E86 non-M, rear brake upgrade. Parts list - final check

Meds

Meds

Active member
 Beds/Cambs
After much faffing, deliberation and procastinating, I'm finally ready to continue the brake upgrade on the Coupe.
The fronts were done ages ago (E8x 135i stock / 130i factory upgrade 'BMW Performance' option)

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It's now time to complete the project. I don't do anything fast, so it'll be a winter project, no doubt taking me well into the summer of 2026!.

Researching what options are available took a while, there's many conflicting reports of what works, what parts are required. Upgrades seem to be done mostly on the M, not the 3.0si and sometimes differentiating between them was tricky. I also used GPT to confirm my own findings but even that needed correcting due to it suggesting the wrong parts.

Anyway, here's the parts list:

Calipers:
Porsche 996/Boxter S rear calipers: 996.352.421 and 996.352.422
Rotors:
BMW E46 M3 rears (328×20 mm): 34212229379
Carrier backets:
Creations Motorsport kit: BR0038
Lines:
Creations Motorsport HEL lines: BL13
Because I'm forever removing/install the wheels on this thing:
Stud conversion: 75mm M12 X 1.5 x20
Handbrake parts:
Backing Plates (Dust Shields / Shoe Carriers)
BMW left PN: 34-21-2-282-965
BMW right PN: 34-21-2-282-966
Handbrake Shoes (185 mm spec)
BMW PN: 34 41 6 761 293 x2
Adjusters / Spreaders
BMW PN: 34 41 1 163 461 x2
BMW PN: 34 41 1 163 462 x2




Can anyone on here shout anything I've missed, glaring problems, other options, concerns or questions.. ?

Thanks.
 
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@Meds excited to follow this latest work.
Apart from pads and sensors that go without saying, will you need any handbrake parts either renewed or replacements if different?
Will you be painting yellow to match the front calipers and sourcing some performance decals?
 
RMB said:
@Meds excited to follow this latest work.
Apart from pads and sensors that go without saying, will you need any handbrake parts either renewed or replacements if different?
Will you be painting yellow to match the front calipers and sourcing some performance decals?
Click to expand...

Yes BMW Pheonix Yellow to match the fronts (that's the OEM colour for the calipers if ordered for the 130i). I think this time I'll do the painting myself.
I dont think I'll add matching decals (I already have the rear specifc BMW decal in my spares box) as they're not BMW OEM units.
I'll get a new Porsche decal, keeping them true to their roots. :unsure:
Or leave blank, or a 'Brembo' maybe.?

Regarding the wear sensor.. I thnk this is just a zip tie out the way job. I dont think the BMW sensor fits the Porsche pads.
 
Cool, I would leave the new calipers blank then if you’re not putting the bmw performance ones on, just imho. 👍🏻
 
TriggerFish said:
Such a great colour!

Don't forget the handbrake shoes and disk backing plates.
Click to expand...

Good call.

[Edit] Yes, my current non-M handbrake shoes will not fit the M disc, same goes for the backing/protection plates.
I need to research and spec these.
 
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RMB said:
Cool, I would leave the new calipers blank then if you’re not putting the bmw performance ones on, just imho. 👍🏻
Click to expand...

I dont think any 'BMW Performance' rears from the E8x generation fit without loads machining/faffing to disc hats/ mounting hardware..
It's Porsche 996/Boxter/Cayman, A specific Aston Martin caliper or the job gets much more involved.
(from what I've read, though, not experienced)
 
Sorry I was referring just to the decals on the Porsche calipers.
 
RMB said:
Sorry I was referring just to the decals on the Porsche calipers.
Click to expand...
Ahh, I get you now.. Yeah adding BMW decals to the Porsche calipers feels a little wrong.
Either Porsche, Brembo or blank.

I kind of like the idea keeping 'Porsche'. It'll be a good talking point, if anything.
 
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Meds said:
Good call.
Are the handbrake shoes a wear item, while in there, type job? Do I need a different part number to what I have now on the non-M?
The backing plate, is a different part requirement due to fitting issues or can I just modify the existing with a few bends?.?
Click to expand...
You can cross reference the other parts here, but I'd expect the actuator/pins to be the same on the M3 handbrake https://www.realoem.com/bmw/enUS/showparts?id=DU52-EUR-09-2006-E86-BMW-Z4_30si&diagId=34_1293

For the handbrake shoes - the E86 ones aren't the same as the E46 M3 ones so you'd need E46 M3 handbrake shoes and back plates, at a guess - which is a pain, as to fit them properly is a wheel bearing removal job, although I have seen people cut a relief in the shoe to get them over the bearing face. I was going to upgrade my E86 to E46 330i/d rears, but couldn't be bothered, due to the back plates.

