Install of F80 M3/4 Front and Rear Brakes, SLG brackets, ER Brake Lines

[houtan]

I have been working on a brake upgrade to my 135i and wanted to share my experience. I still haven’t driven my car with the new upgrades, but I am really happy with the results so far and am at a good point to share some information.

As with most of the modifications to my car, I didn’t “need” new brakes, but they were always one area I wanted to upgrade. Brake upgrades are usually very expensive though, so they always got pushed down the priority list, to other expensive upgrades. However, one option, the F80 brakes, seemed to be a cost effective and worthwhile upgrade so that became the most viable option for me.

I have been eyeing F80 brake sets for sale on the internet for a couple of years, but I was hesitant to make a purchase because I couldn’t use the rears. Then I heard about a company called Seems Legit Garage (SLG) and a bracket they make to get the rear f80 rotors to work with stock 135i hubs. After verifying the e brake works (about a 1/8” of the shoes doesn’t contact the rotor hat, which is completely acceptable to me.), my desire to buy an F80 brake set became more serious.

Long story short, I got an absolutely killer deal on a set of calipers, pads, and rotors that were literally brand new, ordered my brackets from SLG, and ER brake lines from N54tuning, and the project began.

The front caliper install and compatibility is well documented (

), but there is very little on the rear caliper install so I will share some additional information for that part of the installation. I am using the stock 135i master cylinder for now. Per SLG, there are no issues in their car using the stock master cylinder, so I am doing the same.

The specs on the F80 M3/M4 standards brakes are:
Rotors:
Front 380x 30 mm
Rear 370 x 24 mm

Calipers:
Front: 4 piston
Rear: 2 piston

My other requirement on a brake upgrade was being able to use 18” wheels. Not all wheels will work, but the Apex EC7 has been verified to clear so that is what I am going with.

Finally, I upgraded to ER stainless steel brake lines “while I was in there”. The fitment was perfect and the quality was top notch as well.

Front Brakes-
The main unknown for me on the front was what I wanted to do with the dust shield. One member, fe1rx, made custom pieces to protect suspension components which can be seen here (fe1rx AP Racing BBK Designed and Installed). Another site recommended removing them completely (Do I need brake ducts on my track car? | Essex Parts Services, Inc.). I stuck to the education I got from the @fe1rx thread and ended up trying to mimic the same thing. Of course, mine is not even close to as cool or good, but hey, I tried! Having said that, only minor trimming of the lower dust shield is required to get the caliper to fit which is easily accomplished with a set of tin snips.

As you will see in the pictures, fitment and alignment of the caliper and pads are perfect.

Front dust shield stock:


Front dust shield min required cut to fit caliper:



My feeble attempt to mimic @fe1rx:



Caliper with SLG bracket:


Final install / fitment:



Rear Brake-
Ohhh man, the rears had me worried. The initial test fitment showed getting the caliper to fit wasn’t even close. It was clear a lot more of the dust shield would need to be removed compared to the front and even after that, it seemed the brake shoes would be in the way. After a phone call to SLG (which by the way actually picks up their phone and returns VM/emails, which is awesome), I was able to confirm I need to cut much more than the front and the caliper will fit.

My tools of choice were tin snips and a Dremel with cut off, grinding, and sanding heads. I slowly cut away the dust shield for both the rotor and e-brake, and in a short amount of time I had everything fitting great.

The e-brake shoe barely clears the caliper and SLG confirmed everything is correct. I tested the e-brake as well and it operated normally, however, I decided to shave a small section to give more clearance.

One thing to note on the rear is the rotor screw hole does not line up with the 1er hub. This isn’t a safety issue so I am fine with it, but keep that in mind. Also, as I mentioned earlier, a small portion of the brake shoe doesn’t contact the rotor hat which looks to be about an 1/8 of an inch and should not impact functionality of the e-brake.

Final fitment of the caliper and pads is perfect in relation to the rotor.

Factory dust shield:


Modified dust shield with caliper:


E-brake shoe offset to F80 rotor hat:


E-brake shoe clearance to caliper:


E-brake shoe shave for additional clearance (personal preference):


Brake caliper with SLG bracket:


Final install / fitment:



ER brake lines-
The ER brake line install went without a hitch. Quality and fitment are perfect. The only recommendation I have, which I got from an @fe1rx thread, is get the Rapco RA716 tool if you are doing the upper rear lines by the subframe. I have no clue how anyone got those lines installed without it and it made that part of the install very easy. Took me 20 minutes max.

