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Bolt on 4-Piston front MB brakes & 2-Piston rear Evo brakes

102K views 170 replies 47 participants last post by  OldBonus 
#1 · (Edited)
I wanted to share my brake upgrade. None of this information is brand new and can be found on another forum if you want to go threw over 70 pages of info. I wanted to make a one post with all the information needed. I recommend upgrading the front and rears together to keep a balance in the braking system.

FRONT BRAKES:

Calipers: 2 used Mercedes-Benz W220 front calipers
2000-2006 S430/S500
both long and short mounting tabs work

Pads: Any brand for MB W220 front calipers

Bolts: 4 Mercedes-Benz part#1234210271
these bolts fit the thread of the MB calipers
the smaller diameter clears the MK3 mounts

Rotors: 2012 Mercedes-Benz R350 front rotors
these are 13-inch diameter

Washers: 3mm thick worth of washers x 4

Hub rings: 67.1mm to 60.1mm aluminum rings
stay away from the plastic ones

Dust shield: don't cut this! avoid sharp edges and a dangerous situation. the shield can easily be bent backwards with a hammer. if it still rubs the rotor after installation, use a large screwdriver to pry it away from the rotor.

Paint: I hit the caliper with a rotating wire brush drill attachment, then 100 grit sandpaper and brake cleaner. I used orange and black engine paints. I removed the bolts 2 at a time to paint them separately.

Brake fittings: threads match, use new copper washers, I am using a previously installed SS line kit

Wheels: 17-inch+, i have 18-inch

Piston comparison: 1x60mm MK3 piston vs 2x44mm & 2x40mm MB pistons

Installation: remove wheel, loosen brake line fitting, remove rear caliper bolts, remove caliper, remove rotor, bend dust cover, install hub ring, install rotor, install loaded caliper using new bolts, 3mm washers goes between the MK3 bracket and the MB caliper, transfer brake line fittings with new copper washers, bleed brakes, install wheel

Total cost: $374. I bought everything on Ebay except the paint.

REAR BRAKES:

Calipers: 2 used 2003-2005 Mitsubishi Evo 8 rear calipers

Pads: Any brand for Evo 8 rear calipers

Bolts: 4 M10-1.5X40mm. $1.06 each at Home Depot.
these bolts fit the thread of the Evo 8 calipers

Rotors: 2005-2007 Suburu WRX STI rear rotors

Washers: 4 2mm thick M10 washers.

Hub: STI hubs are about 58mm. Take the rotor to the machine shop and bore the hubs out to 60.2mm. $64 labor

Dust shield: don't cut this! avoid sharp edges and a dangerous situation. the shield can easily be bent backwards with a hammer. if it still rubs the rotor after installation, use a large screwdriver to pry it away from the rotor.

Paint: I hit the caliper with a rotating wire brush drill attachment, then 100 grit sandpaper and brake cleaner. I used orange engine paint.

Brake fittings: threads do not match. my understanding is that one fitting is flared and the other is inverted flared. They appear to fit at first but I had a leak. I used the stock evo banjo bolts and added a banjo fitting to my brake lines.

Wheels: 17-inch+, i have 18-inch

Piston comparison: 1x38mm MK3 piston vs 2x40mm Evo 8 pistons

Ebrake: no changes or adjustments, works 100%

Installation: remove wheel, loosen brake line fitting, remove rear caliper bolts, remove caliper, remove rotor, bend dust cover, install rotor, transfer brake line fittings, install loaded caliper using new bolts, one 2mm washer goes between the MK3 bracket and the MB caliper, bleed brakes, install wheel

Total cost: $446. I bought everything on Ebay except the paint and bolts. The bolts are from Home Depot.

FRONT PHOTOS:











REAR PHOTOS:











 
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#2 · (Edited)
Awesome pictures! Condensed info is always great.

According to rockauto the stock rear piston is 38mm, so 2x40mm at a bigger radius is well over twice the stopping power.

For the fronts, 1 60mm versus 2 44mm and 2 40mm pistons is over twice the stopping power as well, so it stays pretty balanced.


edit: See post #8, it is not over twice the stopping power. It is an improvement but my math/logic is wrong.
 
#3 ·
Awesome pictures! Condensed info is always great.

According to rockauto the stock rear piston is 38mm, so 2x40mm at a bigger radius is well over twice the stopping power.

For the fronts, 1 60mm versus 2 44mm and 2 40mm pistons is over twice the stopping power as well, so it stays pretty balanced.


Thanks. I'll add the rear piston size.
 
#5 ·
Nice! Thanks for taking the time to put these details together and share!
 
#8 ·
Nice pics! Glad someone put all the information all in one place!

