Difference between early and late front calipers?

[rolfi]

Hello.


I have just bought a near mint 1976 525.

It has been sitting in a garage for years, so the brakes are somewhat stuck. They work, so it is driveable, but they're supposed to work a whole lot better than they currently do.

As I have to buy new/reman calipers I might as well buy some 535i/M535i ones. I see the part numbers for all preface calipers go up to 09/76 and the facelift calipers go from 09/76 and up.

What is the difference between preface calipers and the 535i ones?
Will the 535i ones fit on a preface-model, or will I have to swap the whole suspension for a 535i one to make them fit?

Swapping the whole suspension is out of the question, as this is no racecar. Then I'd rather go with original calipers

[DEMIURGE]

There are three types of brake discs for e12. Only the first two were used for 525 e12, the third is used for 535. Dimensions are in "mm".
1. 12.7x280 - solid brake discs
2. 22x280 - ventilated brake discs
3. 25x280 - wider ventilated brake discs.

So, the calipers for these brake discs are different. Actually, the shells are identical, but the 2-nd and the third type have spacers (535 has wider spacers than 525 ventilated). Beside these spacers they also have difference in the "brake pad mounting kit" - again in the width.

If you want 535 calipers - you have to take and the brake discs also and the worse part - the wheel hubs...... (because of the different offset).
So, maybe, it is a good idea to renovate your old calipers.

[DEMIURGE]

I'm sorry for my off-topic question - can you tell me the price of these 535 calipers (of course, if it isn't a secret) - as I'm living in Europe and this is interesting to me. These calipers are expensive enough, more than 300 EUR and you have to send the old caliper sets also (or 150 EUR deposit).
You can buy a whole e12 at this price...

[rolfi]

Thank you very much for the detailed answer

I haven't directly found any 535i ones, but I though if it were a direct fit I might do some research to get a pair.

But I think I'll stick with the ventilated ones then. They are €180 per side (plus around €40 in deposit), so it's a ok price.

Again, thank you for your very detailed answer

[DEMIURGE]

I'm sure (almost ), you will not notice the difference between 535 and 525 ventilated brakes. As you say - your 525 isn't a race car.
The only real difference will be in a slightly slower rise of the temperature of the brake parts of the wider (more metal) and a little bit better ventilated discs of 535, while using often and aggressive the brakes.
But even the solid brake discs versions of e12 (more than 30 years old, but 4 pots, 2 separated brake lines) are better than some present day middle cheap brakes. Of course, the ventilated are even better and they are absolutely enough to brake the weight of e12.
ALWAYS use good brake pads !!!

[cpalmer]

Since your going to do the calipers, and the car sat for a long time, you might want to think about doing the Master Cylinder as well. There's probably some junk it. I just did this all yesterday and am happy the brakes are ALL DOne.

ALso, welcome. Hope things are good in Norway.