A3 8V Rear Carrier Bracket Bolts

[JontyMort]

I’m doing the prep for the rear brakes on my 66-plate 1.4 TFSI. I’ve proved I can slacken the slide pin bolts (7mm Allen key, but there’s no room to get a ratchet on - thanks, Audi). I’ve proved - after a serious amount of grunting and swearing - that the 14M triple square socket head bolts can be slackened (everything prevents access to everything else - thanks again, Audi). And I‘ve got an OBD tool for the electronic handbrake. So… can anyone confirm the part number for the carrier bolts, and the torque wrench setting? I’ve seen N911 689 01 as the part number, and a torque setting of 196Nm. Is that correct?
Finally, having put the EPB into pad change mode, is the piston retraction a straight push, or does one have to twist also?

 

[8YARWY]

I’m doing the prep for the rear brakes on my 66-plate 1.4 TFSI. I’ve proved I can slacken the slide pin bolts (7mm Allen key, but there’s no room to get a ratchet on - thanks, Audi). I’ve proved - after a serious amount of grunting and swearing - that the 14M triple square socket head bolts can be slackened (everything prevents access to everything else - thanks again, Audi). And I‘ve got an OBD tool for the electronic handbrake. So… can anyone confirm the part number for the carrier bolts, and the torque wrench setting? I’ve seen N911 689 01 as the part number, and a torque setting of 196Nm. Is that correct?
Finally, having put the EPB into pad change mode, is the piston retraction a straight push, or does one have to twist also?

Piston once in pad lining change mode just needs pushing back.
Slacken top cap of reservoir off too.

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[JontyMort]

Piston once in pad lining change mode just needs pushing back.
Slacken top cap of reservoir off too.

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Many thanks. I hadn’t forgotten the reservoir - in practice will remove some fluid with a syringe too. Fronts already done, so will do a fluid change after sorting the rears, and that should be fine for two years.
Strangely, the fronts have lasted twice as long as the rears - despite doing all the work. I suppose the rears get all the crud thrown up by the front wheels.

 

[JontyMort]

A dry but not too hot Bank Holiday gave a perfect opportunity to get the job done. If anyone is interested in a diy, with the solid 272mm diameter rear discs you definitely do need to remove the carrier bracket. That is the only really difficult part - removing the caliper from the bracket and, especially, re-fitting is merely a bit fiddly. Putting the caliper handbrake mechanism into service mode is very easy with a diagnostic tool. I got an Ancel VD500, and it works well at a good price.
Slackening the carrier bracket bolts is certainly not for the faint-hearted. A pit or lift would make it a lot easier. I have a pair of Rhino ramps and stuck the rear wheels up on them. It may seem odd to start work with the wheels on, but I hate wrestling with high-torque bolts with the car on stands or a jack. With the extra height you can get a decent bar on the bolts - and in the end my trusty 3/4” square drive with 1/2” adapter did the trick.

 

[AJB]

A dry but not too hot Bank Holiday gave a perfect opportunity to get the job done. If anyone is interested in a diy, with the solid 272mm diameter rear discs you definitely do need to remove the carrier bracket. That is the only really difficult part - removing the caliper from the bracket and, especially, re-fitting is merely a bit fiddly. Putting the caliper handbrake mechanism into service mode is very easy with a diagnostic tool. I got an Ancel VD500, and it works well at a good price.
Slackening the carrier bracket bolts is certainly not for the faint-hearted. A pit or lift would make it a lot easier. I have a pair of Rhino ramps and stuck the rear wheels up on them. It may seem odd to start work with the wheels on, but I hate wrestling with high-torque bolts with the car on stands or a jack. With the extra height you can get a decent bar on the bolts - and in the end my trusty 3/4” square drive with 1/2” adapter did the trick.

Thanks for that - really useful info. Mine's still on its original brakes, but I'm sure I'll have do to them at some point! On my wife's old R52 MINI you could get the rear discs off without removing the caliper carrier, so good to know I'll need new bolts in advance for the A3. Stretch bolts are tedious for that!!

What was the answer to your original question of whether the pistons just push back or need rotating, once you've retracted the handbrake motors?

 

[JontyMort]

Thanks for that - really useful info. Mine's still on its original brakes, but I'm sure I'll have do to them at some point! On my wife's old R52 MINI you could get the rear discs off without removing the caliper carrier, so good to know I'll need new bolts in advance for the A3. Stretch bolts are tedious for that!!

