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The Comprehensive E46 Brake Upgrade Guide

198K views 92 replies 31 participants last post by  phongus 
#1 · (Edited by Moderator)
First off let me say that this thread is not meant to bash anyone or anything, it is meant purely as a reference. Seeing as I do not own every single E46 ever made I cannot 100% guarantee a single solution will work for you, the best I can do is cross reference part numbers. Please avoid filling this thread with questions like "Why would you want to do _ when you can do _?" as well as any other non related topics. If you notice an error please let me know so I can correct it. I will not be making specific pad, rotor, or fluid recommendations because everyone uses their car differently. Track pads are probably not ideal for someone who dailies their car, and some people prefer one style of rotor to another. I will do my best to include links where applicable. The last thing I have to say is PLEASE BUY QUALITY PARTS. Yes, eBay rotors and pads may get you down the road but it's your life, your car, and your money. Let's get started!

For Non-M Cars Only!

Stage 1 - For All Cars


  • New pads and rotors meant for how you drive your car (street, track, autocross, etc...).
  • Flush the system with DOT 4 or higher fluid.
  • Replace rotor screws anytime you remove old ones. They're so cheap it's not worth the hassle of having old, stripped screws.
  • Replace wear sensor. Not needed every time you touch the brakes, but it is a good thing to consider depending on the age and mileage of your sensor.
  • (Optional) Stainless Steel Brake Lines. Not needed, but will give you a slightly improved pedal feel.
  • (Optional) Speed Bleeders. Not needed, but allows the brakes to be bled quickly and you don't need a second person do do them. Worth every penny - http://www.speedbleeder.com/

Stage 2: 330i/ci/xi Upgrade - For 323/325/328 Cars

17" Wheels required. Front rotor size: 325mmx25mm. Rear rotor size: 320mmx22mm.



This process is the same as a standard brake service, however instead of putting your old parts on you replace them with parts from a 330i/ci/xi.

  • 330 Calipers
  • 330 Caliper Carriers
  • 330 Pads
  • 330 Rotors
  • 325xi/330/M3 Wear Sensor - The part number is different between the 325i/ci and the 330. The part number is the same between the 325xi and the 330. I cannot confirm if it is indeed different, but again it is good to replace anyways.
  • Flush the system with DOT 4 or higher fluid
  • 325/330 Rotor Screws
  • (Optional) When doing the rear, you will lose the parking brake functionality unless you swap the rear trailing arms and hub assembly from a 330 because the parking brake shoes are larger. With a 325xi you already have the larger 330 sized parking brake so this does not apply to you.
  • 330 Stainless Steel Brake Lines. Not needed, but will give you a slightly improved pedal feel.
  • (Optional) 330 Speed Bleeders. Not needed, but allows the brakes to be bled quickly and you don't need a second person do do them. Worth every penny - http://www.speedbleeder.com/

Stage 2.5: M3 Upgrade - For All Non-M Cars

17" Wheels (M3 Rotors) -18" Wheels (CSL Rotors) required. Front rotor size: 325mmx28mm (M3) - 345x28mm (CSL). Rear rotor size:327x20mm.

This process is similar to the 330 upgrade, but requires some machining.





  • M3 Calipers
  • M3 Caliper Carriers - SPINDLE MOUNTING TABS MUST BE MACHINED 6.35mm
  • M3 Pads
  • M3 Rotors
  • 325xi/330/M3 Wear Sensor
  • Flush the system with DOT 4 or higher fluid
  • M3 Rotor Screws
  • (Optional) When doing the rear, you may have to swap the entire rear subframe/differential assembly from an M3. You may only need the 330 trailing arms and hub assembly because the 330 and the M3 share the same parking brake, but there is no solid information about this available.
  • M3 Stainless Steel Brake Lines. Not needed, but will give you a slightly improved pedal feel.
  • (Optional) M3 Speed Bleeders. Not needed, but allows the brakes to be bled quickly and you don't need a second person do do them. Worth every penny - http://www.speedbleeder.com/

Stage 3: Porsche 996 Upgrade - For All Non-M Cars

17" Wheels (M3 Rotors) -18" Wheels (CSL Rotors) required with +35mm offset or lower. Front rotor size: 325mmx28mm (M3) - 345x28mm (CSL). Rear rotor size:327x20mm.

This process is similar to the 330 upgrade, but requires some grinding/machining and minor wiring. The wear sensor wires must be spliced between the 996 sensor (pad side) and the E46 sensor (vehicle side).





