gamblinfool

Just bumping this quickly. I've been able to locate a set of M5 brakes that are still on the car. I've got a '10 E61 xdrive manual.

I'm hoping someone can produce a laundry list of not only the major obvious items, but also any little hardware bits that might be needed. Here's what I've gleaned so far:

Needed from donor:
- calipers
- rotors (if in usable condition)
- rear hubs
- set screws (?)

Consumables:
- pads
- wear sensors
- rear wheel bearings

New (potentially optional) Items
- stainless lines
- 19" wheels (+20mm spacers? )

Am I missing anything?

Thanks all! - Jeff

E61FUN

I just completed an M5 brake update on a 2010 535iX.

If you have the complete brake equipment set coming off an M5 and assuming everything is in good repair (rotors aren't warped or heavily worn, calipers are not leaking, pads are good or you have replacement pads), you will only need brake lines and rear M5 hub/bearing assembly, as well as wheels with enough clearance and ~20mm less offset (although this depends on your wheel/tire setup and how flush you want your rear stance).

In addition, you will have to make a decision about the rear dust shield. IIRC forum members have gone different ways, either leaving off the dust shield or cutting them for clearance. I ran standard M5 shields and cut them for clearance, for now.

I have sourced a pair of M5 touring rear brake shields from over yonder, but until I see them in person I won't know if they mate up perfectly with the E60 Xdrive knuckle. The M5 touring *looks* the same, with the same airbag perch, though has a different part number, and likely has a larger bore on the inside to accommodate the larger diameter M5 half shaft CV (something Evan has some familiarity with now).

So whether our cars have the same outer face on the knuckle as the M5 touring allowing for larger M5 touring dust shield to mate up without modification is unknown to me.

Another choice is whether or not you wish to integrate the M5 electric vacuum booster and vacuum sensor system. Given that the hydraulic force and vacuum boost of the stock E60 system has not changed, and yet the brake system surface area has greatly increased, the result is a much firmer pedal. Brake pad type and rotor wear notwithstanding, without additional vacuum boost your brakes will not feel like the grabby oem brakes. But then they'll also work quite a lot better at 120MPH yet require more "leg".

gamblinfool

Interesting...do you have any before/after pictures of the rear dust shield modification by chance?

Also, a few ?'s about the M5 electric vacuum booster and vacuum sensor system:

- Are these generally expensive parts?
- What's the level difficulty of integrating them into the E61? I.e., any space issues? do they integrate w/ the electrical system...?

I'd prefer not to mess too extensively w/ the pedal feel if I can avoid it...

Thanks for the great info! - Jeff

E61FUN

The vacuum pump, mounting flange, main vacuum line trunk and sensor would be over $600 new, however most of the parts can be found used on eBay for less than $300 (far less if you take your time).

Space isn't a huge issue, given that we don't have a V10 wedged in the engine bay. The M5s use the same primary vacuum booster as our E61's, but it's clocked 180º, so the vacuum inlet is more towards the middle of the car.

As for electrical integration: I don't know. I'm working that problem right now. I have read that when the electric vacuum booster pump fails, an M5's pedal is hard, but brakes still work. So the early takeaway is that the booster runs all the time. Whether there is any dynamic vacuum regulation between the two vacuum sources I can't say. Then there's a sensor on one dead-end leg of the vacuum line that does something. Have to work out all these unknowns.

gamblinfool

Hmm...so I guess the take home message is buy all that stuff for now and sort it out later? ...

ericono

Reviving this thread again. Right now I am focused on the brakes themselves (calipers and rotors). Sounds like the M5 stuff can fit, but rear requires M5 rear hubs and spacers on the rear as well.

First question, did the 535 master cylinder work properly with the M5 calipers?

Second, could I use M5 front calipers and 535 rear calipers and minimize the parts and effort since most stopping power is provided by the front brakes anyway?

Forgot to add I already have 19" wheels and know I would need M5 rotors to go along with the M5 calipers.

Thanks,

Eric

hatterasman

Just completed the M5 brake swap on a 2008 E61. I can confirm that the master cylinder works fine and the vacuum boost is sufficient, with no noticeable change in required pedal pressure or feel using EBC Yellowstuff pads.

EDIT: After putting some miles on this, required pedal pressure is lower. The brakes are amazing! Stopping power is unbelievable. Pedal pressure is now very similar to the 08' 335i coupe.

bc419

I would be curious to know this as well.

hatterasman

I did the M5 brake upgrade and love it. The additional stopping power is awesome.

Everything works perfectly (master cylinder, ABS, etc.) All I changed on the braking system was the calipers and rotors.

The M5 rear flanges needed to make the rear calipers work change the offset by 20 mm. M5 flange is shorter so wheel moves to the inside. I measured 45 mm clearance from the inside of the wheel to the wheel well when deciding on my new rear wheel width and offset, so the wheel could still fit without a spacer, but will sit a little more than 3/4" to the inside.
Changing the flange is the same procedure as a rear wheel bearing replacement.

bc419

Thanks for the explanation for making the rear calipers work.

If I understand - it sounds like if you do the M5 front brakes, you should also do the rear conversion also?

If you don't do the rears, would there be too much front bias?