Brake Discs Size..

[AlRed86]

I want to order and then replace both rear discs & pads on my A3 8P 2.0tdi but when I'm searching for rear discs I'm given about 4 different diameter sizes and without being able to physically get the wheel off currently (knackered jack) and measure the disc I'm stuck. Does anyone know exactly? 

Is there not a standard size for my model? The Haynes manual has them as 286mm or 256mm for rears, so I'm fairly certain it's 256mm just by roughly measuring by eye but on these websites I'm getting a 255mm option too so don't want to order the wrong one. 

[Guest]

5 hours ago, AlRed86 said:

I want to order and then replace both rear discs & pads on my A3 8P 2.0tdi but when I'm searching for rear discs I'm given about 4 different diameter sizes and without being able to physically get the wheel off currently (knackered jack) and measure the disc I'm stuck. Does anyone know exactly? 

Is there not a standard size for my model? The Haynes manual has them as 286mm or 256mm for rears, so I'm fairly certain it's 256mm just by roughly measuring by eye but on these websites I'm getting a 255mm option too so don't want to order the wrong one. 

What rear brakes are fitted depends on the car's build codes.

If you're looking for various parts on the car, such as brakes and suspension, it's probably best to get a full list of all the car's build codes. There's a seller on eBay that charges about 3 Euros (about £2.50) for all of the car's build codes. Search "audi vin decoder factory options" to find the listing on eBay.

listing on eBay for "audi vin decoder factory options"

https://www.ebay.co.uk/itm/224631127243

There are many versions of the 2.0TDI engine, front wheel drive, four wheel drive, 140HP, 170HP, etc. There isn't just one rear brake size that covers all of these versions.

If you've got a front wheel drive 2.0TDI, I expect you have 253x10mm rear brakes with either build code 1KD or 1KQ.

The 253x10mm rear brake discs are sometimes shown as 255x10mm on various parts websites, but the build code 1KD or 1KQ would show that these are interchangeable with 253x10mm.

Beware of build code 1KE which uses a bigger 256x12mm rear brake discs. This is different to the 253x10mm rear brake discs.

Audi parts catalogue (search "audi LLLparts" to find this website)

https://www.lllparts.co.uk/catalogs/audi/RDW/A3/412/6

Once you have all of your car's build codes, you can enter them into the "vw codes decoder" to find out what they all mean.

vw codes decoder

http://igorweb.org/equidec.aspx

Edited July 13, 2023 by Honda

[AlRed86]

Thanks for the response, I've bought the car build codes off that eBay guy and turns out the rear discs code is 1KD, so they're the 253x10mm ones. 

[AlRed86]

An update:

I replaced the discs and pads, they sounded fine when I took the car around the block all good. Today I've drove out and after a while of more braking, I've noticed the grinding came back, back left from the sounds of it and lucky I was just about back home but it sounded harsher this time.

The back left was also the caliper which was an absolute bugger to wind back in. Potentially seized caliper then? 

Edited July 18, 2023 by AlRed86

[Steve Q]

Yep could be seized. You've done good.with diagnostic process so far. 

[cliffcoggin]

On 7/18/2023 at 12:23 PM, AlRed86 said:

 

The back left was also the caliper which was an absolute bugger to wind back in. Potentially seized caliper then? 

Undoubtedly.

Edited July 21, 2023 by cliffcoggin
Spelling error