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Addicted to oil
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Discussion Starter #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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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.
 

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Addicted to oil
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Discussion Starter #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.
 

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Life is BOOST
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Nice! Thanks for taking the time to put these details together and share!
 

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Sweet! I love your car! I will be the Mercedes brakes on my car soon. I just recieved my calipers and bolts today.
 

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Formerly Nosechunks
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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.
 

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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.
 

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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.
 

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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.
Yup I follow now, you and TurboStreetCar are right. Never thought it through haha.
 

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Darth, no need for a larger master, as there is no appreciable increase in piston area.
A larger master would give you less braking force per pound of foot presssure.
Larger is not always better.
(better known as 'math')
 

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Nice. STICKY!! myth says ebrake cant be kept. Can it?
I kept mine, it was a tight fit but yes you can keep it.

Darth, no need for a larger master, as there is no appreciable increase in piston area.
A larger master would give you less braking force per pound of foot presssure.
Larger is not always better.
(better known as 'math')
I'd disagree there...the larger master would move more fluid for every inch of travel, but at the cost of increased effort per inch. More braking force but more effort.
 

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Formerly Nosechunks
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I'd disagree there...the larger master would move more fluid for every inch of travel, but at the cost of increased effort per inch. More braking force but more effort.
"Less braking force per pound of foot pressure"

Would give the feel of less powerful brakes. a smaller master cylinder would make the brakes feel much stronger.

If i didnt already have my Cobra brake setup i would prolly do the Mercedes brakes.
 

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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 :(
 
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