Rust centrifuge?

[Yeddheng]

Hello!

When washing the wheels on an M the brake discs emit a small amount of rusty water that you have to wipe off afterwards.
But now it seems as if this problem is getting more and more worse and when driving away there is a copious amount that centrifuge all over the wheels and its surroundings. Its a real mess.

How do you clean your wheels in order to limit this problem?

[Chris_D]

Could be an indication that your discs are corroding quite badly.

[Kernow-Z4]

Mine did this aswell, the discs were only 6 months old, after a bit of investigation the backing plate was the culprite.
A quick rub down and coat of paint seemed to solve the problem, strangly it only used to occur on the rear wheels.

[jamie_z4]

Paint your hubs?

[Yeddheng]

Thanks for your answers!

Paint your hubs?

They're aluminium and don't rust

Mine did this aswell, the discs were only 6 months old, after a bit of investigation the backing plate was the culprite.
A quick rub down and coat of paint seemed to solve the problem, strangly it only used to occur on the rear wheels.

It's coming from the inner core of the discs. The backing plates are just as new.

Could be an indication that your discs are corroding quite badly.

Could be, they are almost 10 years old and has 30k miles on them. I dont drive in the Winter or in rain so they look like new on the outside. They must be rotting away from the inside then…

[Angelus666]

When you’ve finished washing the car go for a drive around the block to rub off the surface rust and then a quick detailed on the wheels and you’re set.

On new disks I think you can spray clear coat onto them to help stop it happening from the start.

[Bing]

Happens on mine all the time, and the disks are not very old at all. It is common on Ms. Doesn't matter if I use wheel cleaner or not either. One way I can prevent it is to have been driving the car just before I wash it - the brakes are hot, and dry very quickly if you do the wheels first, very soon after you get back. Or, wash, and stick in the garage for a few days at the end of a weekend, again allowing them to dry before driving. Though you often get a puddle of rusty water even then.

The only other way to prevent it is to blow the water out the disks after washing, but you still get rusty water to clean up after doing that as well.

[G600]

You could try this to stop the rust, dilute it and spray in on the brakes when you was the car
https://www.bilthamber.com/atom-mac-164

[Yeddheng]

When you’ve finished washing the car go for a drive around the block to rub off the surface rust and then a quick detailed on the wheels and you’re set.

On new disks I think you can spray clear coat onto them to help stop it happening from the start.

Yea, that is exactly how I've been doing for the last 11 years but the problem seem to have escalated into a stupid amount of Sepang.

Regardig coating, I remeber there was someone making a DIY about that some years ago. My next set of discs defo going cleared!

Happens on mine all the time, and the disks are not very old at all. It is common on Ms. Doesn't matter if I use wheel cleaner or not either. One way I can prevent it is to have been driving the car just before I wash it - the brakes are hot, and dry very quickly if you do the wheels first, very soon after you get back. Or, wash, and stick in the garage for a few days at the end of a weekend, again allowing them to dry before driving. Though you often get a puddle of rusty water even then.

The only other way to prevent it is to blow the water out the disks after washing, but you still get rusty water to clean up after doing that as well.

Thanks for the support. I've tried washing the wheels first and last with no difference, but never hot. I dont think the discs have the mass to stay hot throughout the process tho, and there's a small risk of warping.

I've got a trick that has worked before but not anymore. I push the car a little bit when the wheels are done, just enough to let water out of the discs before it turns into instant coffee. After that I continue with the rest of the car.

You could try this to stop the rust, dilute it and spray in on the brakes when you was the car
https://www.bilthamber.com/atom-mac-164

This problem may originate from the discs getting more and more of deep-seated rust inside the core whitch hold more water than a smooth inner core. This chemical may help but how do you get it into the core. With a syringe through the drilled holes? But that is going to look odd at the local DIY car wash.

[BeeEmm]

You could try this to stop the rust, dilute it and spray in on the brakes when you was the car
https://www.bilthamber.com/atom-mac-164

I use Atom Mac every time I wash the wheels. Dilute it into a spray bottle. One of the main reasons that I bought this https://www.polishedbliss.co.uk/brands/metrovac was to blast through the drilled holes and dry every bit of the discs and calipers, as well as the wheels of course.

[srhutch]

I would run a drill through the holes just to clean any crap out of them.

[ronk]

Could be an indication that your discs are corroding quite badly.

As bad as this????

IMG_0444.jpeg (435.98 KiB) Viewed 1944 times

IMG_0443.jpeg (449.19 KiB) Viewed 1944 times

Just over three years old and 18k on our 335xD- Oh and no, I don't park it in a pond
I cost me £640 to replace them - The outside faces looked perfect so there is a real possibility that Chris_D thoughts could be correct.

[G600]

£640!?

[ronk]

£640!?

Afraid so!
Bmw price was £840 - they are the M Sport brakes and are the big disc option. They never felt that good from new, always sounded and felt rough - I thought just bedding in.
Over time I just accepted it but on its first MOT I got an advisor notice - this is the condition six months later at change

I suspect they were damaged/ defective from new!

Full BMW history but they didn’t offer any contribution towards replacement. Nor did they offer any reasons for the failure. Ie Lack of use, physical damage, disc or pad material - it would have been nice to know

[Yeddheng]

That was a bad one Ronk! Looks like a brake pad failure.
But You are lucky it wasn't the Z4M. The front discs, pads and labour will drain your wallet of twice as much!

I've just placed an order for some Atom Mac, I'll give it a try when it arrives