Rusty brake disc?

[Matt2010]

I got my 2016 car late last week and it was sat in the all day heavy rain yesterday so had some rust on all the discs this morning.
I did a quick 3 mile journey dropping nipper off at nursery and did plenty of braking but I noticed one of the rear discs still had a lot of rust on the surface.

On the way back, I did some much heavy braking on purpose to try and clean it up but when home, there is still some rust on just the one disc.
Is this normal not to wear off after 6 miles and heavy braking? Car has only done just over 8k miles and was Audi approved and all other discs are nice and clean.
Pic of disc after the 6 mile journey:

 

[D0C]

Doesn’t look like it’s getting used at all. Do some repeated emergency stops and see if that clears it!

 

[Matt2010]

Doesn’t look like it’s getting used at all. Do some repeated emergency stops and see if that clears it!

I did a couple

 

[andy.h]

That looks like more than a days rain hitting the disk, I would go back to the dealer you got the car from and ask them to sort it out.

 

[Gnasher]

If it's not clearing off the face of the disc, check the back - if it's clearing off the back then the sliders have seized on the caliper.

It would need to be taken off the car, the slider pins removed, cleaned, greased and reassembled. Also, if it's been happening for a while, check the wear on the inside pad as it'll have be wearing quicker than all the other rear pads, although at 8,000 miles, hopefully not too much more.

Definitely worth getting it checked though.

 

[RS03_SEN]

Those discs look pretty scored mate. I’d be going back to the garage and telling them to sort discs and pads out free of charge.


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[T-800]

Had to change mine

Was getting an off pedal rotational squeak.

Turns out one of the discs wasn’t running true.

 

[Marshy]

Changed my rear discs and pads at 12k mainly because they were badly scored and looked crap.
My rear pads looked like this

Fitted Brembo rear discs and yellow stuff pads

 

[RS03_SEN]

Changed my rear discs and pads at 12k mainly because they were badly scored and looked ****.
My rear pads looked like this

Fitted Brembo rear discs and yellow stuff pads

Your discs still go rusty at the hub? Mine are only a few months on and rusty as hell. Look awful


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[Marshy]

Your discs still go rusty at the hub? Mine are only a few months on and rusty as hell. Look awful


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Before I fitted them I sprayed the bells with Hammerite smooth silver.
Now 10k in and a year with no rust yet

 

[RS03_SEN]

Before I fitted them I sprayed the bells with Hammerite smooth silver.
Now 10k in and a year with no rust yet

Ahh. I got someone to fit mine (rears) because I didn’t have the software to get the handbrake off.


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[Matt2010]

Got it booked in for next week. Cheers all

 

[T-800]

Got it booked in for next week. Cheers all

You dust shield is going rusty too........

Either it's been owned by someone near the coast or it's been sat around for a good while unused....

As said above, it's a 2 piece caliper that relies on 2 round slides for sideways movement as the piston applies pressure.

On mine i also noticed the pad lugs were causing one side to resist movement and this was causing the pad to stay in contact with the disc.

 

[Matt2010]

You dust shield is going rusty too........

Either it's been owned by someone near the coast or it's been sat around for a good while unused....

Could be the latter. 3+ year old car with only 8k miles covered.

 

[AudiNutta]

Had to change mine

Was getting an off pedal rotational squeak.

Turns out one of the discs wasn’t running true.

That looks like a nice quality disk, did it come with that coating on the bells? Any signs of rust?

 

[AudiNutta]

You dust shield is going rusty too........

Either it's been owned by someone near the coast or it's been sat around for a good while unused....

As said above, it's a 2 piece caliper that relies on 2 round slides for sideways movement as the piston applies pressure.

On mine i also noticed the pad lugs were causing one side to resist movement and this was causing the pad to stay in contact with the disc.

My shield have started to go rusty I was really shocked, mine isn’t near the coast and is in regular use and when not it’s in the garage. Very rarely sees rain.

Will have to get them off and powder coated one day, but I’ve got no facility to leave the car with no wheels on at home as I wouldn’t leave it outside like that so need to get it stripped and stored somewhere else.

 

[T-800]

That looks like a nice quality disk, did it come with that coating on the bells? Any signs of rust?

Good quality Brembo discs but only as a temporary thing as I’m soon swapping to Reyland 350 dia rear to match my fronts.

They come like this now which is why I went for them.

Also fitted similar to the GTD back in 2017.

 

[AudiNutta]

Good quality Brembo discs but only as a temporary thing as I’m soon swapping to Reyland 350 dia rear to match my fronts.

They come like this now which is why I went for them.

Also fitted similar to the GTD back in 2017.

Something I’d like to do but will be after I change my front discs for sure, spread the cost out. Will you keep your existing calliper setup and just use a bracket to extend your carrier from the hub?

