Brakes and calipers

Post your E12 technical questions and comments here. Please, no off-topic posts.

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TernandoFoledo
Posts: 14
Joined: Sun Jul 16, 2017 3:34 pm

Brakes and calipers

Post by TernandoFoledo » Tue Mar 05, 2019 10:07 pm

Hey people, how are you?

So i've been looking around here, and many other places, but couldnt find many info about the brakes, as I needed. The other topic I've opened helped a lot - thanks to everyone that took part there :D - but i still have some crucial doubts

With that in mind, I would like to open this topic so we can discuss them a little bit :)

My main doubts are:

- my car is a 74 520, with front disks and rear drums. With the original calipers and a 15" wheel, whats the max rotor size I can fit? 286mm?

- my calipers need some spacers to go 25mm vented disks, or they fit them "stock"? Or do i need another part for this? Another calipers from newer models?

- the rear, to adapt some calipers, will need any special care? I noticed that the rear trailing arm is different from drums and disks models, which got me a little confused. I thought that it would be just swipe a bracket there, the plate and calipers.
Since the e28 swap is a little out of option, I'm thinking the e34 calipers, since my wheels are from the 540.

Im after a better stopping power and considered wilwood and other stuff, but with a 4pot original caliper, I thought to improve it and try the best on that platform. Would anyone recommend anything different?

Im all ears :)

Thank you very much!

Best,
Fernando

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Mike W.
Posts: 2447
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Re: Brakes and calipers

Post by Mike W. » Fri Mar 08, 2019 10:16 pm

You can't go to a significantly larger rotor with the stock calipers. Nothing else besides E12 (well, E3 also, but E12s have bigger brakes) fits E12s. Drill on down in Realoem to see what came on what. Likely your best and easiest upgrade will be to find brakes off a later E12 that are 280X22 front rotors. E28 brakes do not fit. E23 brakes are more similar to E12, but not much larger and they don't fit either. Technically M535i brakes from the ultra rare E12 M535i are 25MM thick and better, but no larger in diameter than many later E12s such as 528s. A bit better fade resistance, but that's all.

Nothing else fits E12s without a lot of machine shop work.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter

TernandoFoledo
Posts: 14
Joined: Sun Jul 16, 2017 3:34 pm

Re: Brakes and calipers

Post by TernandoFoledo » Sat Mar 09, 2019 3:49 pm

Arent we blessed then? Hahhahaha

Well, that settles it. The 4pot caliper is the only thing that calms my nerves. I will stick to the original 520 rotor (or there is another one thats better and doesnt need a adaptation?) And work in the pads and fluid.

Thanks a lot Mike!

TernandoFoledo
Posts: 14
Joined: Sun Jul 16, 2017 3:34 pm

Re: Brakes and calipers

Post by TernandoFoledo » Wed Nov 13, 2019 11:36 am

Soooo.... I still havent tackled this matter, and am still studying what to do - and came with this:

I've read a lot ofposts and articles here, bigcoupe, bimmerworld and etc, about the upgrades to the E12 brakes. My system is the well known dual circuit in the front, and 4 pot calipers, but with Drum Brakes in the back.

I don't need something that will bolt right up, because i'm working with a shop that can manage to help develop brackets and stuff, so my ideas went like this:

I was after some 4 pot brembos to the front, to manage a bigger disk, but with all the reading, it seems to me that the original caliper have more than enough clamping force - but I dont know if, and how, I could put 330x24mm disks in the front, adapting the existing mounting point with an 'extensor'. Also, with the 24mm width, I would need an spacer? Like 2mm spacers?

A lot of other options were described in my research, but I think that they would involve bigger modifications, or am I crazy? I'm totally open here to discuss other options, like E34 540i ones, but I was afraid to increase too much the clamping.


To the back I was searching and wanted to make an E28 rear swap, but in Brazil we just don't have this kind of spares (we got, mainly E34 and 'newer' models). This would allow a lot of easy swaps, but I will have to stick to the original trailing arms, that has Drum Brakes.


I found some Mini Cooper rear calipers, which have the hand brake integrated, and would help a lot since I would have to adapt the inner part of the handbrake. They have 36mm pistons, and I was thinking of some 300x20mm disks, which were some that I could find easily in my market. Any ideas in this matter? Would it work? And how could I make this in the safest way?

