Brakes and calipers

[TernandoFoledo]

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 - 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

[Mike W.]

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.

[TernandoFoledo]

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]

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]

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 - 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/

[TernandoFoledo]

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

[TernandoFoledo]

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]

OK, TIME FOR SOME UPDATES

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

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!

[TernandoFoledo]

Hey guys,

got some trouble in the way and hoped someone could shed some light here.

We managed to adapt the center hub from the E12 to recieve the 'modern way' of rotors, but we are having trouble with the spacing of the carriers fixing point.

I've seen people talking about doing this change into E12 based E24s, can anyone help here? It seems that the caliper cant be fixed in the space to match this size of rotor. I might need some bigger rotors (330mm), but then I hit the 30mm thick mark, which I don't think E34s calipers can match.

Hope to hear from anyone

[TernandoFoledo]

Well, here we go!

We managed to find a solution.

The rotors from the 328 F30 are 330x24, with a tiny difference in the hats height (4mm), which made possible the conversion.

Now we are finishing the brakebooster part, which is a pain, due to the fact that involves the whole e34 structure and the repiping of the car.

Lets see how it goes