SideWinder: I believe that comparing a single piston caliper to a dual piston caliper will not have double the clamping force unless the pistons are on the same side of the caliper. With a single piston caliper, say a single 1 square inch piston at 100PSI, the piston would be exerting 100LBS of force on the pad between it and the rotor, and the caliper body would be "pulling" with 100LBS of force against the outer pad between the caliper body and the rotor.

In a dual opposing piston caliper, with two 1 square inch pistons, the body of the caliper is fixed, so one piston is applying 100LBS of force to one pad, and the other piston 100LBS of force to the other with the rotor between them.

IF the caliper had two 1 square inch pistons on the same side, then combined they would be applying 200LBS of force to the pad between them and the rotor, and the caliper body would be "pulling" with 200LBS of force against the outside pad and you would have double the clamping force.

The front stock 60mm caliper has an area of 2,826 Square Millimeter. The Mercedes calipers i would assume have a 40mm and a 44MM on the each side so the area of that caliper would be 1256SQmm+1519.76SQmm=2776SQMM (rounded up) or 98.23% of the effective piston area of the stock caliper.

Though add in the mechanical leverage gained from the 1.25" larger diameter rotor and more even contact pressure on the (likely larger) brake pads and im sure it will be an improvement.

The rear comparison would be 1x38mm MK3 piston vs 2x40mm Evo 8 pistons. Stock 38mm piston has 1133.54Sqmm area. Evo has 1256Sqmm or 110.8% of the stock caliper clamping force. Then again add the mechanical leverage of the larger diameter rotor and the likely larger pads and the rears should be a good gain aswell.
 
#9 ·
great write-up. like you I bent my front dust shields away from the larger rotor but I had to trim two small pieces to fit the larger benz caliper.
 
#10 · (Edited)
What diameter are the rear rotors ?

TurboStreetCar, you are 100% right on the clamping force figures.
Having pistons on both sides doesn't double the number of what you would have with the pistons on just one size.
Pistons on both sides just makes things work better, as the pistons can follow the rotor, instead of the whole caliper having to follow, on somewhat undersized pins.
 
#21 ·
Honestly even a 1/2" master cylinder wouldn't go to the floor. You prolly only need to displace about 1-2cc of fluid before its hydro locked. Unless the rotors/pads are crushing under the pressure, or your lines are expanding under pressure there isn't much "flow". It's more just a transfer of pressure. Fluid can be pressurized, but not compressed.

Sidewinder,

As I stated, larger is less clamping force PER POUND of PEDAL PRESSURE.
All a larger master will do is increase speed.
If you have to rely on more pressure on the pedal, that isn't an increase in clamping force when comparing one system to another.

Simple math (hydraulic formula) :
pounds (foot pressure) times area (master cyl bore) = pressure exerted on system.

Nice little on-line program that I use when screwing with brake up-grades:
http://www.tceperformanceproducts.com/bias-calculator/
and
http://www.tceperformanceproducts.com/dual-bias-calc/

Used these, and probably some other to realize that even with 13"/12" front/rear rotors & Z32 calipers, on a 3400 lb car, that there was no way in hell to have good brakes (able to pull 1G) without a power brake booster.
Refference this to the new GT-R, which from the factory can pull close to 1.25G off the showroom floor.

Seem that no matter how much I fabricate/spend, a 25 year old Cressida isn't a super car :(
The cobra brakes on my car once warmed up stop very well. I believe on a heavy car like ours it's more about tire then braking ability. Even 16" rotors with 8 piston calipers on all fours, won't stop a car without enough rubber on the road.

This is why my car will never have a skinny up front.
 
#20 · (Edited)
Sidewinder,

As I stated, larger is less clamping force PER POUND of PEDAL PRESSURE.
All a larger master will do is increase speed.
If you have to rely on more pressure on the pedal, that isn't an increase in clamping force when comparing one system to another.

Simple math (hydraulic formula) :
pounds (foot pressure) times area (master cyl bore) = pressure exerted on system.

Nice little on-line program that I use when screwing with brake up-grades:
http://www.tceperformanceproducts.com/bias-calculator/
and
http://www.tceperformanceproducts.com/dual-bias-calc/

Used these, and probably some other to realize that even with 13"/12" front/rear rotors & Z32 calipers, on a 3400 lb car, that there was no way in hell to have good brakes (able to pull 1G) without a power brake booster.
Refference this to the new GT-R, which from the factory can pull close to 1.25G off the showroom floor.

Seem that no matter how much I fabricate/spend, a 25 year old Cressida isn't a super car :(
 
#22 ·
sixpack: I gotcha there, I thought you were implying you wouldn't get an increase in braking force with a larger master (when you generally would). If you want to increase braking force you could increase master cylinder diameter, or increase brake caliper piston area. Both will ultimately stop you faster.
:lol: @ the super car comment, we're all fighting that one.

