Help please on discs and pads

[Jonesy07]

Really confused here.

Car has just been in to have a warranty fault looked at as I had a warning light come on.

That’s all fixed but they had just called me to say my discs are warped !!

Last service 800 miles ago which was three weeks. Service report to say I have 80% left on my pads and 90% on my discs.

They are telling me its because of one of two reasons :
1. The hub is out of line and not covered under my Audi warranty ( Maybe due to my 8mm spacers )
2. They have just worn down due to excesses heat and use ( what in 3 weeks from 90% ! )

Cost to replace both £1238 !!

Help as I did not see this coming…

[PetrolDave]

They have just worn down due to excesses heat and use ( what in 3 weeks from 90% ! )

Get a second opinion, either the original report of 90% left or this new diagnosis was/is b*ll*cks .

[adsgreen]

Agree with the above - cant wear them that fast!
Exactly how would spacers cause a floating disc to warp?

One thing to consider is that it doesn't matter how new discs are they can still warp. I had a brand new car suffer warped discs within 1200 miles.

Also it may be pad material build up causing the same symptoms which if so you should try to get skimmed - at least with 90% material left it should have plenty of meat on it to skim.

[P_G]

Buy a Vernier Cailper from Halfords and measure them yourself. Min thickness is 32mm, unused 34mm. If anytning over 32.5mm get them skimmed if they are 'warped', more likely heat highspots but no need for new discs. Very rare for the hub to be out of line. What pads are on, OEM?

[adsgreen]

Oh - did the same place that say te discs are warpe do the service?
Either way a second opinion definitely required.

You can test this easy enough yourself.
For fronts drive on the motorway at 70ish and slowly apply light brakin until nearly touching the discs. If warped or pad buildup you'll feel a distinct wobble in the steering wheel. It'll also stop wobbling when you come off the brakes. For the tears do the same but carefully raise the handbrake and you'll feel it pulsate. Prob best soon at slower speeds - don't want to slam the handbrake on!

[Jonesy07]

Right.. same place as the service.

And yes a wobble at 70 when breaking, so i had thought that i may have a problem before it went in.

Pads are OEM. they have suggested it was down to heat.

Never had any skimmed before, any idea on cost ?

They are investigating further tomorrow and coming back to me.....

[adsgreen]

What kind of use does the car get (town vs motorway)?
how hard are you on the brakes?

[Timster]

Before you go and spend more money.... there is some simple things that CAN cause your discs to warp (it's actually the hub part, but heh)...
And thats.... over tightening of the wheel bolts.
Has anybody used an air gun on your wheels lately ??

Also,try this: Remove all your spacers and refit wheels with original bolts (assuming you've still got them).
Ensure the bolts are NOT done up beyond spec (which I think is 120.. but check)

Finally... check whether the ventilation holes on your discs are clear of brake-dust/muck. If they're clogged, the disks can overheat.
Simply drill out with the wheels off. (quite boring but doesn't take too long)

[Jonesy07]

What kind of use does the car get (town vs motorway)?
how hard are you on the brakes?

It does 30 miles a day on the motorway that's all. Never heavy on them.

[adsgreen]

What kind of use does the car get (town vs motorway)?
how hard are you on the brakes?

It does 30 miles a day on the motorway that's all. Never heavy on them.

Being to light on them can be the problem... The brakes are massive and quite overspecc'd for road use.
As such it only takes a slight pressure on the pedal to slow down. This means only the highest parts of the disc make contact and get hot. A braking is a function of the material transferring to the disc which happens only when hot. So the high spots get higher and the problem is self producing at that point. If you press a little harder then the whole pad is in contact and material is evenly transferred.

Anyway - not much help now I know but it means that a skim should fix it.
If you catch it early enough you can recover the disc by doing several very hard non abs stops to really heat everything up and try to redistribute the pad material.

Then it's a case of not being to light on the brakes and using the handbrake to hold the car when stopped.

[Timster]

Erm ... am I invisible ??

[Jonesy07]

Before you go and spend more money.... there is some simple things that CAN cause your discs to warp (it's actually the hub part, but heh)...
And thats.... over tightening of the wheel bolts.
Has anybody used an air gun on your wheels lately ??

Also,try this: Remove all your spacers and refit wheels with original bolts (assuming you've still got them).
Ensure the bolts are NOT done up beyond spec (which I think is 120.. but check)

Finally... check whether the ventilation holes on your discs are clear of brake-dust/muck. If they're clogged, the disks can overheat.
Simply drill out with the wheels off. (quite boring but doesn't take too long)

The wheels have been refurbed in the last few months so I can check this but I guess the wheels are off by now.

Does anyone know the skimming cost ? Cheers

[scottie1979]

Im agree with Timster
I have recently fitted spacers and, perhaps pure coincidence, now have what i first assumed was warped discs. Since reading that thread regarding spacers a while back i have a sneaking suspicion that this might just be the cause.
I think i have the spacers that leave the small gap as mentioned in that thread. I havent been driving the car lately as ive been away so i still need to check all this out.
Worth a half hour of your time before forking out. I assume by the options they gave you they felt the problem on the test drive and didnt inspect?

[adsgreen]

Erm ... am I invisible ??

No. You offered a possible solution based on your experience, as did I.

[P_G]

Skimming should cost anywhwere between £50 to £100 for both discs. I had similar issues with high motorway use and in the longer term changed to EBC Yellowstuff pads and have not had the issues as often (was juddering ever 1k miles now only once in the last 30k)

Check with spacers off first, then check wheels are true but juddering at 70 does sound like heat spots on the discs.