The rears seem to take a bit of a kicking on these cars, minimal use and maximum corrosion and scoring as a result.. question is do I want to risk the same on a £700 pair of discs or do you think it will be ok? The small rears on these cars do look out of place.

 

[T-800]

Something I’d like to do but will be after I change my front discs for sure, spread the cost out. Will you keep your existing calliper setup and just use a bracket to extend your carrier from the hub?

The rears seem to take a bit of a kicking on these cars, minimal use and maximum corrosion and scoring as a result.. question is do I want to risk the same on a £700 pair of discs or do you think it will be ok? The small rears on these cars do look out of place.

Yes existing bracket moved further out

Bracket in the picture of the set below.

Bolted bells £650

Floating set up like below £850

They do a deal when buying both fronts and rears together.

 

[Marshy]

Something I’d like to do but will be after I change my front discs for sure, spread the cost out. Will you keep your existing calliper setup and just use a bracket to extend your carrier from the hub?

The rears seem to take a bit of a kicking on these cars, minimal use and maximum corrosion and scoring as a result.. question is do I want to risk the same on a £700 pair of discs or do you think it will be ok? The small rears on these cars do look out of place.

For me personally I find it’s the original rear pads that kill the discs.
My last car started scoring the rear discs at only 2k, I changed the rear pads and the discs cleaned up lovely.

 

[Matt2010]

For me personally I find it’s the original rear pads that kill the discs.
My last car started scoring the rear discs at only 2k, I changed the rear pads and the discs cleaned up lovely.

What pads did you go for?

 

[Marshy]

What pads did you go for?

On my previous car and this RS3 I’m running EBC yellowstuff rear pads and had no problems since.
Although the I’m running Ferodo pads on the front and have no complaints with them either.

 

[Matt2010]

Are the yellowstuff pads good around town and stop any low speed squeak?

 

[Marshy]

Having used Redstuff in the past I prefer the bite of the yellowstuff, I’ve never had any squeal from them and as much as I can tell with them being on the rear initial bite feels good.

 

[DW81]

Yes existing bracket moved further out

Bracket in the picture of the set below.

Bolted bells £650

Floating set up like below £850

They do a deal when buying both fronts and rears together.

Looks a great well made product there T800.

As you might know, I opted for the rs7 rear setup. Looks absolutely fantastic, and I’m feeling abit more bite now from the rear which I never got before. I thought this may have been a costly cosmetic enhancement mod at one point .
The only thing left to do is to get a set of wavy fronts now before the become obsolete

 

[msdmjb]

It might just be a slightly sticky piston, before spending any money try using the handbrake for a second a few times (all at your own risk ) to see if it cleans it up.

 

[T-800]

It might just be a slightly sticky piston, before spending any money try using the handbrake for a second a few times (all at your own risk ) to see if it cleans it up.

I hardly see how using the electronic handbrake even at low speed is going to sort this issue out......

It’s dangerous at low speed for one and isn’t very good for the pads / calipers etc because of the instance grab and subsequent lock up of the rear wheels.

If it’s a sticky piston etc then always best to strip the set up down and investigate while the caliper is in ‘lining change’ mode.

 

[msdmjb]

It will prove the functionality of the specific brake, if the caliper doesn't clean the disc then 'proper' problem perhaps.
And no its not dangerous in the right place at the right time, it is the emergency brake after all. It can be turned on for a second and as soon as the rear drops let go, no lock no slide no handbrake turn. It does squiddly diddly harm if only done a few times, it does trigger the abs.

 

[Matt2010]

Its under warranty from 'Used Audi approved' so will see what they say on Mon when they collect car from me.

 

[T-800]

It will prove the functionality of the specific brake, if the caliper doesn't clean the disc then 'proper' problem perhaps.
And no its not dangerous in the right place at the right time, it is the emergency brake after all. It can be turned on for a second and as soon as the rear drops let go, no lock no slide no handbrake turn. It does squiddly diddly harm if only done a few times, it does trigger the abs.

If you do it under the threshold where the hydraulic system does the emergency braking then yes it’s severe and dangerous, not something to be advising someone travelling down the road to do.... because under the threshold it’s still the electronic winder acting on the rears only, which is pretty much instant rear wheel lock up.

The emergency braking is via pulling up the handbrake switch and keeping it up until the hydraulic system on all 4 wheels brings the car to a stop, no different to simply driving along a clear road and performing some severe braking on the pedal.


The caliper needs taking off and checking first in my opinion, lining change mode, unbolt caliper body, inspect the 2 slides it runs on, then push back the piston
If everything looks ok assemble back up and spin the wheel with an assistant pressing the pedal/operating the H/B switch to make sure it’s doing the job.

