Rear brake recommendation - 128i M Sport

[racer_951]

I bought a low mileage (38k miles) 128 M Sport in January this year. Even with low mileage, the suspension is shot. I tracked it a couple of times to figure out what areas this 128i needs improvements.

For brake, I bought a set of 135i front brakes. Currently running Hawk HP plus pads. I’m running stock rear brake with stock pads. The rear calipers have some rust on the surface but function fine. I’m looking at upgrading my rear brakes. I was thinking about replacing my rear brakes with 135i rear but I was told it isn’t a direct bold on. Some mods are required for the parking brake to work.

What do you guys recommend?

[racer_951]

By the way, the Hawk pads came with the setup when I bought it. I plan to switch to Ferodo DS2500 pads. Never tried them but heard good things about these pads.

[racer_951]

I also want to clarify my goals of the rear brake next step.

1. Functional - for track duty.
2. Aesthetic- my rear brakes look rusty. I went to harbor freight and got me a wire brush for my power drill to tackle the surface rust on the rear calipers. Since I already have 135i front brakes, a complete set with 135i rears seems like a good idea from aesthetic perspective.

So far, I haven’t experienced any brake issues after I installed the 135i front brakes. But I also didn’t want to push the car so hard in it’s current state with totally worn out shocks, bushings etc. plus stock rear brake with very old stock pads. Down the road, after I finish the coilovers, f/r control arms, and solid rsfb, I will push my 128i a bit more harder. We’ll see what’s next with the brake department.

[edycol]

Are you sure Brembo calipers don't fit back? I can see issue with parking brake shoes being smaller on 128. But, I am not sure that is the case. I know they fit E90 328 xDrive so that is why I think parking brake shows are smaller on 128.
One thing you want to consider if you are going to track that car is upgraded pistons on front calipers. Pistons on those 6 pots are known to crack on track.
If shoes are smaller, there is modification. On E90 forum there is good thread about modifying shoes to fit 324X22mm rotor. Calipers are bolt on.

[Suprgnat]

Originally Posted by edycol

Are you sure Brembo calipers don't fit back? I can see issue with parking brake shoes being smaller on 128. But, I am not sure that is the case. I know they fit E90 328 xDrive so that is why I think parking brake shows are smaller on 128.
One thing you want to consider if you are going to track that car is upgraded pistons on front calipers. Pistons on those 6 pots are known to crack on track.
If shoes are smaller, there is modification. On E90 forum there is good thread about modifying shoes to fit 324X22mm rotor. Calipers are bolt on.

Yes, the parking brake is the issue. I mentioned the Franken-brake shoes to racer_951 in another thread but couldn't find the thread detailing the mod. A link would be helpful if you know where the thread is located.

[edycol]

Originally Posted by Suprgnat

Yes, the parking brake is the issue. I mentioned the Franken-brake shoes to racer_951 in another thread but couldn't find the thread detailing the mod. A link would be helpful if you know where the thread is located.

Here is quick search.

https://www.e90post.com/forums/showthread.php?t=604481

Search E90 forums and modifications how to fit rear 335 brakes on 328. That is VERY common modification, so there are a lot of posts. 335 or 328 xDrive parking brakes is what you need.

[Suprgnat]

Originally Posted by edycol

Here is quick search.

https://www.e90post.com/forums/showthread.php?t=604481

Search E90 forums and modifications how to fit rear 335 brakes on 328. That is VERY common modification, so there are a lot of posts. 335 or 328 xDrive parking brakes is what you need.

Thanks for that. I forgot the Franken-brake shoe post was on E90post.

[amg6975]

The 335 brakes are far superior to the 135 brakes. You'll need E90 rear hubs but I would honestly sell the 135 front calipers and go 335 all the way around with brass slide pin inserts. The 135 calipers look cool but they're horrible at shedding heat and the ceramic piston caps will eventually fail.

[edycol]

Originally Posted by amg6975

The 335 brakes are far superior to the 135 brakes. You'll need E90 rear hubs but I would honestly sell the 135 front calipers and go 335 all the way around with brass slide pin inserts. The 135 calipers look cool but they're horrible at shedding heat and the ceramic piston caps will eventually fail.

Fixed brake calipers should always be better. But, on E82 front were executed bad. Besides piston issues, they are just too heavy. I would go front from F30 335/340, and rear E82 Brembo or E90 335 sliding calipers.

