermarket is in fact responsible, but I imagine BMW NA has a policy of denying warranty claims in cases where a customer has had modifications done and BMW can plausibly claim that the modifications MAY have been responsible. That your dealer suggested undoing the mods and bringing the car to another dealership to make a warranty claim leads me to believe that they’re not responsible for the policy, but are required to enforce it.

My viewpoint is informed by a couple videos on YT yesterday by an attorney in Detroit whose entire practice is lemon law, and he said, in essence, that when a manufacturer denies a warranty claim like this you can take the manufacturer to court (it often takes a couple years to get to trial). But then it comes down to whether the jury believes your expert or whatever expert BMW puts on the stand. If you win, you get your court costs covered in addition to some other financial relief for the issue being litigated, but otherwise it’s expensive - he cited $10k, usually payable up front since it’s hard to know which expert the jury will believe, or more in fees. Naturally, manufacturers are willing to roll the dice because they win as often as not, and most customers don’t want to front the money, or invest the time, unless the financial stakes are significant.

The most concerning aspect of all this is that of not knowing why warping occurred in the first place and whether this would have happened (a) if you hadn’t done the same mods, or (b) if the dealer had installed the same parts making this a valid warranty claim with the same dealership.

Originally Posted by Bimmerfun82

I agree with your science, but the crazy thing to me is this is a sports car and a BMW. It should be able to handle non-track duty even with the springs and spacers. Besides, the car is relatively light, and I don’t run that hard on the brakes.

BMW is assuming leisurely driving with this car and uses the lousy stock springs as a boundary to performance.

That, or only the spacers were the problem.

Again lesson learned but where do I go from here… that’s the real question I’m faced with now. Drive the car and see if it happens again or trade it.

[ebirotedu]

Also, like tracer bullet asked, would be good to know if the rotors are warped or maybe have high spots from brake pad deposits - the latter is more common than warping, I think.

And I did a quick search to see if the A90 Supra 3.0 has any sort of front brake warp issues, and didn’t find much. Presumably a lot more people are taking their 3.0l Supras to the track, so I’d expect that if the front brakes weren’t up to managing a few hot laps there’d be a good bit of internet commentary to that effect.

The Z4 M40i and 3.0l Supra seem to have interchangeable pads, so I would assume they use the same brakes: https://www.supramkv.com/threads/sup...e-as-z4.10763/

[Bimmerfun82]

Originally Posted by tracer bullet

How do you know? Did they put it up in the air, take off the wheels, get a dial indicator or something similar out against the rotor, turn the wheel, and see it? Or are you just pretty sure because the steering wheel shaked when you hit the brakes?



This is exactly how you can get uneven pad deposits. Being more aggressive on the brakes is actually better. And being super aggressive following the bed-in procedure (even though yours aren't new) may solve it by somewhat getting you back to a like new condition.

They took the wheels off and ran their tests to confirm warping. No reason for me to disbelieve them given my observations.

I did actually push the brakes, but I didn't track the car. I drive in the mountains and don't baby them that's for sure. The brakes were even and fantastic for 7k miles, then things went south.

[Bimmerfun82]

Originally Posted by ebirotedu

The dealer’s justifications for denying a warranty claim for the brake rotors sounds pretty hand-wavey to me (it’s the spacers, or the lug bolts, or the springs… maybe; a spring change could affect damping and ride quality, and different rates could cause the shocks/dampers to work harder, run hotter, and wear faster, but I just don’t see any way to connect to this and rotor warping absent some other accelerated wear like cupped tires showing evidence the suspension wasn’t keeping the car glued to the road)

It doesn’t sound like they shared any sort of theory with you about that either, right? The just denied the claim saying, in effect, “Mods!”

I don’t think they know that anything you did aftermarket is in fact responsible, but I imagine BMW NA has a policy of denying warranty claims in cases where a customer has had modifications done and BMW can plausibly claim that the modifications MAY have been responsible. That your dealer suggested undoing the mods and bringing the car to another dealership to make a warranty claim leads me to believe that they’re not responsible for the policy, but are required to enforce it.

My viewpoint is informed by a couple videos on YT yesterday by an attorney in Detroit whose entire practice is lemon law, and he said, in essence, that when a manufacturer denies a warranty claim like this you can take the manufacturer to court (it often takes a couple years to get to trial). But then it comes down to whether the jury believes your expert or whatever expert BMW puts on the stand. If you win, you get your court costs covered in addition to some other financial relief for the issue being litigated, but otherwise it’s expensive - he cited $10k, usually payable up front since it’s hard to know which expert the jury will believe, or more in fees. Naturally, manufacturers are willing to roll the dice because they win as often as not, and most customers don’t want to front the money, or invest the time, unless the financial stakes are significant.

The most concerning aspect of all this is that of not knowing why warping occurred in the first place and whether this would have happened (a) if you hadn’t done the same mods, or (b) if the dealer had installed the same parts making this a valid warranty claim with the same dealership.

Thank you. This was an $1800 lesson learned and the way I look at it is if I had purchased the extra protection up front it would have cost more and been less fun to drive for the last 8k miles anyway without the mods. Chalk it up to no more than that, I don't plan on pursuing legal action.

What I may do is trade cars. Very real possibility. And that sucks because I love my Z4.

[tracer bullet]

Originally Posted by Bimmerfun82

They took the wheels off and ran their tests to confirm warping. No reason for me to disbelieve them given my observations.

I did actually push the brakes, but I didn't track the car. I drive in the mountains and don't baby them that's for sure. The brakes were even and fantastic for 7k miles, then things went south.

Got it. You never mentioned that. And earlier you said you weren't hard on the brakes.

Anyhow - good luck. I do mean it.

[Bimmerfun82]

Originally Posted by tracer bullet

Got it. You never mentioned that. And earlier you said you weren't hard on the brakes.

Anyhow - good luck. I do mean it.

Sorry. Thanks!