Rapco tool:



ER line Front:



ER line Rear:



Wide angle shot ��:


After everything was installed I bled the brakes with my motive pressure bleeder to get the air out, then I did another bleed using ISTA. Hopefully that got all of the air out of the entire system.

That’s all I have for now! I will update how everything is working once I am back on the road. Hopefully some time next week.

Update: 12MAR2022

Wheels came in and i did a quick test fit. Everything clears on the front and rear. Whew

Front:




Rear:



Update: 14Mar2022

Wheels and tires are on. Tires are Federal fz201 M with 255/35 fr, 265/35 rear. Fronts fit with no spacers.

Brakes also feel awesome. I didn’t brake hard but in normal driving everything felt great. Pedal feels firm and normal.

[CalvinNismo]

Looks great houtan! I've just bought some F8X calipers because I failed to make my 135i rear calipers work with M3 rear knuckles. (I attempted to use E46 M3 rear discs as they match the pad height of the 135i caliper, but it's not possible to get the caliper close enough in.)

I'm having to buy new wheels though, as you've said EC-7's fit no problem. ARC-8's need a good size spacer and are crazy tight on the barrel at the front. My friend is in the middle of doing this Seems Legit swap on his 135i at the moment and has both sets of wheels.

[houtan]

Originally Posted by CalvinNismo

Looks great houtan! I've just bought some F8X calipers because I failed to make my 135i rear calipers work with M3 rear knuckles. (I attempted to use E46 M3 rear discs as they match the pad height of the 135i caliper, but it's not possible to get the caliper close enough in.)

I'm having to buy new wheels though, as you've said EC-7's fit no problem. ARC-8's need a good size spacer and are crazy tight on the barrel at the front. My friend is in the middle of doing this Seems Legit swap on his 135i at the moment and has both sets of wheels.

Thank you! Just updated the main post with wheels installed.

[mad1stgen]

Can you share the wheel specs ?
Stock 1er fenders/quarters ?
Thank you.

[houtan]

Originally Posted by mad1stgen

Can you share the wheel specs ?
Stock 1er fenders/quarters ?
Thank you.

Yeah sure. Apex ec7s.

Front: 18x8.5 et45/ federal fz201 255 35
Rear: 18x9.5 et 58/ federal fz201 265 35

TC Kline coilovers. Stock fenders. My front fenders are rolled and the plastic bumper tab is shaved for additional clearance. M3 arms in front. 3.5ish degrees camber. No spacers needed but I put a 5mm spacer on the front to push the wheel out.

[Nikkosan]

Hey!
Did you changed the rear wheel hub?
The first few pix shows worn, and cone shaped, the end pix are flat and brand new…

[houtan]

Originally Posted by Nikkosan

Hey!
Did you changed the rear wheel hub?
The first few pix shows worn, and cone shaped, the end pix are flat and brand new…

They look good right?! I didn’t think anyone would notice but I was really impressed with how they turned out. Those are in fact the same, original, hubs.

After a couple of YouTube trainings, I cleaned them with a wire wheel mounted to a drill, a hand held wire brush, and a little bit of brake cleaner. After they seemed clean enough, I put a really thin coat of anti seize on them to help prevent the rusting from occurring again.

[Nikkosan]

Awesome job, I just wondering, that after instalation my brake caliper and disc didn’t line up. There is a 5mm gap between the hub and disc after aligned with the caliper. I might have to change hub after all.

[houtan]

Yeah you must not have factory 135i hubs. I can confirm they align perfectly on factory hubs so if you switch to that you should be in business.

[mwpa71]

Gday

did the arc 8's work?

[houtan]

Originally Posted by mwpa71

Gday

did the arc 8's work?

Hey there. It depends. At some point I believe Apex revised the barrel design to be similar to the EC7, which improved brake clearance. I found that out the hard way when I tried to install my ARC-8s and they wouldn’t clear the front. The current ARC8s for sale should fit, but you may need a small spacer. Apex could only confirm the EC7 would fit without a spacer so I went that route. Having said that, I ended up putting a spacer on anyway because I had a lot of clearance to the fender. Hope that helps.

[Expert@ApexWheels]

Originally Posted by houtan

Hey there. It depends. At some point I believe Apex revised the barrel design to be similar to the EC7, which improved brake clearance. I found that out the hard way when I tried to install my ARC-8s and they wouldn’t clear the front. The current ARC8s for sale should fit, but you may need a small spacer. Apex could only confirm the EC7 would fit without a spacer so I went that route. Having said that, I ended up putting a spacer on anyway because I had a lot of clearance to the fender. Hope that helps.