The E46 330i/d actually has larger rear discs than the E85/6 Si models, too (320mm vs our 294mm if memory serves me) - so that could be an easier/cheaper upgrade path. Although not as visually catching as some 4 pots, however!

With the back plate, you could probably just cut the inward facing lip/fold off, and it would be fine for the discs, but I wouldn't want to stake any money on that claim, as the handbrake shoes might sit further out/in different holes, in which case, the backplate would need replacing.
 
TriggerFish said:
You can cross reference the other parts here, but I'd expect the actuator/pins to be the same on the M3 handbrake https://www.realoem.com/bmw/enUS/showparts?id=DU52-EUR-09-2006-E86-BMW-Z4_30si&diagId=34_1293

For the handbrake shoes - the E86 ones aren't the same as the E46 M3 ones so you'd need E46 M3 handbrake shoes and back plates, at a guess - which is a pain, as to fit them properly is a wheel bearing removal job, although I have seen people cut a relief in the shoe to get them over the bearing face. I was going to upgrade my E86 to E46 330i/d rears, but couldn't be bothered, due to the back plates.

The E46 330i/d actually has larger rear discs than the E85/6 Si models, too (320mm vs our 294mm if memory serves me) - so that could be an easier/cheaper upgrade path. Although not as visually catching as some 4 pots, however!

With the back plate, you could probably just cut the inward facing lip/fold off, and it would be fine for the discs, but I wouldn't want to stake any money on that claim, as the handbrake shoes might sit further out/in different holes, in which case, the backplate would need replacing.
Click to expand...
This is exactly why I came here! Great stuff, very valuable. Thanks.

I've found the below from some frantic Googling:

Backing Plates (Dust Shields / Shoe Carriers)
BMW left PN: 34-21-2-282-965
BMW right PN: 34-21-2-282-966
Handbrake Shoes (185 mm spec)
BMW PN: 34 41 6 761 293 x2
Adjusters / Spreaders
BMW PN: 34 41 1 163 461 x2
BMW PN: 34 41 1 163 462 x2

Pretty sure I can get a kit which includes shoes and adjusters but I need to check that..
 
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I've read about using the 330i rear setup.. Caliper, disc, carriers and pads are a bolt on 'upgrade' but dont give the visual bang as a nice 4 pot set will (and to match the fronts better)

I agree pulling the hub assembly to fit the backing plate seems like an absolute PITA for the Porsche/M3 setup.. At least with the 330i setup, the 3.0si backing plate can be bent to fit, there's no other reason to swap it other than it's shape which we know can be pursuded with some gentle force.
It'll help to equal out the brake bias, though. 294mm to 320mm.

Hmmm, maybe this is the way forward.?
 
No worries!

The 330i/d 320mm setup uses different handbrake shoes to the E85/6, so you might run into the same problem there with the backing plates as you would with the M3 setup.

I'm sure some E46 guys will have done the upgrade, so I bet you could check on those forums and see what's needed for smaller 294mm -> 320mm rear set up.

The E85/6 back disk was used on the E46 up to the 328i, but not the 330i/d - so it maybe that it's the same amount of backplate work to go to either M3 or 330i/d discs/handbrake.
 
www.e46fanatics.com

The Comprehensive E46 Brake Upgrade Guide

First off let me say that this thread is not meant to bash anyone or anything, it is meant purely as a reference. Seeing as I do not own every single E46 ever made I cannot 100% guarantee a single solution will work for you, the best I can do is cross reference part numbers. Please avoid filling...
www.e46fanatics.com www.e46fanatics.com

Looks to outline the 294 -> 320mm quite nicely - does mention needing to swap the hub (seems extreme - maybe it's debunked further down the thread?!) for the parking shoes..
 
Looks like there was an E46 330i rear perforated disc but it’s NLA. I’m sure you can get non bmw though.
 

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Upon some checking, the E46 330i rear disc uses the same handbrake shoe size as the E46 M, so if I go that route to avoid the backing plate drama, I'll still need to deal with the parking shoe faffery.

Swings and roundabouts.
 
Will you have the ability to adjust the brake bais? I'd be concerned about being over braked on the rear given that the callipers for the Boxter are presumably specified for a rear engine car with a lot of extra weight in the back end.
 
Adjusting the bias is not possible, other than hardware swaps.
Don't forget my fronts have already had a large upgrade so anything I can do to compensate that the better.
The difference (between front back) of disc size after I upgrade the rears roughly falls in line with the standard difference so it should be fairly similar. (Yes, I know disc size alone is not conclusive to calculate brake force, but it's a start)

The Porsche caliper setup is a common rear upgrade on the Z4 and M3 to compliment any front upgrade, with nobody stating they're overly concerned about a noticeable negative bias change using the Porsche rears.

Most just leave them standard, though. But my OCD is taking control and I feel I need to match both ends..
 
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