What was the answer to your original question of whether the pistons just push back or need rotating, once you've retracted the handbrake motors?

On the versions with EPB, it’s a straightforward push back on the piston. That’s logical when you think about it - the retraction using the OBD gizmo takes the place of the twisting on the manual-handbrake calipers to reset the mechanism. To be fair, it‘s an improvement.
Just looking at my Haynes manual for my first ever Audi (a 1986 100), I recall this was always a PITA. In theory you screwed the piston in with an Allen key. But obviously in real life the hexagonal slot in the piston had rusted out. Exchange refurbished calipers saved a lot of hassle, at a price.
I haven’t actually fitted the new stretch bolts yet. I re-fitted the old ones as a temporary measure, as I was waiting for the new ones to arrive. A job for this coming weekend.

 

[george forbes]

A dry but not too hot Bank Holiday gave a perfect opportunity to get the job done. If anyone is interested in a diy, with the solid 272mm diameter rear discs you definitely do need to remove the carrier bracket. That is the only really difficult part - removing the caliper from the bracket and, especially, re-fitting is merely a bit fiddly. Putting the caliper handbrake mechanism into service mode is very easy with a diagnostic tool. I got an Ancel VD500, and it works well at a good price.
Slackening the carrier bracket bolts is certainly not for the faint-hearted. A pit or lift would make it a lot easier. I have a pair of Rhino ramps and stuck the rear wheels up on them. It may seem odd to start work with the wheels on, but I hate wrestling with high-torque bolts with the car on stands or a jack. With the extra height you can get a decent bar on the bolts - and in the end my trusty 3/4” square drive with 1/2” adapter did the trick.

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A dry but not too hot Bank Holiday gave a perfect opportunity to get the job done. If anyone is interested in a diy, with the solid 272mm diameter rear discs you definitely do need to remove the carrier bracket. That is the only really difficult part - removing the caliper from the bracket and, especially, re-fitting is merely a bit fiddly. Putting the caliper handbrake mechanism into service mode is very easy with a diagnostic tool. I got an Ancel VD500, and it works well at a good price.
Slackening the carrier bracket bolts is certainly not for the faint-hearted. A pit or lift would make it a lot easier. I have a pair of Rhino ramps and stuck the rear wheels up on them. It may seem odd to start work with the wheels on, but I hate wrestling with high-torque bolts with the car on stands or a jack. With the extra height you can get a decent bar on the bolts - and in the end my trusty 3/4” square drive with 1/2” adapter did the trick.

Can assure you even with the S3 310mm rear discs the carrier does not need to come off to replace discs. https://photos.app.goo.gl/wTXXmJPxWkn9yhUZ9

 

[JontyMort]

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Can assure you even with the S3 310mm rear discs the carrier does not need to come off to replace discs. https://photos.app.goo.gl/wTXXmJPxWkn9yhUZ9

I don’t think the word “even” is helpful there, since it implies that what works for the larger discs must work for the smaller ones. With the 272mm discs you definitely have to remove the carrier.

 

[george forbes]

You could be right but I would struggle to understand why. Same hub same size carrier but smaller disc. Lots of guys on the forum were lead to believe carrier had to be removed until a few leading garages and myself proved carrier did not need to be removed. Believe me I went through quite a few sleepless nights dreading removing that carrier.

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[JontyMort]

You could be right but I would struggle to understand why. Same hub same size carrier but smaller disc. Lots of guys on the forum were lead to believe carrier had to be removed until a few leading garages and myself proved carrier did not need to be removed. Believe me I went through quite a few sleepless nights dreading removing that carrier.

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I wonder if - counterintuitively - the larger the disc, the further away the edge of the disc (and the bracket, of course) are from the hub, and therefore the extra diameter actually gives the larger discs more wriggle room than the smaller ones? Others have commented that with some sizes they could (just!) get the worn discs off but not the new ones on.
As it is so marginal, you wonder why they didn’t make the very small adjustments necessary to ease the task. I’ve been working on Audi brakes for over 30 years, and the rears have always been a royal PITA. The fronts are a joy in comparison.
All the best.

 

[SDB]

I've replaced the rear discs on my 1.4 and no matter which way I moved, rotated, pushed and pulled, the carrier had to come off. Just couldn't get the angle to slide it past the carrier and clear of the hub.
As has been said - for a couple of millimetres adjustment in the design, it could have been so much easier.