Wednesday 22 April 2020

Project: F8x M4/M3 Brake Caliper/Rotor Retrofit Guide to E9x M3 - Using OEM Parts

I've been getting a lot of questions about my F8x M4/M3 brake upgrade, so I thought I'd give an overview on how it is done and what parts are required. This is not meant to be a step by step DIY but a guide on how it's done since it's really pretty simple with the right parts.

They can also be done using F8x CCB setup or M2 Comp parts as well.

This part list assumes you will be using E9x M3 wheel bearings and F8x standard steel brake calipers (Blue). While CCB or M2 Comp setups are possible, some of the parts below may differ. This is a good time to install new wheel bearings as preventative maintenance, especially if you have over 100k on your current ones. They are fairly inexpensive and FCP Euro offers lifetime warranty on all their parts.

If you plan to use F8x M3/4 wheel bearings, you'll need the f8x wheel bearing bolts, not the ones listed below. Additionally you'll need M14 wheel hardware and unless you plan to do the rear hub conversion also, you'll have unmatched wheel hardware front vs rear. But it is an upgrade option that some heavy track cars may benefit from with the larger M14 hardware. 

Part list:

  • F8x Calipers and Rotors/Pads
  • F8x Spindles
    • Right: 31212284002
    • Left: 31212284001
  • 4x M12 Flat washers, ideally around 2mm thickness each. 4mm total on each bolt to center the caliper on the rotor. 
  • F8x dust shields, you can cut trim the e9x ones. 
      • (also not a bad time to do brake ducting with a custom backing plate if you wanted to go that route) 
  • Wheel bearing bolts (one time use)
    • 31206783065 - M12X1.5X45 - (x8 - 4 per wheel bearing)
      • These bolts are required because the f8x carrier has a ball seat vs e9x which is flat
      • These are not the ones from an f8x since the f8x wheel bearings are a different thread pitch, I ordered these ones new from FCP Euro.
  • New wheel bearings are recommended as preventative maintainence, but you can reuse
  • New Brake lines are recommended, I went with E9x M3 Stainless stain lines from FCP Euro
  • Also included are new caliper bolts but those aren't required and you can reuse the stock e9x ones.
  • Finally, you need to decide how to handle the ABS sensors. Since the F8x sensor location is slightly different requiring you to change the orientation of the E9x ones to read correctly. 
      • Some have cut the e9x ones and created a holder out of metal.
      • Using the abs live obd2 reader, I was able to get the sensor to read correctly in this position (cut portion facing towards the outside center of the hub)
      • Eventually I bought 2 F8x sensors and spliced them into the E9x connectors and they worked perfectly and I was happier with that solution but both will work

Once you have all the parts together. We can get started. 
  1. Remove Wheels, calipers, rotors, dust shields. 
  2. I recommend removing the wheel bearings with the carrier/spindle still attached because the bolts are torqued pretty tight. 
  3. Remove the wheel bearing, then detach the control arms and tie-rod.
  4. Remove carrier/spindle
  5. Mount f8x carrier/spindle
  6. Attach wheel bearing, control arms, tie-rod, rotors, calipers, etc. Re-attach f8x dust shields or modify e9x ones before you mount the rotors/calipers (obviously). Install new brake lines if you planned to.
  7. Attach the wheel sensor and you should be done the fronts.
Rear Brakes
  1. Easier than the front, remove calipers, rotor.
  2. Trim dust shield or install f8x ones.
  3. Mount f8x rotors
  4. Mount f8x calipers, using 2mm washer(s) on each bolt between the caliper and mounting hole to center the caliper on the rotor. Confirm the caliper bolts engage fully. Use of Red Loctite is recommended
  5. Attach e9x or f8x brake lines, or stainless steel.

Finally you'll need to bleed the brakes. I recommend using ISTA/INPA to do the ABS bleeding procedure otherwise you may not get a firm pedal. I initially did not do the abs bleeding procedure and had a slightly soft pedal, once I did the abs bleeding procedure the pedal firmed up and felt much better. 

Lastly, get an alignment, re-adjust height if you have coil-overs. The f8x spindles add about 4mm of height and some camber. I had coil-overs so I re-set my height and got the car aligned to my specs.

That's it, enjoy your new brake setup. 

Note: Double check your wheels will clear the brakes. 18" Apex Arc8 wheels will not clear M4 brakes, some other 18s may not also.  

My Bimmerworld TA5R in 18x10 et25 do clear M4 brakes and will be used as my track setup. 


  1. There are thousands of brake pads, brake calipers, cylinders and axle parts in online parts store Parts catalog, parts manuals and service manuals are available in handbook
    Check this out.

  2. could you help me retro fit 2016 m3 or 4 brakes to my new M2C?

  3. Do you need the spindle for the rear too? I just picked up rear rotors,calipers and spindles but not sure if it requires all that.

  4. Hi i have just fitted front F80 rotors and calipers, could you get in touch with me as i have a few questions that i hoped you could help with

  5. Can you give me an information about washers for rear caliper? how thick is it?


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