16 month old Q7 discs warping?

[MKM_06]

Hi all,

I have a Jan '17 Q7 and it's done about 10k miles - we went away for three weeks and the car was left on the drive. When we came back there was some fairly serious brake judder going on. My dealer has inspected the discs and has said that the front pair of discs are warped - runout of 6mm (not quite sure what that means?). Because it's a 'wear' issue, it's apparently not covered by warranty so they've quoted about £1k for discs and pads.

Has anyone else heard of whether the discs are prone to warping? The dealer is suggesting that it is due to excessive heat as a result of heavy breaking, but this is just the family runabout and I've not exactly been driving a Q7 like an RS4!! Any thoughts/comments appreciated, it seems really odd that they can just warp like that and it not be a warranty issue!

[bill.wj.wilson]

That's a crazy amount of money for both parts and labour, get a quote from a decent garage should be less than half that. Audi don't make brake discs or pads so any decent make would suffice.

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[Andymcdonald]

That's a crazy amount of money for both parts and labour, get a quote from a decent garage should be less than half that. Audi don't make brake discs or pads so any decent make would suffice.

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You can use a Bosch service centre.


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[Gyro]

I've got quite a heavy right foot in my SQ7 and could be called "heavy" on the brakes at times and I've got no issues at almost 20,000 miles. Car was serviced a couple of months ago and the paperwork for the health check they do had a big green tick next to the brakes section. I would seek a second opinion from an indy if I was you, and / or push like crazy to get Audi to foot the bill - have they sent you a video of the discs? Seems to be the thing now when they find something - I got a video and bill for £1,600 for a new wheel and tyre after a pot hole incident; I took the car to the Wheel Specialist and got the wheel fixed and a new tyre through my Premia wheel/tyre insurance...and in total it cost me the excess of £10!

I can't see how the brakes would magically become warped after sitting still for three weeks? Just on that, not driving it for three weeks may have allowed some crud and possibly a little bit of corrosion to build up on the discs - I get this on my Passat as it does 90% motorway miles then sits on my drive for days on end, after a few miles of driving it goes away, but it doesn't sound as if it's nearly as bad as what you're experiencing.

Let us know how you get on, good luck.

[FortyPlus]

Hi
interesting! I had repeated, shocking misdiagnosis of brake judder issues by reputable Audi/ VW garages on my previous VW Phaeton. I drove it fast but smoothly so little if any hard brake use. In summary I had discs replaced under warranty (twice) due to vibration issues. The issue reappeared, so I did some internet hunting.

As I recall, brake pad material interacts with disc surface and can be "patchy" depending on bed-in process.

To solve my problem the solution was simple. Get an empty road (or better a private road) and from 100kph brake aggressively but not engaging ABS to almost standstill. It's important not to come to a standstill. Do this until the brakes are HOT. In my case I could smell the pads. I went for a drive to cool things down with very light brake application.

It sounds a bit crazy, but this solved the problem permanently. It appeared my smooth driving style did not facilitate a proper bedding in by the pads/ discs. I had explicitly raised this issue with VW and they dismissed this as being impossible.
Do some internet googling and there are some youtube videos on this also

Phaeton is somewhat similar to Q7: AWD/ 3L V6/ 2000Kg so brakes are pretty big to match. High consumption of brake components is not inevitable on a heavy car. It's all about driving style. I did years of "motorway" speed driving on a 2000kg Phaeton but wafted around town: pads typically lasted 40,000 miles.

It's worth a try. You have nothing to lose.

EDIT
I just re read the original post. Runout is the deviation from "flat": obviously a perfect brake disc will be perfectly flat. 6mm of runout I would think is impossible. I do not think the disc would pass through the pad gap with 6mm runnout. Maybe 0.6mm?

The article below on brake function is one of those I viewed when I had my problems: very useful and in my experience accurate.

[Gazwould]

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

[Andymcdonald]

I had an A6 c7 which was a demo and had been on the forecourt for a few weeks. I started to feel a light vibration under braking and had a master tech to a drive with me.

He stated that the new wheels don’t offer as much weather protection so rust is a bigger factor than years gone by. When you leave the car the surface rust can, not always cause intermittent wear which can result in what appears to be warping.

This doesn’t seem right and I think a letter to Audi is in order

Andy


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[MKM_06]

Thanks all, they showed me the Audi cam and you can see the needle moving as the rotor is turned, so I suspect it isn't just corrosion, but really surprised at the 'extreme heat' argument for warping. Surely the discs are designed for this type of car and have over engineering built in? I do think following this up with Audi is worth it though - even with a third party garage I'll be looking at several hundred quid for the whole job, which I really feel should be a warranty issue.

