Wavy disc wear

[murph7355]

Do the pads on the B8 contact the whole of the wavy surface?

Or if a car's been sat a while is it normal for the crests of the wavy bits to go rusty...?

[Foxy]

I think the rust is normal (mine do after a lay up). I was told that if the wavy discs are very hot after a thrash, be careful not to rest your foot on the brake when you come to a stop as it can create hot spots on the disc. I use hill hold and presume it acts like a handbrake, i.e. not pad on disc.

[RossDagley]

Yes pads contact the whole part of the wave. Rust should be removed on a few turns of the wheels with brakes applied

[Rallyz]

Foxy, I think you'll find that hill hold applies the normal (footbrake) pads when the engine is running, although when you turn the engine off, the handbrake comes on by default if hill hold is set - you can hear the actuator pull it on.

[geoffdunk]

Foxy, I think you'll find that hill hold applies the normal (footbrake) pads when the engine is running, although when you turn the engine off, the handbrake comes on by default if hill hold is set - you can hear the actuator pull it on.

Yep, in traffic it applies the foot brake system, and when switch off it applies handbrake system. I love HHA, and i ,love how it remembers the setting unlike older Audi's, mine never gets switched off.

[Surrey Sam]

Hill Hold Assist (HHA) locks the brake line pressure at the point of stopping, so all four corners will be in contact with the discs. The handbrake is done by the rear pads only and is via a different mechanical circuit.

murph7355 - Can you post a picture, as what you describe doesn't sound normal to be honest, If mine rust from being left/exposed to damp, then it'll be over the whole disc face.

[murph7355]

...
murph7355 - Can you post a picture, as what you describe doesn't sound normal to be honest, If mine rust from being left/exposed to damp, then it'll be over the whole disc face.

Here you go...what you are saying about yours is what I'd have expected.

[Surrey Sam]

Yes, that's not normal.

[Surrey Sam]

If you look under the car, is it also the same for the inside face?

[murph7355]

It's not my car so don't know

Am currently contemplating moving from my B7 to a B8...this car is the spec I would like. But there are warning bells ringing (also see thread on DRC ).

1 owner car too, so surprised these things are there - VATQ so a company car driver not looking after it maybe? Knowing the price of brakes and fixing DRC I'm getting tinnitus . It's 150 miles away so not a straightforward pop and see.

The disc on the other side doesn't look as bad. It looks like the pad is only touching the disc with its centre to me...or maybe the disc was worn unevenly ahead of new pads.

But....

[Surrey Sam]

Yeah, a few alarm bells there then. What sort of mileage?

It could be something like cheap pattern pads just chucked on the car, poorly skimmed discs or the calliper pad carrier plates expanding from galvanic corrosion and pinching the pads. Any way you look at it, there is something there that requires further inspection to rectify.

[murph7355]

45k miles.

Worst case - new front pads/discs and 2x dampers maybe. £2.5k?

But then what else hasn't been kept on top of.

What I really ought to do is stop looking at Autotrader

[Surrey Sam]

Ok, think I know the advertised car now - Sepang one in Bristol?

If that is the one, then I think it might be a worn disc cover up and the lips have just been skimmed off? There is only a slight concern from seeing the acid stained wheel nut caps, that the problem could be galvanic corrosion on the callipers instead. As this could happen from regular wheel acid application splashed onto the callipers which expedites the rate of corrosion, but I reckon the cover up by skimming is more likely. A service history check with the servicing dealerships would see if the discs have ever been changed.

The investigator in me also thinks that it has got a retro fitted black optics look. Reason for saying is that the window surrounds should actually match the roof rails and be a matt/satin colour and not gloss coloured which is for the grille only. So I reckon it's had an aftermarket eBay grille (because OEM are £1200), gloss black sprayed window trims and perhaps 2nd hand A4 Avant roof rails fitted which are a satin colour. As that'd be the cheapest way for a dealer to get a black optic look on the car. Other than that, it's a MY14 car with a good spec which is certainly not easy to find.

Front discs and pads could be purchased for around £1100, although I'd want to see what state the rears are in as well. They might not be far away from replacement as well, so cost could quickly go through £2k? As for the DRC, that's a tough one, advert says the car has a 2 year 60k Audi warranty. So if correct, any failure should be covered by that.

[Surrey Sam]

^^^ Actually I might be wrong on the optics? Windows might be gloss on the B8?

[murph7355]

Audi warranty is an error in the text.

I asked if there was evidence of the brakes being changed and was told not. Doesn't mean to say they haven't been, but I think 45k is a stretch on an RS4.