Torsion beam and 310mm rear brake swap

[grabania]

Hi, I've got 2017 Leon 5F with electric handbrake and torsion beam. I've swapped rear brakes from 272mm to 310mm from Cupra Leon KL. During the swap I've encountered two things that made this modification a bit problematic:

1. Are motors of the electric handbrake reversible? Currently I had to install right caliper on the left side and vice versa because I wasn't able to fit the connector (no photo here, sorry)
2. Are there any brake disc covers for 310mm disc and torsion beam? I've received covers with the brakes, but they does not fit. I suppose they are from car with multi-link suspension and have different mounting points. Red circles are from 310 (new), blue circle is from 272 (old)
   
   

Thanks for any suggestions. Here is how the car looks with this 340/310 setup, much better compared to the stock 288/272

 

[East Yorkshire Retrofits]

I can’t comment on the fitment info sorry. But make sure you recode the brake control module to suit the larger discs!

 

[grabania]

I can’t comment on the fitment info sorry. But make sure you recode the brake control module to suit the larger discs!

Are you referring to the changes in byte 4 and 17 in the 03 Module? I've done this according to image found on some Golf 7 forum (Byte 4 from 24 to 54, Byte 17 from 48 to A8 - reverse of Byte 4).

But maybe there is some other coding for larger rear disc which I am not aware of? Thanks for response tho!

 

[East Yorkshire Retrofits]

MK100 ABS Coding (Shared) - Google Drive

docs.google.com

 

[SuperV8]

Interesting. There was never the 310mm rear brake fitted to a torsion beam car - so it will be upto you to modify your 310 splash shield to fit or leave it off.
Car you re-drill your new 310mm shield for the torsion mounting hole pattern?

The servo motors are handed left and right with unique part numbers - don't know the differences between the two?
Mechanically the motors won't care which side they are fitted - don't know if that would effect any brake system coding? I don't think the brake control module would know.

 

[grabania]

Car you re-drill your new 310mm shield for the torsion mounting hole pattern?

Probably yes, but 310 ones have different embossing with more groves. Also the center hole is a bit narrower but this should not be a problem. Currently that's my best bet to complete this mod. I am also thinking about cutting middle part with angle grinder and welding two covers into one, but that's the worst case scenario for me

Mechanically the motors won't care which side they are fitted - don't know if that would effect any brake system coding? I don't think the brake control module would know.

Currently I've installed left caliper on right side and vice versa so brake module does not care. I know that the left and right electric brake are distinguishable in ETKA, but maybe only because of reversed position of connector? That's my main concern, whether different PN is only because of connector position or because of other mechanical implications.

Thanks for suggestions though!

 

[SuperV8]

Probably yes, but 310 ones have different embossing with more groves. Also the center hole is a bit narrower but this should not be a problem. Currently that's my best bet to complete this mod. I am also thinking about cutting middle part with angle grinder and welding two covers into one, but that's the worst case scenario for me

Currently I've installed left caliper on right side and vice versa so brake module does not care. I know that the left and right electric brake are distinguishable in ETKA, but maybe only because of reversed position of connector? That's my main concern, whether different PN is only because of connector position or because of other mechanical implications.

Thanks for suggestions though!

Without checking! - I would guess the 'guts' of the servomotors are identical - with just differences in mounting.

 

[grabania]

Seat Leon Cupra 1M seems to had torsion beam with 256mm rear disc, but outer diameter of covers is 350mm. They are pretty cheap so I am inclined to test them

 

[East Yorkshire Retrofits]

Wouldn’t it be easier to upgrade to multilink suspension, you’d see more benefits too

 

[grabania]

Wouldn’t it be easier to upgrade to multilink suspension, you’d see more benefits too

I don't think my wallet would like that decision also I am more interested in electronics than in mechanics. That brake swap was more of a spontaneous decision rather than well though and planned mod.

While changing rear suspension to the multilink it would be obvious to consider 4x4 swap and with that change goes trunk floor, transmission, engine and so on... Too much for me

 

[Bluepower]

I don't think my wallet would like that decision also I am more interested in electronics than in mechanics. That brake swap was more of a spontaneous decision rather than well though and planned mod.

While changing rear suspension to the multilink it would be obvious to consider 4x4 swap and with that change goes trunk floor, transmission, engine and so on... Too much for me

4x4 swap is: gearbox, prop-shaft, rear axle with driveshafts and haldex and some wiring and coding. As far as I know there is no cutting/welding involved with the Leon mk3/5F

 

[grabania]

4x4 swap is: gearbox, prop-shaft, rear axle with driveshafts and haldex and some wiring and coding. As far as I know there is no cutting/welding involved with the Leon mk3/5F

There is a reason why folks cut trunk floor when doing 4x4 swap in Leon 5F HB check this one for example: https://www.drive2.com/l/670501708022940887/

Nevertheless, that's a bit off-topic from my problem and I would love to keep this topic rather focused on it.

 

[grabania]

Have some info about my 1st question - I've tried to replace right electric handbrake motor with left one on my old rear brakes (272) and unfortunately they are not reversible. Nut holes are off-center and it is impossible to screw right motor on left side and vice versa.

PN of old motors are 3Q0998281 and 3Q0998281A, and Leon KL ones are 5WA998281 and 5WA998281A. To me they look almost identical and I am really confused why I had to reverse rear brakes in order to connect them. I guess that without taking wheel of a car and comparing them side by side we can only guess.

 

[Mr Pig]

Just to check something. If you swapped the right and left callipers over does that mean that they are mounted upside-down?

 

[grabania]

Just to check something. If you swapped the right and left callipers over does that mean that they are mounted upside-down?

Not really, but the motor of electric handbrake is on the other side of the piston. Here you can see on the image how it looks in correct position and on the other (it the same calliper, just rotated). Left and right side are mechanically identical so it should not matter in which side they are installed

 

[Mr Pig]

I think there is another problem. The bleed nipple is in the wrong place. Instead of being at the top it's now at the bottom so it might be difficult or impossible to get a good bleed. And that's not a good thing!