[FortyPlus]

Can you see how much the meter deviates. I went to the bother of getting a run-out meter when I had problems, and I discovered that no disc is perfect. Some of the BS technicians feed back is sad. My experience is everything must be solved by "replacing the part".

[MKM_06]

In the AudiCam video you can see that the needle travels between positive 2 and negative 4 on the little dial. I've just read in depth through that article that Gazwould has posted and it seems to make sense to me. I might well try as the article and FortyPlus have suggested and see if that makes any difference. It will save me a fair amount of money if it works, what have I got to lose!

[Andymcdonald]

In the AudiCam video you can see that the needle travels between positive 2 and negative 4 on the little dial. I've just read in depth through that article that Gazwould has posted and it seems to make sense to me. I might well try as the article and FortyPlus have suggested and see if that makes any difference. It will save me a fair amount of money if it works, what have I got to lose!

Probably thousandths ?


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[gmchan]

I get lots of shudder on mine after using the ACC for any period of time where there are long downhill stretches. It seems to either be overheating or pad material build up. A few very heavy applications from speed seems to clear it up.

[vwcabriolet1971]

It would be useful to know what the divisions on the dial indicator were. Most engineering metric indicators have 0.01mm divisions .If this type of indicator was used then 2 positive divisions and 4 negative indicates a total run out of 0.06mm which is not a lot and would not cause any braking problems. We need to the know the actual indicator scale to form any opinion on the runout. This value is normally on the instrument dial.

[Rob69]

Old post by the OP so maybe resolved by now, but when they have the dial gauge on the disc face I'm presuming the road wheel is removed - have they bolted the disc back onto the hub with the wheel bolts and washers or are they just relying on the small set screw to hold the disc in place. If the disc is not bolted back onto the hub then the run out could be due to it just being loose against the hub.

[vwcabriolet1971]

Old post by the OP so maybe resolved by now, but when they have the dial gauge on the disc face I'm presuming the road wheel is removed - have they bolted the disc back onto the hub with the wheel bolts and washers or are they just relying on the small set screw to hold the disc in place. If the disc is not bolted back onto the hub then the run out could be due to it just being loose against the hub.
It's difficult to prevent some small movement to disc / suspension when hand turning the disc which causes the indicator needle to move.

[Mark 2805]

As a follow on from this- my Mar 1st 2018 Q7 ( 3000 miles) has been at the dealers today as i was getting vibration from rear brakes. Master tech came out on test drive with me to confirm issue. Have just had a call from them that they have found issues with rear disc on one side which is out of tolerance. As such rear discs and pads being replaced. Seems like Audi are having some issues with Q7 brakes in general. Looking at AudiWorld it looks like a Technical bulletin has been issued about squeaky front brakes. New pads etc are being fitted across the pond. Perhaps Audi UK might be aware?

[MKM_06]

Thanks for all the comments folks - having squinted at the Audi cam footage it appears that each division on the dial is 0.01mm, however, the advisory report that they provided with the inspection states 6mm deviation! I did the extreme braking tests as mentioned further up the post and this has significantly reduced the shudder, I would suggest it has gone but my wife remains not 100% convinced! Either way while we wait to hear what Audi have to say it's significantly improved drivability, so thanks to all that suggested. Will wait to hear what Audi say but not likely to pay out £1000 for this out of my own pocket!

[FortyPlus]

Good to hear you are making progress;)

Service Department does not inspire confidence:-( does any?

[Mark 2805]

An update- 6k miles onto new set of discs and pads vibration has returned in the rear. Back into dealers, same master tech confirms run out on discs is out of tolerance. Service Mgr says possibly caused by excessive heat it brakes. I have never been hard on brakes, indeed this is my 7th Audi and never had issues with discs or pads before. Indeed had a A4 on 120k miles still on first set of pads and discs. What is becoming apparent ( based on threads here and on Audi World) is Audi are deaf having issues with Q7 brakes. This is a powerful car so should have a degree of over engineering built in. 6 k on a set of pads and discs before issues start to creep in is ridiculous. Aside from brakes it has been a great car thus far, my fear is that longer term it is going to need a new set every year ( based on average driving). Previous audi's have certainly done the lease period without the requirement. I get this is a heavier car but not excessively more than the A6 Allroad i traded in. that had 60k on it and still plenty on pads all round. Lets hope Audi is looking in to alternative providers of discs and pads.