Brake Problems

[Owyn]

Hi all,
I've got a single turbo 2015 allroad (272), its always suffered with brake judder, about a year ago I changed all the discs and pads which cured it for a short while but it came back. I can't feel the judder through the steering wheel but through the car, a bit like a disc has a grippy bit on it.
I have just done the rear discs and pads again as I figured the lack of steering feedback pointd me to the rears but the judder is still there.
My next job is a runout check on the front discs-then it'll be new discs and pads.

The question I have is it worth getting hold of some BiTDI/A8 brakes with the bigger discs? What are peoples experience with them? They look like an easy swap and the bigger disc/pad may help with heat disipation. It always seemed a bit strange that the similar BiTDI (granted a bit faster) got bigger brakes-it makes me think the 245mm single pot brakes on mine are up against a design limit.

Thanks

 

[RAF_S7]

I would have the wheels and suspension checked to make sure there’s not a problem with those, before sinking further money into the brakes…..

John

 

[Owyn]

I would have the wheels and suspension checked to make sure there’s not a problem with those, before sinking further money into the brakes…..

John

Thanks, thats a great shout, the bushes etc. are all in pretty good nick, the only question mark I have is that it has a non genuine front upright on one side which makes me wonder about hub runout. I can check that.

As for the wheel then its only when on the brakes that there is any judder, it also does it at slow speed (5mph ish).

Weirdly, I had the same issue on my old B8 A4, I wonder if its something to do with how I drive it!

 

[RAF_S7]

Thanks, thats a great shout, the bushes etc. are all in pretty good nick, the only question mark I have is that it has a non genuine front upright on one side which makes me wonder about hub runout. I can check that.

As for the wheel then its only when on the brakes that there is any judder, it also does it at slow speed (5mph ish).

Weirdly, I had the same issue on my old B8 A4, I wonder if its something to do with how I drive it!

Well unless you’ve had a hard knock you could have a buckled wheel?

 

[NHN]

Also check piston movement.

 

[Owyn]

Thanks both,
I've just checked runout on the front, .05mm and I've read anything less than .08mm is good.
I did notice the big bush on the rear, lower arm seems pretty floppy on both sides, no knocking or split rubber tho, I'm guessing with the size of it that it's meant to have some movement.
I'll check the wheels and move onto the rears next, calipers is a good shout, thanks.

 

[19ryanh93]

Thanks both,
I've just checked runout on the front, .05mm and I've read anything less than .08mm is good.
I did notice the big bush on the rear, lower arm seems pretty floppy on both sides, no knocking or split rubber tho, I'm guessing with the size of it that it's meant to have some movement.
I'll check the wheels and move onto the rears next, calipers is a good shout, thanks.

Did you ever solve this? Yeah he got the same on my 2015 Avant.

Cheers


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[Owyn]

Did you ever solve this? Yeah he got the same on my 2015 Avant.

Cheers


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I've not solved it yet, new rear discs and pads seem to have helped a bit, I've done a runout check on the fronts and they were in spec, I'm going to do the same on the rear when I get half a chance, hopefully that will point to something!

 

[19ryanh93]

I've not solved it yet, new rear discs and pads seem to have helped a bit, I've done a runout check on the fronts and they were in spec, I'm going to do the same on the rear when I get half a chance, hopefully that will point to something!

I’ve done front and rears and swapped discs and pads but still getting shaken to bits and struggling to work out what it is.

Mines a 272 aswell.


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[NHN]

Check for bush etc wear as if it was instant shaking on new brakes, it can't be those.

Warp discs aren't instant unless you're tracking immediately after & braking at silly speeds so heat dissipation is at it's worse unless air directed to cool things whilst in use like rs cars.

 

[19ryanh93]

Check for bush etc wear as if it was instant shaking on new brakes, it can't be those.

Warp discs aren't instant unless you're tracking immediately after & braking at silly speeds so heat dissipation is at it's worse unless air directed to cool things whilst in use like rs cars.

While it was up in the air had a look and the lower rear inner bush was starting to crack but wasn’t moving and wasn’t gone. No knocks when driving round either.

It’s stumped everyone I’ve asked so far


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[Owyn]

While it was up in the air had a look and the lower rear inner bush was starting to crack but wasn’t moving and wasn’t gone. No knocks when driving round either.

It’s stumped everyone I’ve asked so far


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thats really interesting, the lower, rear, inner bush on the front wheels is really floppy, I think that they are meant to be like that but am not sure.
The bush looks intact but that may be something to look at.

 

[NHN]

Remove pads & check piston in out movement, making sure not to wind the pistons out completely by fitting a block or something to block fully out position or that's another pain to do.

 

[J10NMM]

any joy?

 

[Owyn]

Not sorted it yet, still juddering, I've got a set of old A8 brakes (like the bitdi) to fit when I get round to it. I'm hoping it's a front disc problem. Then I'll probs do all the front suspension arms, then it'll be time to get a new car probably.