The calipers are a 'regular' model, from TRW.

My wheels are MK Motorspot 17x8.5, which I bought just to accomodade some better brakes.

I understand that there are a lot of other factors in play, but I'm making a Restomod project and would like to make this upgrade.

Thank you very much for your attention, and if there are any doubts in the project to help develop the discussion, please, ask me. I was trying to make it short so wont be a pain in your ass :)

PatinaBeforePolish
Posts: 239
Joined: Sun Jan 18, 2015 1:22 pm
Location: Baltimore, Md.

Re: Brakes and calipers

Post by PatinaBeforePolish » Thu Nov 14, 2019 7:22 am

TernandoFoledo wrote:
Tue Mar 05, 2019 10:07 pm
Hey people, how are you?

So i've been looking around here, and many other places, but couldnt find many info about the brakes, as I needed. The other topic I've opened helped a lot - thanks to everyone that took part there :D - but i still have some crucial doubts

With that in mind, I would like to open this topic so we can discuss them a little bit :)

My main doubts are:

- my car is a 74 520, with front disks and rear drums. With the original calipers and a 15" wheel, whats the max rotor size I can fit? 286mm?

- my calipers need some spacers to go 25mm vented disks, or they fit them "stock"? Or do i need another part for this? Another calipers from newer models?

- the rear, to adapt some calipers, will need any special care? I noticed that the rear trailing arm is different from drums and disks models, which got me a little confused. I thought that it would be just swipe a bracket there, the plate and calipers.
Since the e28 swap is a little out of option, I'm thinking the e34 calipers, since my wheels are from the 540.

Im after a better stopping power and considered wilwood and other stuff, but with a 4pot original caliper, I thought to improve it and try the best on that platform. Would anyone recommend anything different?

Im all ears :)

Thank you very much!

Best,
Fernando
Here’s a good example of a blend of e34 and e28 brakes and suspension upgrades on an E12. Can’t determine how much fabrication was involved but parts used are displayed in one of the pics.

https://bringatrailer.com/listing/1980-bmw-528i-5/
78 F150
79 528i
81 528i parts car
01 540i
86 944
08 X3 don’t judge me it’s there to preserve the others

TernandoFoledo
Posts: 14
Joined: Sun Jul 16, 2017 3:34 pm

Re: Brakes and calipers

Post by TernandoFoledo » Thu Nov 14, 2019 7:40 am

This is a very nice build indeed, but involved an E28 rear end swap - something I was after, IF I could find an E28 around here.

Unfortuntelly Brazil didnt get those cars officially, so they are very rare here, reason why I'm studying these modifications :)

I will keep studying this example you sent to see if some light may come up to me :D

TernandoFoledo
Posts: 14
Joined: Sun Jul 16, 2017 3:34 pm

Re: Brakes and calipers

Post by TernandoFoledo » Tue Nov 26, 2019 10:19 am

So, new options arrived in my head and would like some guidance from the experts :)

I was considering keeping the original calipers and use 302x22mm vented rotors from e34 530i in the front and a generic rear caliper (Akebono one, with 35mm piston and hand brake integrated as I need it) with 300x10mm rotors also from 530.

Would the vented work in the 520 e12 caliper I have in the front? My disks should be 12.7.mm thick, but I read it can go up to 22mm, since the 528 used it, right?

What would you think about that?

TernandoFoledo
Posts: 14
Joined: Sun Jul 16, 2017 3:34 pm

Re: Brakes and calipers

Post by TernandoFoledo » Mon Dec 09, 2019 10:42 am

OK, TIME FOR SOME UPDATES

So we got our minds decided in the following setup below, but we need desperate help with the rotors :x

ROTORS
E34 302x28 in the front and 300x10 in the rear, but here we dont dont know how to manage the wheel hub thing, since E12s have the rotor behind the Hub and e34s uses the modern way in the front. What could we do here? Anyone has any idea?

BRAKE BOOSTER
BMW E34 remote Brake Booster, due to the lack of space in the engine bay and the M52tu intake;

CALIPERS
Front: 540i E34 single piston
Rear: Ford Fusion single piston, with hand brake integrated - was the closest I could get to E34s rears

I will try to keep it updated the best that I can!

Thanks!

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