Leon FR 5F1 282mm to 312mm conversion

LeonFR_TDI

Active Member
Dec 1, 2022
10
6
Hi, i have a 2015 Seat Leon FR TDI with the 288mm front brakes. I want to upgrade those to the 312mm brakes that the 1.8TSI FR has standard. Somewhere on this forum I've read that the only differences between those are the brake discs and the carriers. My question, to someone who has already done this, is if those are really the only differences and if so, what is the part number for the 312mm carrier which would fit my Leon.
Thanks
 

Lozzy15

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Staff member
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Mar 24, 2015
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Ilkeston, Derbyshire
There a fair bit of information in this thread here:
 

LeonFR_TDI

Active Member
Dec 1, 2022
10
6
There a fair bit of information in this thread here:
Yes, i have read this thread and many others but there isn't a conclusive answer, the thread you linked says that the calipers are also different, another thread says they're the same as the 288mm ones, that's why i wanted advice from someone who has done this.
 
Hi, i have a 2015 Seat Leon FR TDI with the 288mm front brakes. I want to upgrade those to the 312mm brakes that the 1.8TSI FR has standard. Somewhere on this forum I've read that the only differences between those are the brake discs and the carriers. My question, to someone who has already done this, is if those are really the only differences and if so, what is the part number for the 312mm carrier which would fit my Leon.
Thanks
Make sure you code your ABS accordingly when you change the disc size

As for the part numbers, send me your VIN and I'll take a look at it
 

LeonFR_TDI

Active Member
Dec 1, 2022
10
6
Thanks for the reply, i found the part numbers for the 312 carriers, if anyone wonders they are 8V0 615 125A and 8V0 615 126A.
As for the ABS coding, this is the first I'm hearing about this. Is is something i can do alone or does a delalership have to do it?
 
Thanks for the reply, i found the part numbers for the 312 carriers, if anyone wonders they are 8V0 615 125A and 8V0 615 126A.
As for the ABS coding, this is the first I'm hearing about this. Is is something i can do alone or does a delalership have to do it?
A dealer "cant" do it. It's easy enough to do with VCDS etc if you take your time. It's important you do this for correct operation of ABS/TCS/ESC

Byte 4 should be either hex 30, 31 or 34 depending on the PR code of the brakes you've installed. Remember it starts at byte 0, so it's actually the 5th byte.

Looking at the parts diagram it looks like the only 312mm front brake configuration on the Leon is 1ZA

30 being 1ZA (312X25MM)

This is also mirrored in Byte 17. (Mirror byte 4 binary in byte 17 binary).

Example of how mirroring works
lets say that Byte 0 is 0E
Take the Binary value of 0E (Binary 00001110 in LCODE)
and read it backwards to get the mirror of the byte
Which would make Byte 15 be 70 (Binary 01110000 in LCODE)

You have to change both bytes together otherwise you won't be able to save the changes.
 
Last edited:

LeonFR_TDI

Active Member
Dec 1, 2022
10
6
*Update*

Happy to say that it really is just a matter of replacing the caliper carriers, the calipers stay the same!
 

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Oct 26, 2019
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I do, the brake response is much better than it was and the brakes feel more grabby. Some of that could be due to the Brembo brakes and pads i went for though.
How it went with the coding? I want to do the same. Wanted to trade my 1.5TSi for Cupra. But after Chip and CAI it is already a lot of fun. Just the brakes need upgrade now.
 

DEAN0

Old Git
Feb 1, 2006
5,297
307
Preston - UK
How it went with the coding? I want to do the same. Wanted to trade my 1.5TSi for Cupra. But after Chip and CAI it is already a lot of fun. Just the brakes need upgrade now.
I am not sure the 1.5TSI can be upgraded in the same way.
I believe the 1.5TSI has the smaller FS III brakes fitted.
The FS III brakes have the carrier built in to the steering hub - it is not removable to bold on another carrier.

To upgrade FS III brakes - you would first need to swap the steering hub for the FN series hub.
 

SuperV8

Active Member
May 30, 2019
1,348
594
I am not sure the 1.5TSI can be upgraded in the same way.
I believe the 1.5TSI has the smaller FS III brakes fitted.
The FS III brakes have the carrier built in to the steering hub - it is not removable to bold on another carrier.

To upgrade FS III brakes - you would first need to swap the steering hub for the FN series hub.
Checked a 130 & 150 1.5tsi and the both had the 288x25mm TRW front brake - not the smaller 276x24mm FSIII brake.
 
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