[TorBimmer]

I've seen a lot of confusion and misinformation in these forums, so lets clarify the requirements for the M-Performance Brake Kit on the G20 3 series!

Backstory
I recently installed M Performance Brakes on my North American 330i that used to have the base floating calipers. I learned a lot of things in the process.

After the upgrade, I ended up with annoyingly soft/mushy brake feel. Totally fine for daily road use, annoying for backroad driving, and inadequate for track use. The faster you go and the harder you press on the brakes, the softer they feel - not great! And yes, they were coded in properly.

How could these brakes feel so mushy? I've driven an M-Sport Brake equipped 330i and an M340i with the same M-Sport brakes - these cars had a consistently firm pedal and near-instant brake bite with minimal pedal travel. How could my car with M-Performance Brakes feel so different? I sought out for a solution. The answers are below.

As for why I made the upgrade?
1. They look great. The base floating calipers are a travesty - should be a crime that BMW does not include M-Sport brakes in the M-Sport package (they're a standalone option).
2. I wanted brakes that were capable of light to medium track use. Base floating calipers don't cut it. AP Racing kits or Brembo kits were twice the price of the M-Performance. From this perspective, it made sense.

Minimum Wheel Size Requirements for M-Performance Brake Kit
The g20 M Performance brakes will fit on SOME 18 inch wheels - that's why the official minimum is 18inch for the kit, but I think some dealers edit the description to 19inch to save themselves the trouble. It all depends on the barrel size and clearance.

Supported 18inch wheels (based on what I personally know)
BMW 796M - Part of the M-Performance catalog. Offered in Winter Tire packages and Summer Tire packages.
APEX VS-5RS 18inch - Check their fitment guide for more information


Master Cylinder and Brake Booster Requirements for M-Performance Brake Kit

Summary for g20 M Performance Brake Upgrade

US 330i with base brakes (grey floating calipers)

• New Master Cylinder: Not Required
• New Brake Booster: Technically not required, but you will benefit from an upgraded brake booster P/N: 34336889796

US 330i with M-Sport Brakes or M340i? - Direct Fit!

• New Master Cylinder: Not Required
• New Brake Booster: Not Required

EU/ASIA 320i/330i with base brakes (grey floating calipers)?

• New Master Cylinder: Yes, required!
• New Brake Booster: Yes, required!
  Your markets sell a version of the M-Performance Brake Kit that comes with the Master Cylinder+Brake Booster as a preassembled part. Get this one!

Detailed Explanation
While US 330i with base brakes don't technically need a brake booster (the m-perf brakes will work, but pedal feel will be soft and mushy), you will benefit from upgrading to the stronger brake booster offered in M-Sport Brake equipped cars (330i with M-Sport brake option or standard on M340i).

North American g20 3 series
Fortunately, all North American 3 series regardless of brake type have the same Master Cylinder. This may be the reason why BMW NA chose to not sell the M-Perf Brake Kit that comes with the additional Master Cylinder+Brake Booster part - because NA vehicles are already equipped with the better Master Cylinder. BUT, 330i with base brakes are equipped with the weaker brake booster and will suffer from an annoyingly soft/mushy brake pedal if paired with M-Perf Brake Kit.

All North American 3 series have the same Master Cylinder.

North American 330i Base Brakes (Floating Calipers) Brake Booster P/N: 34336889801
North American 330i M-Sport or M340i Brake Booster P/N: 34336889796


Europe/Asia g20 3 series
European or Asia market 320i/330i with the base floating caliper brakes are equipped with both a smaller Master Cylinder AND the weaker brake booster. This is why these markets sell a version of the M-Perf Brake Kit that comes with an additional Master Cylinder+Brake Booster part.

If you choose to install M-Perf Brakes on a EU/Asia base brake car without the upgraded Master Cylinder+Brake Booster, you will have an arguably dangerously soft brake pedal.


Additional Notes or Reading
These conclusions were made by analyzing part diagrams and part numbers on REALOEM and confirmed with the Shop Foreman at a BMW dealer.

