E89 Z4 4-corner big brake upgrade with Brembo m-sport calipers

[billj457]

Great thread! If you happen to still have your stock 325M wheels, do they fit in front with the 370mm setup?

Just to follow up, I had some brake maintenance to do on my e90 335 and while the calipers/rotors were off, I mocked up the S2NHA caliper and tried to install one of my e89's 325M wheels. Bad news is they don't fit, they might fit if you remove the little pad weights, though. Good news is that my 335's 18" Apex EC7's fit.. Time to start saving for another set of EC7's!

 

[Mittu]

Still not happy with it. Mid-soft pedal feel on first push, hard on second. I did a power bleed twice. I've done one manual bleed. ISTA vibrate on all. I'm going to do another manual bleed (person pressing pedal).

I've heard from a number of people running bigger brakes setups that the stock booster works fine. So I don't think it is a booster size issue (and Z4 booster is unique ... at least I've not found a swap). I think this is a pesky Ex bleed issue.

When I did my X5 big brake upgrade, had issues bleeding that too. Power bleed is just a non starter on a brake caliper change. But I digress.

Fantastic Thread; read every word of it at least 3 times.
Its 2023 and you're still the only maverick to retrofit M callipers to the rear.

I'm in the UK and used parts are readily available at reasonable prices over here.

I really REALLY want to do this upgrade. You've inspired me!... but I lack any experience or knowhow on machining things.

Is there any chance I could buy a set of the rear calliper brackets and hub spacers from you?
I have a US address it can be sent to.

P.S. did you resolve the soft pedal issue?

 

[fmorelli]

Fantastic Thread; read every word of it at least 3 times.
Its 2023 and you're still the only maverick to retrofit M callipers to the rear.

I'm in the UK and used parts are readily available at reasonable prices over here.

I really REALLY want to do this upgrade. You've inspired me!... but I lack any experience or knowhow on machining things.

Is there any chance I could buy a set of the rear calliper brackets and hub spacers from you?
I have a US address it can be sent to.

P.S. did you resolve the soft pedal issue?

THanks for the kind words. You are in the UK ... the upgrade for you is PB Brakes. They have a great setup for the E89 Z4!

 

[Armando1969]

Fantastic Thread; read every word of it at least 3 times.
Its 2023 and you're still the only maverick to retrofit M callipers to the rear.

I'm in the UK and used parts are readily available at reasonable prices over here.

I really REALLY want to do this upgrade. You've inspired me!... but I lack any experience or knowhow on machining things.

Is there any chance I could buy a set of the rear calliper brackets and hub spacers from you?
I have a US address it can be sent to.

P.S. did you resolve the soft pedal issue?

I second What Fmorelli said, I have the rear big brake set from PB on my car myself. Great company to do business with and their product is very good.

 

[Mittu]

Would love rear PB brake kit, but its over £2000!
Ive already installed M callipers on the front. Just trying to figure out how to instal the rear set.

Rear discs for a range rover IV are within spec for the G30 M calliper. No alterations would be needed to calliper or brake pads.
Relatively cheap, only 50 quid starting price and readily available everywhere.
Rotors, callipers and pads tallying up to less than £500.
Just need calliper carrier brackets making... I'll knock on a few doors locally.

In the UK, German cars are by far the most common. Blink and you'll miss a dozen go by. Used parts are very affordable and easy to obtain.
But even then, the e89 is an uncommon car. I drive 2hrs in traffic everyday, and I probably only see 1 a week. There's more Bentleys than e89s', and rarely is it a 35is.

 

[Armando1969]

Would love rear PB brake kit, but its over £2000!
Ive already installed M callipers on the front. Just trying to figure out how to instal the rear set.

Rear discs for a range rover IV are within spec for the G30 M calliper. No alterations would be needed to calliper or brake pads.
Relatively cheap, only 50 quid starting price and readily available everywhere.
Rotors, callipers and pads tallying up to less than £500.
Just need calliper carrier brackets making... I'll knock on a few doors locally.

In the UK, German cars are by far the most common. Blink and you'll miss a dozen go by. Used parts are very affordable and easy to obtain.
But even then, the e89 is an uncommon car. I drive 2hrs in traffic everyday, and I probably only see 1 a week. There's more Bentleys than e89s', and rarely is it a 35is.

Hi Mittu,
I understand you reasons and reasoning, but I question that when you do the total cost calculation at the end, that it was cheaper. I hoop for you it will be, but reading Fmorelli's story I doubt it.
Enjoy your car
Gr Armando,

 

[fmorelli]

Hi Mittu,
I understand you reasons and reasoning, but I question that when you do the total cost calculation at the end, that it was cheaper. I hoop for you it will be, but reading Fmorelli's story I doubt it.
Enjoy your car
Gr Armando,

@Mittu tagging you as well.

The above comment is on point, in my view. It is not as simple as making a bracket, either. There was custom fitting work that was done to make it all happen. The goal was to solve the problem for my car, not to solve the issue as one would with a product. It was quite a bit of work, as well.

I would seriously suggest the PB route, unless others are now making electrohydraulic brake solutions for later model cars. It's not cheap, but my solution was hardly cheap in any dimension. I had my reasons for doing it this way, and doubt anyone factor that into their build. In my case, I wanted a factory look. Kind of ridiculous, I know, which is why I would not recommend it. Best of luck to you!

 

[Mittu]

Same here, Im only interested in a factory look. I don't want that track car high downforce look.
I'm trying to do this job on the cheap and so far I'm comfortably within budget.
Was trying to figure out disc and carrier bracket solution until I came across your epic write up.

Already bought a set of used G30 M sport callipers a couple months back with decent pads (£300), and can be had for as little as 200-250. A few years back they would've fetched a lot more, as the G30 had only been out a couple years.

I was going to follow in your footsteps. Those 345mm CSL discs look mean as hell, but they aren't cheap (£220-300/ disc).
Sites that allow searching by disc spec, only show the CSL ones, but some also came up with Land Rover/ Range Rover discs.

Used across half their models (Range Rover IV, Ranger Rover Sport, Discovery, Defender), making them readily available at low prices.
Available in 350 and 365mm; 25mm thick, 49.5mm height.

350mm start as low as £39/ disc and TRW/ Brembo discs are £62 (autodoc.co.uk).
365mm (for 20" rims) are £75 for Brembo and £114 for perforated Zimmerman.

Ive ordered a set. Total spend so far = £440.

Theyre never going to be as track worthy as the m3 CSL discs, but that's ok, I don't race. Besides, these blue M Sport brakes are their basic ones. If I were fitting full fat M brakes, then I wouldn't mind coughing up for high end discs.

Locally to me, there's a few machinist, welders, and car restoration shops. Hopefully I can have them knock out the calliper carriers.

Thanks for all your advice. Would not have been motivated to do this brake upgrade without reading your posts.