Turbo: again I agree, but with a larger master you can build more pressure. When you stand on a cars brakes if you have a bigger master cylinder you'll be able to stop faster (barring you're traction or pad compound limited, like you said).
 
#23 ·
Well that's the thing, you won't build more pressure with a larger master. You'd build more pressure with a smaller piston in the master.

When you push the master with 150lbs of force, and the master has a 1 square inch piston, it will apply 150psi pressure to the braking system.

If you push the master with 150lbs of force, and the master has a .5 square inch piston, it will apply a 300psi pressure to the braking system.

If you push the master with 150lbs of force, and the master has a 2 square inch piston, it would apply a 75psi pressure to the braking system.

You would however, end up with more force with larger Pistons in the calipers.
 
#24 ·
I had looked at ABS's (that is a brand name) electric boosted system, and although the $1000-ish price is hard to take, but possible,
their system size didn't lend it's self to my ITBs any more than the stock system.

Wish someone would come up with a compound master, where a large piston would take up the initial pad advancement,
then a smaller piston would increase the pressure.
This is common on hydraulic hand pumps on things like shop presses, called a Two Stage Pump.
Unfortunately, no one has applied the design to automotive brakes yet.
 
#25 ·
I wasn't looking at it that way, I was looking at it as there's x amount of master cylinder piston travel, with a larger master the brakes will engage sooner and give me more reserve brake pedal travel if my foot can manage. Which isn't entirely correct either haha. Batting 1000!
 
#26 ·
I wanted to get a photo of the front and rear together.



 
#28 ·
Prices are going up on these. I paid $110 shipped and others before me have paid less than $100.
 
#29 ·
yeah i got mine when the thread was first posted on sm for like 76 shipped i think it was. what pads did you go with and how do you like them? i have porterfield rs4 on mine and they stop awesome even when hot but they DUMP dust like crazy. also squeak often at low speeds like when coming to a stop under 10mph. was thinking of getting a set to swap in when not racing....
 
#32 ·
I don't want to take credit for any of that info. 90% of its been posted before on SM. The thread is 30+ pages. The evo rear brake setup is a few years old but the MB setup is from this year.
 
#37 ·
#38 · (Edited)
Well this is the big thing

Link In Previous Post said:
I hope you knew the tires are what's actually stopping your vehicle, not your brakes. More brake torque doesn't necessary mean shorter stopping distance. If you over power the adhesion limit of your tires(lock up, or constant ABS pulse engagement), chances are you are not stopping any faster or with shorter distance.
Moving to bigger brakes isnt so much for having "Stronger" brakes. Its not even really for having more braking force or less pedal effort. Bigger brakes can handle more heat for longer periods of time because the pads/rotors are larger and have more material to dissipate the heat.

A 2 or 4 piston caliper is more desirable then a single piston because it will apply a more even pressure to the pad witch results in more consistent braking over a long period of time.

Single piston calipers concentrate all the force on the center of the pad. This can warp the pad or cause inconsistent contact or pressure across the surface of both the pad and rotor.

The stock brakes can easily lock up the tires at virtually any speed. But take your car up to 100 or so MPH and slow it down in a hurry once or twice with the stock brakes and it should be more then enough to inspire a loss in confidence in the stock rotors.

Brakes convert kinetic energy of the vehicles motion into heat. The heavier and faster the vehicle moves, the more kinetic energy it is carrying.

(Weight X Speed^2)/2 is the formula for kinetic energy.

In order to bring the 3600lb (1633KG) vehicle from 100MPH (44.7Meters/Sec) to 0Mph, 1,631,732 Joules of energy needs to be dissipated. Its dissipated in the form of heat. Joules converts to Watts (heat) using a time period.

The air hitting the front of the car dissipates some, friction in the wheel bearings and drivetrain dissipates some, but the remaining 99% is dissipated by the brake pads and rotors.

The quicker your speed is brought from 100 to 0, the quicker that energy needs to be dissipated resulting in more heat. So if you take a minute to slow down from 100MPH, 1,631,732 joules of energy over 60 seconds is equlvelant to 27,195.5 Watts of heat. If you quickly slow down in 10 seconds, that same energy results in 163,173.2 Watts of heat.

The stock rotors that are thin and small can only handle so much heat before distorting giving the "shimmy" in the steering wheel. Thicker, larger diameter rotors provide more material for the heat to be dissipated by.

I posted a comparison of size between the stock rotors and Cobra rotors in my build thread here. Its a pretty impressive difference.

At least this is the reason i upgraded. The stock brakes actually stopped the car just fine, they just felt like shit doing it.
 
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