[Suprgnat]

Originally Posted by edycol

Fixed brake calipers should always be better. But, on E82 front were executed bad. Besides piston issues, they are just too heavy. I would go front from F30 335/340, and rear E82 Brembo or E90 335 sliding calipers.

They're not so bad weight wise if you drop the quick 1.4 pounds per side but yeah, stainless pistons are on the list.

[amg6975]

It's not weight, it's heat dissipation and consumable cost. The 135 blingbros are horrible at getting heat away from the pads/rotors and the pad/rotor choices are limited.

The 335 front brakes have larger, and thicker rotors with significantly more cooling volume inside the rotor itself. Since the 335 and M3 share a pad design as well, everyone and their sister make pads for the 335 set up, and there are many aftermarket rotor options as well.

Edit: found a picture of when I did the swap of a 135 and stock size Stoptech 335 front rotor:

[Suprgnat]

Originally Posted by amg6975

It's not weight, it's heat dissipation and consumable cost. The 135 blingbros are horrible at getting heat away from the pads/rotors and the pad/rotor choices are limited.

The 335 front brakes have larger, and thicker rotors with significantly more cooling volume inside the rotor itself. Since the 335 and M3 share a pad design as well, everyone and their sister make pads for the 335 set up, and there are many aftermarket rotor options as well.

Edit: found a picture of when I did the swap of a 135 and stock size Stoptech 335 front rotor:

I get that. If I ever go from road and track to track and road I'll probably go with a Stoptech BBK. I started a 335i upgrade but they didn't fit under my stock 207Ms, which mattered at the time before I got my current wheels. I did go with directional CSL 345x28s to help a bit with heat on the bling calipers after I got my wheels though.

Sold them for a song with the Bimmerworld brass caliper guides. Didn't loose any money on the parts, but took a bath on my labor:

[edycol]

Originally Posted by amg6975

It's not weight, it's heat dissipation and consumable cost. The 135 blingbros are horrible at getting heat away from the pads/rotors and the pad/rotor choices are limited.

The 335 front brakes have larger, and thicker rotors with significantly more cooling volume inside the rotor itself. Since the 335 and M3 share a pad design as well, everyone and their sister make pads for the 335 set up, and there are many aftermarket rotor options as well.

Edit: found a picture of when I did the swap of a 135 and stock size Stoptech 335 front rotor:

I get that 335 rotor is bigger. But fixed design is better from performance stand point, reliability, equal application of force.
335 front rotors are IMO better choice. But rear are not. Rear have same thickness as 135 although diameter is bigger. But overall pad contact surface on 135 is better due to DSC functions. Fixed design is also better when it comes to electric diff. function etc.
One thing that you have to take into consideration is weight of 335 front rotors. While 135 calipers are heavy, they are not rotating. Rotational weight if 335 rotors is something to take into consideration. It is like having RFT on wheels.
Another problem is that sliding calipers don't apply same force on both sides (common to have outside pad worn out less). On smaller rotors it is nit an issues. But on big rotors it is and are prone to vibration due to different forces on two sides. It is downside of sliding design. F10 had huge issues with that and BMW went ATE 4 piston on cheaper models on G series.
What I will do (E90 328 xDrive, got parts) go front F30 335 Brembo (340X30) and rear E82 Brembo. With that I avoided super heavy Brembo calipers from E82 and E90 328/330 performance package, 2lbs lighter rotors than 335 E90, and in back Brembo calipers from E82/E90.

What I found out on track (and due to cooling modifications, I can stay indefinitely on track, and did sessions as long as 2hrs) is that rear brakes are real issue. Even my regular front rotors (312X24mm) don't have issues. But rear pads get obliterated due to e.diff function (which I don't want to code out due to xDrive function to split torque 20/80%). And rear ones are ones that have heavy discoloration due to heat.

[edycol]

Originally Posted by Suprgnat

I get that. If I ever go from road and track to track and road I'll probably go with a Stoptech BBK. I started a 335i upgrade but they didn't fit under my stock 207Ms, which mattered at the time before I got my current wheels. I did go with directional CSL 345x28s to help a bit with heat on the bling calipers after I got my wheels though.