The revision is a bit more complicated than that. Our Profile 3 ARC-8s were the wheels that were revised (ie 18x9 ET30, 18x9.5 et35/22, 18x10 ET25) for better barrel clearance. The profile 1 ARC-8s (18x8.5 ET38/45, 18x9 ET42, 18x9.5 et58) are still on the original barrel specification, but the drop well location on the profile 1 ARC-8s is a bit better for these conversions (in some cases). The EC-7 is still definitely a better wheel for this conversion though because of the spoke shape.

-Tom

[houtan]

Originally Posted by Expert@ApexRaceParts

The revision is a bit more complicated than that. Our Profile 3 ARC-8s were the wheels that were revised (ie 18x9 ET30, 18x9.5 et35/22, 18x10 ET25) for better barrel clearance. The profile 1 ARC-8s (18x8.5 ET38/45, 18x9 ET42, 18x9.5 et58) are still on the original barrel specification, but the drop well location on the profile 1 ARC-8s is a bit better for these conversions (in some cases). The EC-7 is still definitely a better wheel for this conversion though because of the spoke shape.

-Tom

Great information and thanks for taking the time to clarify. Appreciate it.

[mwpa71]

G'day hoots. Re arc 8. Sorry mate I missed your response only just saw this. Could you confirm that you had barrel size or spoke/offset issues? and what offset arc 8s on the front.? Thanks mate appreciate it

[mwpa71]

Originally Posted by CalvinNismo

Looks great houtan! I've just bought some F8X calipers because I failed to make my 135i rear calipers work with M3 rear knuckles. (I attempted to use E46 M3 rear discs as they match the pad height of the 135i caliper, but it's not possible to get the caliper close enough in.)

I'm having to buy new wheels though, as you've said EC-7's fit no problem. ARC-8's need a good size spacer and are crazy tight on the barrel at the front. My friend is in the middle of doing this Seems Legit swap on his 135i at the moment and has both sets of wheels.

G'day Mate. Did your friend get the arc 8 to fit ok without issues?

[CalvinNismo]

Originally Posted by mwpa71

G'day Mate. Did your friend get the arc 8 to fit ok without issues?

On the front a 6mm spacer clears just, but it's crazy close to both the barrel and spokes. The rear is fine for both front and rear wheels. Front being an 18x8.5 ET45 ARC-8 and rear being an 18x9.5 ET58 ARC-8. The EC-7 are definitely an easier fit if you haven't already got the ARC-8's!

[houtan]

Originally Posted by mwpa71

G'day hoots. Re arc 8. Sorry mate I missed your response only just saw this. Could you confirm that you had barrel size or spoke/offset issues? and what offset arc 8s on the front.? Thanks mate appreciate it

I was having an issue with the barrel on my ARC8s. The size in front was 18 x 8.5” et 45. My ec7s, same size, fit with no spacer but I put a 5mm spacer on to move my wheel out since i had the clearance.

[mwpa71]

Thanks Mate. Doers it touch barrel with spacer? Or just super close?

[mwpa71]

Originally Posted by CalvinNismo

On the front a 6mm spacer clears just, but it's crazy close to both the barrel and spokes. The rear is fine for both front and rear wheels. Front being an 18x8.5 ET45 ARC-8 and rear being an 18x9.5 ET58 ARC-8. The EC-7 are definitely an easier fit if you haven't already got the ARC-8's!

Thanks mate for the speedy reply! I already have arc8s 45et. I have an 8mm spacer fitted currently.. I suspect 8mm will provide better spoke clearance...??. When you say tight barrel fit....how close? Cheers

[CalvinNismo]

Originally Posted by mwpa71

Thanks mate for the speedy reply! I already have arc8s 45et. I have an 8mm spacer fitted currently.. I suspect 8mm will provide better spoke clearance...??. When you say tight barrel fit....how close? Cheers

8mm will definitely be better! You need to either remove the OEM pad weights or buy front pads that come without them and then the casting ridges on the upper and lower extremes of the front caliper could do with 'massaging'.

[mwpa71]

Originally Posted by CalvinNismo

8mm will definitely be better! You need to either remove the OEM pad weights or buy front pads that come without them and then the casting ridges on the upper and lower extremes of the front caliper could do with 'massaging'.

Thanks mate. Appreciate the tips!

[houtan]

Originally Posted by mwpa71

Thanks Mate. Doers it touch barrel with spacer? Or just super close?

For me it hit the barrel. As Calvin posted, I would of had to massage the calipers a little (sand them down basically) but didn’t want to do that so I went with the ec7s.