Warped Discs or calliper issue?

[yellowplum]

Ok, so I have another seemingly irritating problem that has reared it's ugly head. When I brake it seems to 'judder' slightly, or like you are getting a small vibration through the steering wheel, also like the brakes are biting then not and then biting, but very quickly.

The discs and pads have been on the car since around mid 2013 when I replaced both front and back all round. It started around a month ago and the only thing I can deduce is that either I have warped the discs on the front or maybe the slider isn't doing exactly what it should be doing and has also heated and warped them.

The other thing I noticed is that my fuel consumption seems to be up, not sure how accurate the onboard computer is for telling you this but I am only getting around 40-44mpg when I was getting 44-48mpg

Firstly, can you even tell if you have warped the discs, and how? Second it may be worth stripping the sliders and run some grease along them.

[chelspeed]

> Firstly, can you even tell if you have warped the discs, and how?

When you brake it seems to 'judder' slightly and you get a small vibration through the brake pedal.

Definitive test is to take the wheel off and us e a clock gauge (DTI) to check for run out.
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I don't think lubricating the sliders on the calipers will help this.

[yellowplum]

I haven't managed to be able to through the gauge on to the car, but to be honest they will need replacing anyway so going to replace them. I was told to check for play in the bearing to see as that could also cause issue, or they haven't been mounted correctly or they have moved and caused the issue.

I have ordered another set of DS2500 pads but will not be going for the ATE brake discs again, they don't seem to be that great.

Debating actually wether to go with OE ones or get some Brembo ones or even Ferodo. I am tempted to get a set of Brembo Max ones since they are they same price as the OE

Does anyone know what the OE ones actually are? I heard they are Brembo.

[C00kie]

Juddering through the brake pedal and steering wheel definitely sounds like warped discs to me. Happened to me on an old Astra - had the front discs replaced and then same thing happened again within a year, took it back to the garage and they replaced them FOC. So it may be the case that you can get poor quality batches.

I'm just about to change all discs and pads on my 2.0 TSi - going to go for Tarox G88 discs and Strada pads on the front, Bosch pads and discs on the rear (bog standard but should be decent quality being Bosch). I don't know what the OEM kit would be.

[yellowplum]

Definitely through the steering wheel not so thought the pedal, you just feel the bite let go bite let go through the pedal. Interesting conversation with Ferodo who said that it was something called DTV. Though my only concern is what is causing DVT.

Driving today was strange, maybe I am just listening to every noise going, around 50MPH I get noise in the cabin which is a low humming/buzzing style noise, if you go faster it stays but not as loud, lower speeds you don't really hear it.

[Cuprabob]

The noise you describe is like what you get when you get sawtooth / treadstepping wear on the tyres. Very common on the rear tyres of VAG cars, including the Scirocco.

[yellowplum]

Interesting, ok so I'll replace the front brakes and discs, I think I will stick with the DS2500 pads and just keep the Ferodo discs that got delivered for the moment, see how that goes.

As with regards to the tyres, I have the winters at the moment as the alloys are being refurbished. So we shall see if they are any different when I change them round in the next week or so.

[C00kie]

I had the same humming coming from the rear of mine when I first got it...right about 50mph as you say. Thought it was the bearings so checked them but all was ok. Turned out it was the tyres - they weren't worn to look at but were old and starting to crack on the sidewalls.

[yellowplum]

Funny thing is the wheels got refurbished last year, I posted a pic somewhere on here of them. However the mat coating didn't take and started to peal off last month. So when I showed it to them they agreed to have all redone. Moreover the wheels I had on where the K1 Pirellis on the back but a set of Hankook tyres on the front. Around October I was travelling on the M25 towards the M20 which is concrete motorway and by god the noise in the cabin was unbearable. Seriously I have never heard anything like it before, you couldn't even hear the radio.

Hence this time of got some Pirellis again and chucking the Hankooks, never again!

[yellowplum]

It was the rear bearing completely gone. Changed that one, the other was changed after 3 years under warranty according to the dealer. Not the best at lasting it seems.

Although changed the brakes and pads on the front also to deal with the judder Drove around 2000 miles over Continental Europe last week and found that the judder is creeping in. Either it's my paranoia or there is something else on the front. Maybe the calliper, bearing or just the pads are downright rubbish.

[Viking]

Some interesting detail here regarding DTV, and also other causes of brake judder.

http://www.apecbraking.co.uk/brakejudder" onclick="window.open(this.href);return false;

Just for info, I fit APEC brakes all the time and have no issues. Excellent quality from a virtually unknown (for some reason) brand