Sold them for a song with the Bimmerworld brass caliper guides. Didn't loose any money on the parts, but took a bath on my labor:

[IMG]https://lh3.googleusercontent.com/pw...-no?authuser=0[/IMG]

[IMG]https://lh3.googleusercontent.com/pw...-no?authuser=0[/IMG]

You really don't need StopTech BBK. If you want larger rotor, go F30 Brembo from M sport or M performance package, 370x30mm, 4 piston Brembo caliper.
I am soon doing conversion on my E90 328 to F30 335 regular rotors (340X30mm). Caliper on all F30 335/340 packages (except M3) is same and pads have same design (3 different compounds). Here is how calipers look when I just tried them to see whether they fit wheel:

[Suprgnat]

Originally Posted by edycol

You really don't need StopTech BBK. If you want larger rotor, go F30 Brembo from M sport or M performance package, 370x30mm, 4 piston Brembo caliper.
I am soon doing conversion on my E90 328 to F30 335 regular rotors (340X30mm). Caliper on all F30 335/340 packages (except M3) is same and pads have same design (3 different compounds). Here is how calipers look when I just tried them to see whether they fit wheel:

I'm aware of the many options available for braking systems on this platform.

The OP already has the 135i fronts and is asking about what do do with the existing rears, if anything. Reading this and other threads by the OP, at this time it sounds like he wants a true, bolt on upgrade that doesn't require fabrication or affect street functionality. That pretty much leaves the 42mm sliding caliper rears.

My posts regarding the fronts were in response to comments pointing out limitations/deficiencies of the 135i fixed calipers and I offered suggestions to somewhat mitigate those concerns, i.e. weight and heat. I did not get the impression that the OP was looking to replace his already installed 135i calipers any time soon, but perhaps "down the road".

As to the Stoptech BBK, if my car (doubtfully) morfs into a primarily track driven car, I'll get a braking system designed primarily for the track.

[edycol]

Originally Posted by Suprgnat

I'm aware of the many options available for braking systems on this platform.

The OP already has the 135i fronts and is asking about what do do with the existing rears, if anything. Reading this and other threads by the OP, at this time it sounds like he wants a true, bolt on upgrade that doesn't require fabrication or affect street functionality. That pretty much leaves the 42mm sliding caliper rears.

My posts regarding the fronts were in response to comments pointing out limitations/deficiencies of the 135i fixed calipers and I offered suggestions to somewhat mitigate those concerns, i.e. weight and heat. I did not get the impression that the OP was looking to replace his already installed 135i calipers any time soon, but perhaps "down the road".

As to the Stoptech BBK, if my car (doubtfully) morfs into a primarily track driven car, I'll get a braking system designed primarily for the track.

I think if LSD is not in plan, all track driven 128/328 should upgrade from 300X20mm rotor. E.diff eats those pads.
Here is discoloration of my rear rotor after 120mls track:

[Suprgnat]

Originally Posted by edycol

I think if LSD is not in plan, all track driven 128/328 should upgrade from 300X20mm rotor. E.diff eats those pads.
Here is discoloration of my rear rotor after 120mls track:

And I think an LSD should always be in the plan!

[edycol]

Originally Posted by Suprgnat

And I think an LSD should always be in the plan!

True that!

[racer_951]

LSD is getting done along with the solid rear subframe bushings.

Suprgnat, I love your car. Beautiful! I am jealous

[racer_951]

Thanks guys for your recommendations! Very helpful. I bought the 135i from a BMW dealer mechanic. He mentioned he has rebuilt the calipers but didn’t mention what what type of he used for the rebuild. I’ll keep my fingers crossed and hope they hold up. I spent $500 for the 135i setup: rebuilt calipers, like new OEM rotors, and slightly used Hawk pads. I already track tested the fronts. Holding up pretty well except the power reduction “feature” at the end of the last session.

As for the rear, I bought a set of 328i calipers for now. My parking brakes are mostly gone. I went ahead and bought a set DS2500 328i pads and the parking brake kit from FCPEuro. Testing this setup at Sonoma raceway and Laguna Seca next month.

[Ab28]

Originally Posted by racer_951

LSD is getting done along with the solid rear subframe bushings.

What brand of solid bushings did you go with?

[racer_951]

I went with Turner Motorsports’

https://www.ecstuning.com/b-turner-m...et/tdr9080ss3/