  • Porsche 996 Front Calipers (PN 996.351.425, 996.351.426) - Machine mounting bosses 12mm for use with M3 rotors, do not machine for use with CSL rotors
  • RallyRoad Front Caliper Brackets - Rally Road | RallyRoad.net
  • Porsche 996 Rear Calipers (PN 996.352.421 996.352.422)
  • RallyRoad Rear Caliper Brackets - Rally Road | RallyRoad.net
  • Porsche 996 Pads
  • Porsche 996 Pad Shims - These prevent the brakes from squaking like many people complain about. Not needed, but cheap enough to not skip over.
  • RallyRoad Front Brake Lines - Rally Road | RallyRoad.net
  • RallyRoad Rear Brake Lines - Rally Road | RallyRoad.net
  • M3/CSL Rotors - Read above
  • 325xi/330/M3 Wear Sensor
  • 996 Wear Sensor
  • Flush the system with DOT 4 or higher fluid
  • M3 Rotor Screws
  • Grind casting marks on the spindle - This will vary between vehicles. On some (most?) you will need to grind away the casting lines on the spindle so that the caliper bracket sits flush. It is nothing major, but it does need to be noted.
  • (Optional) When doing the rear, you will lose the parking brake functionality unless you swap the rear trailing arms and hub assembly from a 330 because the parking brake shoes are larger. With a 325xi you already have the larger 330 sized parking brake so this does not apply to you.
  • (Optional) 996 Speed Bleeders. Not needed, but allows the brakes to be bled quickly and you don't need a second person do do them. Worth every penny - http://www.speedbleeder.com/

Stage 4: 135i Upgrade - For All Non-M Cars

17" Wheels required with +35mm offset or lower. Front rotor size: 325mmx25mm (unless using ECS kit or custom brackets). Rear rotor size:327x20mm.

This process is similar to the 330 upgrade, but requires some cutting and minor wiring. The wear sensor wires must be spliced between the 135i sensor (pad side) and the E46 sensor (vehicle side).





  • 135i Calipers
  • 135i Caliper Brackets. Stock caliper brackets will leave a little bit of pad overhang. Not 100% ideal, but will work fine. Currently the only solution is to buy the whole kit from ECS tuning or have custom brackets made.
  • 135i Pads
  • (Unsure) Extended Front 135i Brake Lines - Stock 135i lines MAY work. Not sure on where to get these other than having a set custom made, need to be 600mm long. Front 135i lines can be used on the rear to possibly solve the rear length issue if needed.
  • 330 Front Rotors
  • M3 Rear Rotors
  • 325xi/330/M3 Wear Sensor
  • 135i Wear Sensor
  • Flush the system with DOT 4 or higher fluid
  • 330 Rotor Screws
  • M3 Rotor Screws
  • Trim/replace rear dust shield - In order to clear the M3 rotor on the dust shield must be trimmed or replaced with an M3 shield.
  • (Optional) When doing the rear, you will lose the parking brake functionality unless you swap the rear trailing arms and hub assembly from a 330 because the parking brake shoes are larger. With a 325xi you already have the larger 330 sized parking brake so this does not apply to you.
  • (Optional) 135i Speed Bleeders. Not needed, but allows the brakes to be bled quickly and you don't need a second person do do them. Worth every penny - http://www.speedbleeder.com/
  • (Optional) The stock 135i caliper pistons are prone to cracking under hard (read:track day bro) use. Replace with a quality set of pistons.

I will update this thread as I find time. I hope this is a good start for some of you, and I hope it's good enough to not be deleted right away. Every other forum I've been on has had guides like this posted, but I have not found very many on this forum. PLEASE SEND OR POST PICTURES OF YOUR BRAKES!!!
 
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#36 · (Edited)
I asked the same question on an older thread
' rear axle differences early 01 vs later '

hoping someone would get back to me. Member Evnmopwr replied with the following :

When i checked mine, the Splines on the 325i Shafts were the same as the Spline groves on the 330i hubs...

" I have a Preface lift 325i touring. and the rear trailing arms were from a Facelift 330i...

I was forced to change the Prop shaft, Diff etc because i installed the 330i 6 speed manual

But i remember it working.. The only thing Diff on the trailing arms are the Brakes size"

As you can imagine this is the glimmer of hope im reaching for.. purely in the interest of education and clarity ( im not in anyway suggesting your wrong or misinformed ) could you explain how you came to your conclusion please?
 
#41 ·
So I’m gong to need brakes sometime this year

I’d like to put on drilled rotors for the look. I don’t track or do canyons.

What’s the consensus on drilled? Did they solve the cracking issues?

If I install Eline (Chinese) from Amazon will they last 50k miles? Or will I have to redo it in 20k?

I put brakes on so seldom I don’t even know what the industry standards are.

Thanks.