For more information on the different g20 brake types, refer to below. Hopefully, they update their thread based on this post
https://www.bimmerworld.com/About-Us...rakes-G20-G22/

[Two3Series858]

TorBimmer I can't thank you enough for this info. Going from base brakes all the way to M-Perf. I see you recommend the brake booster. How many are needed? 1 total, or 4 (1 per wheel)?

Stupid question... you listed the part numbers for the base model brake booster and the M-Sport/Perf booster. I assume I need the latter for the upgrade...?

Man, you start thinking of an upgrade and someone comes along with the EXACT situation

[TorBimmer]

Originally Posted by Two3Series858

TorBimmer I can't thank you enough for this info. Going from base brakes all the way to M-Perf. I see you recommend the brake booster. How many are needed? 1 total, or 4 (1 per wheel)?

Stupid question... you listed the part numbers for the base model brake booster and the M-Sport/Perf booster. I assume I need the latter for the upgrade...?

Man, you start thinking of an upgrade and someone comes along with the EXACT situation

There's only one brake booster in the car. And yes, you need the M-Sport part. This is the one you'll need: https://www.getbmwparts.com/oem-part...er-34336889796

While you don't technically need need it, it will noticeably improve your brake feel. If you want even more improvement, switch to stainless steel brake lines.

Additional FYI, the M-Performance brake discs are loud. They're slotted AND dimpled, so that creates turbulance which results in a shhshhshh sound when you're cruising around. You can only hear it with the windows down.


But yeah, it would definitely be nice if there were mods who could sticky or sort these threads into a "Knowledge Base" section or a centralized how-to. It's difficult to find things...I'm still trying to figure out how to code ASD off and add the exhaust valve control menu...

[Two3Series858]

WHEW! Because 4 of those priced out to about $1800. Wifes ok with that small additional cost for 1.

The brake sound you describe... must be common to all M-Perf brakes then? That's what I'm drawing from your description. I wonder if that ends up being just slightly annoying or louder than one may like.

[RNigel]

Originally Posted by TorBimmer

I've seen a lot of confusion and misinformation in these forums, so lets clarify the requirements for the M-Performance Brake Kit on the G20 3 series!

Backstory
I recently installed M Performance Brakes on my North American 330i that used to have the base floating calipers. I learned a lot of things in the process.

After the upgrade, I ended up with annoyingly soft/mushy brake feel. Totally fine for daily road use, annoying for backroad driving, and inadequate for track use. The faster you go and the harder you press on the brakes, the softer they feel - not great! And yes, they were coded in properly.

How could these brakes feel so mushy? I've driven an M-Sport Brake equipped 330i and an M340i with the same M-Sport brakes - these cars had a consistently firm pedal and near-instant brake bite with minimal pedal travel. How could my car with M-Performance Brakes feel so different? I sought out for a solution. The answers are below.

As for why I made the upgrade?
1. They look great. The base floating calipers are a travesty - should be a crime that BMW does not include M-Sport brakes in the M-Sport package (they're a standalone option).
2. I wanted brakes that were capable of light to medium track use. Base floating calipers don't cut it. AP Racing kits or Brembo kits were twice the price of the M-Performance. From this perspective, it made sense.

Minimum Wheel Size Requirements for M-Performance Brake Kit
The g20 M Performance brakes will fit on SOME 18 inch wheels - that's why the official minimum is 18inch for the [...]

This was a fantastic read. Thank you so much for this info!

[TorBimmer]

Originally Posted by Two3Series858

WHEW! Because 4 of those priced out to about $1800. Wifes ok with that small additional cost for 1.

The brake sound you describe... must be common to all M-Perf brakes then? That's what I'm drawing from your description. I wonder if that ends up being just slightly annoying or louder than one may like.

It's common to any brakes that are not blank faced. So, slots, dimples or cross-drilled will all have unique noise patterns.

