Discs - to replace or not to replace?

[charlie_moo]

Hi All,

I became a member when I bought my RS6 PE back in May 2020, and have found the forum extremely useful, so massive thanks for all your contributions!

Here is the obligatory pic of my P&J

My brake pad warning light came on recently (I was aware they needed changing as they were at 70% worn at the last service). I have bought front and rear OEM pads from Audi Parts Direct, which will be fitted by 4 Rings in Dartford. The big question I am procrastinating over is 'do I change the discs at the same time?'

My car has done 32k miles I assume on the original discs and pads. I usually get two pad sets to each disc, and in my experience discs have lasted longer than 32k miles.

I've attached some pics of my discs. I would say the lip is around 0.8-1mm (probably more pronounced on the inside edges) and there is some noticeable corrosion (which flakes off when rubbed). But I'm not getting any judder or squeal and the wear dimples are still visible.

Front

Rear

It would be much appreciated if anyone can share their thoughts / experiences on changing their own discs. How long generally have they lasted? What state where they in when you changed them? Better or worse than mine?! I've got a quote from Tom Fox at Crewe Audi for the discs - just trying to either justify the cash or convince myself there's no need to cough up just yet!

Many thanks, Charlie

[JoolsBerko]

Hiya I'm no expert but if no judder, I'd say just change the pads. Happy to be corrected by those far more knowledgeable than myself - but when I had my TTRS previously, when I did start feeling the pads to be on the way out, I asked the same question to the garage I use, and they said as there was no judder, no need to think about the discs. And in the time I kept the TTRS after the pad changes, no issues with the discs. FYI - I used my TTRS as a daily driver but never "thrashing it" or needing to "work the brakes", and I use the RS6 as a daily (albeit I get to work from home a lot so it's only done 1k miles in the 6 months I've had it) and again I treat it very gently (mainly to prevent the potential for additional running costs that I can avoid).

[charlie_moo]

Many thanks for your reply Jools. My driving patterns/habits are similar to yours. When 4 Rings (local Audi specialist) had a look they recommended changing the discs but said it wasn’t essential for a while yet. I’m just a bit concerned about the corrosion (probably due to the lack of use over the pandemic) and whether the new pads will bed ok with the worn discs.

[noidea]

I would measure the thickness. I would say they are close to being on the minimum.
I changed my front discs and pads at the weekend (B8 RS4) and I waited for the light to come on.
This is the 2nd time I have done them, 1st time at 30k and 2nd at 61k so fairly consistent. The discs were below minimum thickness and that is with one set of pads.
There is only 0.8mm per face on the discs. The pads had about 3-4mm left.
As the front pads are reasonably expensive and you will probably be changing the discs well before the pads are worn out, I would just bite the bullet and change the lot.

Also I would try to keep the holes clear too as this can cause issues with vibration.

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[charlie_moo]

Thanks for sharing your experience with your RS4, and for the sound advice.
I think you’re right about the discs getting close to minimum as I have since read in another post the difference between full thickness and min thickness on these discs is 1.6mm, so with mine being ~0.8 worn on one side I must be close to this. I think I am edging towards biting the bullet. I’m just not sure how much longer I plan to keep the car. But I guess even if I sell next year, nearly new discs will be a big selling point.

[wildbore]

I drive like a saint - with the wife in the car, which she usually is on most journeys, there is no room for hard braking (apparently it hurts her neck...), and it's mostly motorways, anyway. Point is that I still needed new discs when the pads wore out at about 30K miles. With the absence of asbestos in pads, they are more wearing on discs nowadays and the consumption rate is no longer such that a disc will see off several pairs of pads.

Of course, the thickness measurement is the only rule you need to apply here; I am just saying: don't expect your discs to outlast your pads - certainly not on these big, heavy bruisers.

[charlie_moo]

Ha! Ditto... I usually get a punch in the thigh if I accelerate or brake too hard! Really good to know the experience of a someone with similar driving patterns. Thanks mate

[innercry666]

My pennies worth. If you are on original discs at 32K miles and you deffo need to do pads I would personally do the discs at the same time...

[charlie_moo]

Really appreciate the reply! Given the consensus I think I'm going to cough up for the discs. About to put 4 new PS4S tyres on too, so it's proving to be an expensive week! Will get the wheel alignment sorted at same time, and with the new pads and discs, the car should be sweet once all complete. Now need to research how best to bed in the new brakes...

[ko2302]

just curious, how much is non-ceramic 4x discs and 4x pads including installation?

[charlie_moo]

I was quoted 2600 by main dealer. But it's costing me around 2100 all in (buying OEM parts online and having an independent Audi specialist fit them)

[innercry666]

How much did Tom quote you for front discs?

[charlie_moo]

880 fronts, 725 rears, 30 delivery

[114uyc]

Keep an eye on https://www.blackcircles.com/ they often have 15% off, deals only last a day so keep checking. Normally see them twice a week

[charlie_moo]

Thanks for that. I actually got the 15% off deal from Kwik-Fit in the end. Worked out 250 per tyre (fitted). They're offering the deal until end of Nov, but you only get 15% off if you buy four. Was slightly nervous about using them, but my local branch has half decent reviews and they seem to have done a good job. I'm getting the wheel alignment sorted elsewhere though.