Sent from my iPhone using E46Fanatics
 
#50 ·
Anyone noticed that rear calipers are different between 330i and 330xi\xd ? Xi\xd calipers are 34216768423\34216768424 , and RWD calipers are 34216765883\34216765884

https://www.realoem.com/bmw/enUS/partxref?id=EV53-USA-06-2002-E46-BMW-330i&mg=34&sg=10&diagId=34_1013&q=34216765883&series=E46 RWD 42\22
https://www.realoem.com/bmw/enUS/partxref?id=EW53-USA-06-2002-E46-BMW-330xi&mg=34&sg=10&diagId=34_1013&q=34216768423&series=E46 AWD 40\22

Interesting enough - both 40\22 and 42\22 calipers are listed as proper rear calipers for Euro 325i :eek:

So is it any real life difference between 330i and 330xi? I'm planning to rebuild my calipers\buy rebuilt ones, and I'm curious about if installing RWD calipers will get any measurable pros\cons
 
#51 ·
I picked up a set of xi trailing arms Friday in anticipation of doing this swap and got to wondering if I should bother with the intermediary step of using 330i calipers and rotors or if I should go straight to where I'll ultimately end up, which is the 996 calipers on Rally Road brackets and CSL rotors. In researching that I noticed that Rally Road suggests using E38 750i rear rotors as that gets you the 327x20 rotor size, but retains the 325i's 6-1/2" parking brake drum. Does anybody have any input to further confirm this? I was kind of surprised that I hadn't seen this as an option anywhere else.

I'm still going to use the xi RTAs that I got as it will be much easier to clean them up and have them rebuilt and ready to go when it comes time to do my swap, but I thought that it might deserve mention in this already great thread.
 
#52 · (Edited)
I think the Xi uses the 185mm parking brake drum, same as the 330. The 325 like mine uses the 160mm parking brake drum and the 750i info is something I have not heard of either. 160mm is so small, I can't imagine the 750i using that size but lets find out!

The parking brake is something I still need to deal with on my BBK. Some have made 12.5mm spacers pressed and pinned into the rotor drums and some have fabricated special shoes with a set of 325 and 330 shoes together.

The 750i rotor sounds interesting for sure. Can you provide a link to the Rally Road 750i rotor suggestion info? I looked on their site and can't find it
 
#55 ·
Alright, I've got that sorted. Rally Road was referring to using the 750i rotors when doing the 996 brake upgrade on your E36 M3 as they have a 334x32 dimension with the same 180mm parking brake drum as the E36 M3. Unfortunately this won't work for the E46 325i's 160mm parking brake, so the 330i trailing arm swap is completely necessary unless you want to sleeve your parking brake drum or use custom pads.
 
#57 ·
#61 · (Edited)
Finally got around to fabricating 325 to M3 rotors parking brake shoes today. Pretty straight forward. We simply drew the circumferences of the two sizes, cut the shoe off the 325 parts and cut the 330 shoe leaving .512" from the shoe. Welded them up and installed everything back. Working parking brake and BBK completed. :thumbsup:

Stencil drawn and shoes cut.



Tacked together for test fit.



Fully welded in 3 1" welds (outsides in front and center in rear) and installed

 

Attachments

#75 ·
Good list. Good choices.
I’d add a pair of anti-rattle clips (optional, but more likely to be rusted than the circlips) and two hub nuts. Shouldn’t reuse the hub nuts.

anti-rattle clip 34216753675
Hub nut 33411133785

Consider buying 3-4 of these clips - they get brittle with age and either have broken or will break as you are running the speed sensor and brake wear sensor leads

34521164653

I would strongly recommend replacing at least the large transverse differential bushing. You will have good access to the differential after removing the axles and it likely needs replacing.

Last suggestion is only a suggestion. Most of the e46 suspension nuts are single use - self-locking. The recommendation is replace after removing. You can also use blue Loctite (I get new nuts, but I am compulsive).
 
#76 ·
Good list. Good choices.
I’d add a pair of anti-rattle clips (optional, but more likely to be rusted than the circlips) and two hub nuts. Shouldn’t reuse the hub nuts.

anti-rattle clip 34216753675
Hub nut 33411133785

Consider buying 3-4 of these clips - they get brittle with age and either have broken or will break as you are running the speed sensor and brake wear sensor leads

34521164653

I would strongly recommend replacing at least the large transverse differential bushing. You will have good access to the differential after removing the axles and it likely needs replacing.
Seems like as soon as I posted it; It hit me that I forgot to add Axle Nuts!
As for those things you mentioned, wasn't aware! Much appreciated.

For the Differential Bushings should I go for something like this?


Also; Updated document!

 
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