The dimples on the M-Perf are particularly noisy with the shhshhshh sound. I find it annoying, but I never cruise with the windows down so I don't care.

The cross-drilled rotors on the G80 M3 are noisy too, but it's a lower frequency helicopter kind of noise lol.

But my hearing is sensitive, so, YMMV

[Two3Series858]

TorBimmer Sorry... had a last follow up.
1 M-Performance Brake Kit 34-10-8-854-026
1 Brake Booster 34-33-6-889-796...
Any additional pieces required? The guys on the site say the Kit has everything I need, but with adding the Booster, I'd hate to not have the one or two things (a gasket, a bracket, a magic screw?) I need when I have my shop install. Thanks!

[Two3Series858]

I pulled the trigger on the Brake Kit and the Brake Booster. Next up is finding a good install price from a dealer on local shop. Leaning dealer for quality and piece of mind.

[SeattleLSB]

Did you try the coding first?

[kev01vfr]

Originally Posted by Two3Series858

TorBimmer Sorry... had a last follow up.
1 M-Performance Brake Kit 34-10-8-854-026
1 Brake Booster 34-33-6-889-796...
Any additional pieces required? The guys on the site say the Kit has everything I need, but with adding the Booster, I'd hate to not have the one or two things (a gasket, a bracket, a magic screw?) I need when I have my shop install. Thanks!

I just went out to check on these parts, they indicate they are no longer available. Any ideas?

[Two3Series858]

Originally Posted by kev01vfr

I just went out to check on these parts, they indicate they are no longer available. Any ideas?

They are very much available. I ordered the both from a BMW Parts Center out of NH. Both are also on Get BMW Parts. The booster has to be ordered from Germany but available. Who did you use?

[Two3Series858]

Originally Posted by SeattleLSB

Did you try the coding first?

If you're asking me, I haven't gotten the parts in the mail yet. But I will get the car coded during install. Apparently it must be done.

[kev01vfr]

Originally Posted by Two3Series858

They are very much available. I ordered the both from a BMW Parts Center out of NH. Both are also on Get BMW Parts. The booster has to be ordered from Germany but available. Who did you use?

Thanks for the recommendations, yes, I found it.

Thanks again, Kevin

[TorBimmer]

Originally Posted by Two3Series858

TorBimmer Sorry... had a last follow up.
1 M-Performance Brake Kit 34-10-8-854-026
1 Brake Booster 34-33-6-889-796...
Any additional pieces required? The guys on the site say the Kit has everything I need, but with adding the Booster, I'd hate to not have the one or two things (a gasket, a bracket, a magic screw?) I need when I have my shop install. Thanks!

My bad, I forgot to follow up on this!

I wasn't quoted for any additional parts. Just the brake booster itself, so I'm hoping that means nothing extra is needed for the installation.

I hope it goes well for you.

[Two3Series858]

Originally Posted by TorBimmer

My bad, I forgot to follow up on this!

I wasn't quoted for any additional parts. Just the brake booster itself, so I'm hoping that means nothing extra is needed for the installation.

I hope it goes well for you.

All good brother. Friday is the big day. I have the kit and booster.

[eagerbimmer]

Originally Posted by TorBimmer

EU/ASIA 320i/330i with base brakes (grey floating calipers)?

• New Master Cylinder: Yes, required!
• New Brake Booster: Yes, required!
  Your markets sell a version of the M-Performance Brake Kit that comes with the Master Cylinder+Brake Booster as a preassembled part. Get this one!

Europe/Asia g20 3 series
European or Asia market 320i/330i with the base floating caliper brakes are equipped with both a smaller Master Cylinder AND the weaker brake booster. This is why these markets sell a version of the M-Perf Brake Kit that comes with an additional Master Cylinder+Brake Booster part.