 

[Retroman]

As said already above, that deeper rust is not the superficial stuff that happens overnight in rain - it looks more like the typical, deeper rust on cars sat around on forecourts for months without use. The batteries on such cars can also cause problems as they have sometimes been allowed to completely discharge. If it is isolated to just wheel then I would suspect a fault with the caliper or "slider bolt".

 

[AudiNutta]

Yes existing bracket moved further out

Bracket in the picture of the set below.

Bolted bells £650

Floating set up like below £850

They do a deal when buying both fronts and rears together.

I will be giving them a call when I’m ready to see what they recommend, I believe they offer different cuts in the disc? I won’t be going for drilled again for sure after cracking on the OEM. Also want to discuss the best pads to use, but the ones I’ve got in mind after chatting with you are DS Performance.

Jumping forward to a few posts down to one of yours, am I reading it right that there is an emergency braking procedure accessible by pulling and holding the handbrake lever up?

 

[T-800]

I will be giving them a call when I’m ready to see what they recommend, I believe they offer different cuts in the disc? I won’t be going for drilled again for sure after cracking on the OEM. Also want to discuss the best pads to use, but the ones I’ve got in mind after chatting with you are DS Performance.

Jumping forward to a few posts down to one of yours, am I reading it right that there is an emergency braking procedure accessible by pulling and holding the handbrake lever up?

Slotted curved are great no extra noise.

I’ve recently changed to DS 2500 fronts and they are great, the bedding in procedure needs to be ‘more’ than the instructions suggest though.

The more you use them the better the bite gets.
For £270 they are a bargain as even the DS performance Ferodo pads are £130 a set.

Yes the electronic H/D switch acts as an emergency brake at speed, only over a threshold speed though.

There’s a video of testing it if I remember.

 

[AudiNutta]

Slotted curved are great no extra noise.

I’ve recently changed to DS 2500 fronts and they are great, the bedding in procedure needs to be ‘more’ than the instructions suggest though.

The more you use them the better the bite gets.
For £270 they are a bargain as even the DS performance Ferodo pads are £130 a set.

Yes the electronic H/D switch acts as an emergency brake at speed, only over a threshold speed though.

There’s a video of testing it if I remember.

Great thanks, will go with that then. Then floating and would be good in future if I could just change the rotors and not the bells, but will assess the condition of the bells at the time.

How do you find the DS2500 in comparison to the Performance? Do they give more confidence? Much more brake dust? I’ve been told to be wary of the brake dust, apparently very thick and can damage wheels if not kept on top of. I want the added performance, but I’d rather take a compromise between performance and brake dust if it’s that bad. Not that the standard setup isn’t adequate, had my Dad following me a few weeks ago and a foreign HGV cut across the hatchings in front of me. Was only on the brakes in the RS3 about 60% I’d say and my Dad started off at a good distance but had to get into the hard shoulder in the big old Allroad to make sure he didn’t end up in the back of me. I’ve always been aware of it but not until then did I realise how easily it is to out-brake your average car in a day to day scenario.

 

[Matt2010]

Update: Car back from dealer today. They de-glazed pads + discs and looks much better now.
Brake caliper itself was working fine.

 

[AudiNutta]

Update: Car back from dealer today. They de-glazed pads + discs and looks much better now.
Brake caliper itself was working fine.

Sounds to me like they’ve hidden a problem?? Just removed rust and not asked why it was there in the first place?

Absolutely not a satisfactory outcome.

 

[Gnasher]

Sounds to me like they’ve hidden a problem?? Just removed rust and not asked why it was there in the first place?

Absolutely not a satisfactory outcome.

100% agree - that's like taking it in for an oil leak, them wiping away the oil from the area and then telling you it's not leaking any more.

 

[AudiNutta]

100% agree - that's like taking it in for an oil leak, them wiping away the oil from the area and then telling you it's not leaking any more.

Exactly that! I’d be taking it right back, I’d want them to find a root cause, repair or replace. Not clean the rust off, it’s going to happen again.. clearly the calliper isn’t working.

 

[Matt2010]

They said caliper was ok and pad just glazed over so will see how it goes. It actually got better the more i drove it so think it wasnt used much recently.

 

[T-800]

They said caliper was ok and pad just glazed over so will see how it goes. It actually got better the more i drove it so think it wasnt used much recently.

Your most likely correct.

Audi will have tested that caliper function.

I love how people speculate when they don’t actually know what’s been done

That wheel could’ve been exposed to more moisture than the other side, it happens, seen it on our GTD when it’s been stood in bad weather for a week.
One side very rusty, opposite side (close to a wall so sheltered) hardly any rust.

I’d just monitor it if I was you.