Yes, another brakes "drum to disc conversion"

[makymak]

Good evening! 

 

I know the subject has been exhaustively discussed. But I still can't find one tiny detail. 

 

My Octy comes with rear drums. I have a whole beam with everything on it (calipers, disks, stub axles, abs sensors, handbrake cables even the shock absorbers - Bilstein sprint - with their top mounts). The most obvious thing is to replace the whole beam at once. But this means I have to visit the garage to have the car raised. I wonder if my drum beam has the same side mounts so I can leave the original beam on the car and mount on it the disk stub axles, calipers and dust covers. If this is the case, I can do it on my parking lot with stands. Does that sound doable?

[makymak]

Well, no answers but I try little more. 

 

The rear beam I bought comes with 256mm disks. My car is a 1.6l petrol (AVU) and I see on the net that it comes also with 256mm front disks. I haven't measured mine but if considering this to be true, would it be an overkill to have the same disk diameter both front and rear? Furthermore, would it be an unbalance factor under hard braking? 

 

A thought of upgrading, what are the biggest front disks that fit in the oem 15" alloy rims? 

 

I haven't assembled the rear disks, yet. Should I search for the 232mm rear disk setup, for peace of mind? 

[KenONeill]

12 minutes ago, makymak said:

A thought of upgrading, what are the biggest front disks that fit in the oem 15" alloy rims?

280mm, which are also the biggest discs that will fit in the FSIII calipers.

[makymak]

Thanks @KenONeill

 

What parts will I need to replace to fit the 280mm front disks?

 

If I choose to keep the oem (256mm?) should this leads to brake unbalance and loose of control? The car has ABS but I don't trust it a lot! 

Edited 26 January, 2023 by makymak

[makymak]

OK, after a little searching I found I have to replace the bearing carriers and discs. The problem is that I don't have the part numbers for the 280mm carriers. The parts sites are quite confusing since they don't declare what carrier matches what disc. If anyone knows the part number for the 280mm carriers or on what engines they where used and willing to help, I would appreciate it! 

 

Of course, I will keep on searching myself, too. 

[KenONeill]

24 minutes ago, makymak said:

If anyone knows the part number for the 280mm carriers or on what engines they where used

Definitely on the TDi (110).

[makymak]

38 minutes ago, KenONeill said:

Definitely on the TDi (110).

That's very helpful! 

Thank you! 

[makymak]

Update:

 

1.4l 16v, 1.6l 8v and maybe 2.0l 8v petrol engines: 

- Front: 256mm discs/FSIII calipers

Steering knuckles/bearing-caliper carriers part numbers: 1J0407255N/1J0407256N

- Rear: drums or 232mm discs. 

 

TDi and maybe SDi diesel engines:

- Front: 280mm discs/FSIII calipers 

Steering knuckles/bearing-caliper carriers part numbers: 1J0407255AG/1J0407256AG

- Rear: 232mm discs

 

1.8l 20v petrol (inc vRS) 

- Frond: 288mm discs/non FSIII calipers with detachable carriers

- Rear: 256mm discs (vented for vRS) 

 

To go from 256mm to 280mm we need to replace only the discs and the knuckles (bearing carriers) as the calipers are directly bolt on them. Same calipers (FSIII) and pads for both diameters. 

 

To go from 256mm/280mm to 288mm we need to replace the whole hub. 

 

Smaller rim for 256mm front: 14"

Smaller rim for 280mm front: 15"

Smaller rim for 288mm front: 16"

 

Smaller rim for both 232mm/256mm rear: 14"

 

 

These is what my tiny research gave me back. Hope it's accurate enough (feel free to make any corrections). 

 

[Carlston]

1 hour ago, makymak said:

Update:

 

1.4l 16v, 1.6l 8v and maybe 2.0l 8v petrol engines: 

- Front: 256mm discs/FSIII calipers

Steering knuckles/bearing-caliper carriers part numbers: 1J0407255N/1J0407256N

- Rear: drums or 232mm discs. 

 

TDi and maybe SDi diesel engines:

- Front: 280mm discs/FSIII calipers 

Steering knuckles/bearing-caliper carriers part numbers: 1J0407255AG/1J0407256AG

- Rear: 232mm discs

 

1.8l 20v petrol (inc vRS) 

- Frond: 288mm discs/non FSIII calipers with detachable carriers

- Rear: 256mm discs (vented for vRS) 

 

To go from 256mm to 280mm we need to replace only the discs and the knuckles (bearing carriers) as the calipers are directly bolt on them. Same calipers (FSIII) and pads for both diameters. 

 

To go from 256mm/280mm to 288mm we need to replace the whole hub. 

 

Smaller rim for 256mm front: 14"

Smaller rim for 280mm front: 15"

Smaller rim for 288mm front: 16"

 

Smaller rim for both 232mm/256mm rear: 14"

 

 

These is what my tiny research gave me back. Hope it's accurate enough (feel free to make any corrections). 

 

 

Octavia MK1

256x22mm front brake discs

60HP 1.4 petrol

68HP 1.9 diesel

75HP 1.4 petrol

75HP 1.6 petrol

101HP 1.6 petrol

102HP 1.6 petrol

280x22mm front brake discs

90HP 1.9 diesel

100HP 1.9 diesel

110HP 1.9 diesel

116HP 2.0 petrol

125HP 1.8 petrol

288x25mm front brake discs

130HP 1.9 diesel

150HP 1.8 petrol

312x25mm front brake discs

180HP 1.8 petrol

 

15" rims fit over 288mm front discs.

 

Jurid on autodoc seems quite accurate for front brake disc size.

 

Edited 28 January, 2023 by Carlston

[makymak]

@CarlstonThanks for the correction!!!

I think it's useful for future reference! 

[Carlston]

Octavia MK1

256x22mm front brake discs and 230x32mm rear drum brakes

60HP 1.4 petrol

68HP 1.9 diesel

75HP 1.4 petrol

75HP 1.6 petrol

101HP 1.6 petrol

102HP 1.6 petrol

280x22mm front brake discs and 232x9mm rear brake discs (4WD has 239x9mm rear disc brakes)

90HP 1.9 diesel

100HP 1.9 diesel

110HP 1.9 diesel

116HP 2.0 petrol

125HP 1.8 petrol

288x25mm front brake discs and 232x9mm rear brake discs (4WD has 239x9mm rear disc brakes)

130HP 1.9 diesel

150HP 1.8 petrol

312x25mm front brake discs and 256x22mm rear brake discs

180HP 1.8 petrol

 

As you can see in the above chart, both 280x22mm front brake discs and 288x25mm front brake discs are matched to 232x9mm rear brake discs, except that the Octavia MK1 4WD cars always have the larger 239x9mm rear disc brakes. This makes sense, because the four wheel drive system increases the weight over the rear wheels.

 

However, it always makes sense to check the car's build codes in case any particular car doesn't follow the above.

 

Edited 29 January, 2023 by Carlston

[makymak]

A 150HP 1.8 has rear a 256 x 9mm as mine (the whole beam) comes from this car. 

[makymak]

16 hours ago, makymak said:

A 150HP 1.8 has rear a 256 x 9mm as mine (the whole beam) comes from this car. 

Sorry, wrong information. Too many searching for my poor old tired brain. Rears 232mm x 9 mm exactly as @Carlstonsaid.

 

By the way, @Carlston's info above are the most complete brake dimensions annex. 

[makymak]

The upgrade completed! 

Massive improvement over the previous setup. I guess the difference is mostly from the front upgrade. But I too like the view of the rear discs. The front 280mm look huge into the oem 15" alloys. Thank you all for the help!