If you choose to install M-Perf Brakes on a EU/Asia base brake car without the upgraded Master Cylinder+Brake Booster, you will have an arguably dangerously soft brake pedal.

there are multiple m-performance brake kits p/n and it's quite confusing.
M Performance Brake Kit in Red
34-11-2-450-161/34-10-8-854-026 - i think this has no brake booster. Two3Series858 shared this too.
34-11-2-458-884/34-10-8-857-048 - looks like this has brake booster. the parts break down lists a booster though i cant find this p/n


i found a few places that can retrofit the bmw m performance brake kit but i think their kits come without the booster. im told it's extra charge for the booster (34-33-6-889-796 i hope)

but what about master cylinder, i see there are 2 parts? do i get both?
is this master cylinder the bigger one i should be getting?

Brake Master Cylinder Reservoir - BMW (34-33-6-889-802)


Master Cylinder - BMW (34-33-6-892-205)

[Two3Series858]

The two kits are for the two different sets of markets. Theres a North American market kit and there's a Euro/Asia/everybody else kit. The latter includes a Master Cylinder and Booster because those markets vehicles don't have the same MC and don't even have a BB installed.

The NA market vehicles ALL have the same MC and A booster, but the booster model is different depending on what model vehicle you have. I was not directed to purchase a different reservoir so I only got the kit and upgraded booster.

As you discovered, the kit model numbers have changed like all BMW parts tend to do. So info for the most recent NA kit still references the old NA kits info. I'm in that same boat right now with the dealership looking for the most updated install info.

[Two3Series858]

Install completed! The dealership techs had to bleed the system multiple times just as others had experienced. Not sure the reasoning why, but eventually they felt right enough to release the car. Maybe someone can unpack that. Bummer that my stock brake pads were damn near brand new.

The techs said they were aware of the brake booster issue and hoped I had one.

[eagerbimmer]

Originally Posted by Two3Series858

Install completed! The dealership techs had to bleed the system multiple times just as others had experienced. Not sure the reasoning why, but eventually they felt right enough to release the car. Maybe someone can unpack that. Bummer that my stock brake pads were damn near brand new.

The techs said they were aware of the brake booster issue and hoped I had one.

you were ready right? you had a new brake booster prepared for this moment lol. bruh im so excited for you... how is the whole driving feel now? what are you going to do with your stock brake kit? i figured no one is going to buy it so i dont know what im going to do with mine.

[Two3Series858]

Originally Posted by eagerbimmer

you were ready right? you had a new brake booster prepared for this moment lol. bruh im so excited for you... how is the whole driving feel now? what are you going to do with your stock brake kit? i figured no one is going to buy it so i dont know what im going to do with mine.

It is great! Exactly as described by others. I barely have to press the brakes and she comes to a nice, controlled stop. The front doesn't dip. Still taking it easy as I break them in. A little squeak here and there, but understandable. Probably gonna clean up the originals and save them. You should hold onto them just in case!

[TorBimmer]

eagerbimmer
You cannot find the 29689220301 part number because it is unique to the M-Performance Brake Kit and not offered standalone. This part is a unique pre-assembled kit of the Master Cylinder + Reservoir + Brake Booster together. It is only offered in non-NA markets in the M-Perf Brake Kit+Master Cylinder kit. You will need this kit if you have a EU 318i (or diesel equivalent).

If you have an EU 330i or 330e with the base floating calipers, I'm not sure which kit you need, you'll need to confirm which master cylinder and which brake booster its equipped with.

Two3Series858
Congrats on the upgrade! Glad the brakes are feeling good. It's a night and day difference with the right brake booster.

[GeorgeRSA]

Hi Folks

I upgraded my 318i brakes to the M Sport brakes and it had spongy brakes even after proper bleeding by dealership. Purchased and installed the M Performance brake booster and master cylinder.

I only bled the FL caliper inner fluid pipe and RL caliper as the car had a brake fluid flush at dealership 2 weeks back. Pumped the brake pedal until I got fluid release without bubbles on both calipers (2 man job without bleeding kit). Brake pedal distance and responsiveness is akin to a stock 330i with M Sport brakes (Tested). The brakes are very responsive now. Huge difference with the proper brake booster & master cylinder.