DIY Brembo GT Big Brake Installation, Part 1
01-05-2009, 06:38 AM
#1
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DIY Brembo GT Big Brake Installation, Part 1
Over the holidays, I had an opportunity to install the complete front and rear set of massive but lightweight Brembo GT big brakes that had been sitting in my garage for a couple of months. This is a fairly long write-up that I had to divide into three parts due to the number of pictures (posts are limited to only 20 pics per), and I’m going to go into some detail about some useful tools to have on-hand to do the work correctly, why bothering with the upgrade at all, the precision rebuild of the two-piece front rotors, and finally only the most unique aspects of the actual installation (since most hardly consider bolting up a set of calipers and installing a set of pads a high degree of difficulty job). This is part one.
I had the extremely good fortune to purchase these used off Craigslist.org from someone who had sold his E55 to a person who wanted original MB brakes instead of these fantastic Brembo brakes. The guy I bought them from had removed them prior to the car’s sale, and was looking to unload them. Lots of places like TireRack sell the Brembo GT big brake kits new; the used kits I purchased are Brembo part numbers 1G1.9022A2 for the front and 2C1.8015A2 for the rear. I would never have purchased these new due to their cost, but I after some negotiations with the seller regarding the cost to replace the front discs and all of the pads, the seller ended up selling the set-up to me for what I considered to be a miracle price even after taking into consideration the cost of the necessary replacement parts. During our negotiations, the seller had informed me that the front rotors had reached the minimum required thickness, so to save me some shipping cost, he removed the worn-out front discs from the hats before shipping. So when the shipment arrived, I received four very dirty calipers (covered with brake dust) with original stainless brake lines (Goodrich supplied to Brembo), two rear 345mm two piece discs assemblies with nearly a full .8mm of wear left (out of 1.0mm total wear allowed), the brackets for each of the calipers, the two front hats, and worn pads that I intended to replace anyway. No installation instructions were included. Once I cleaned up the calipers using a nice bath of Simple Green and water, they looked like this:
The first step in the process of getting these ready to install was to determine exactly what parts I needed to buy, including which pads to use, and to obtain proper torque specifications from Brembo regarding both the bracket to caliper bolts specification and the fasteners holding the discs to the hats specification, and from the MB literature for brake hoses and caliper mounting bolts. Based on my research, I ended up purchasing two new front discs, two front disc hardware installation kits (required for each disc replacement per Brembo), one new front brake line to replace one that got crimped during shipment, a complete set of front and rear brake pads, and a couple of necessary tools. The ready availability of replacement parts for the big brake kits was very comforting.
Tools of Interest
As anyone who works on their own car knows, a new project might mean an opportunity to acquire some useful new tools for the collection or to find someone who might be willing to lend the right tools for the job. My thoughts on using the right tools for this job really came down to the issue of safety. When you’re working with a highly sophisticated electronic braking system such as our cars’ SBC system (which operates under very high hydraulic pressure, combined with ultra-high performance two-piece rotors, all intended to bring our heavy but extremely fast cars down from speed, you realize that when your working on these components that it’s not the time to guess about whether or not you’ve applied the correct amount of torque to the hydraulic line connections, to the fasteners attaching the brake components to the car, or for the fasteners holding the discs to the rotor hats. So that meant acquiring a couple of new torque wrenches to add to my tool chest.
The first one was a Snap-On torque wrench that measures torque in inch-pounds, which is necessary to correctly torque the fasteners holding the bobbins in place on the two-piece rotors. Here’s a picture of the Snap-On torque wrench:
The second torque wrench was a bit harder to find, but is needed to correctly torque the brake hose to the brake line. This specialized Stahlwille torque wrench uses front mounted claw-style flare tools to apply torque on hydraulic line fasteners where it’s impossible to fit any other style of torque wrench and where you really don’t want to guess or accidentally over-tighten the coupling. Here’s a picture of this torque wrench.
Here’s a shot of the 11mm crow’s foot style flare attachment used to torque the hydraulic brake line to the brake hose from the calipers:
Installation and removal of the bolts holding the rear calipers to the suspension knuckles requires a standard torx socket. Here’s a shot of the one I used (and thankfully already had in the toolbox – one less tool to buy):
The Brembo calipers do not mount directly to the car. Instead, you first bolt the separate Brembo caliper brackets to the car using the car’s originally supplied fasteners, reapplied with some Locktite Blue. The calipers then actually bolt to the brackets using a supplied Allen-head bolt that requires a 10mm Allen socket as such:
Another tool I had to locate was a standard 11mm flare wrench. I already owned a metric sized set of flare wrenches, but my set didn’t include an 11mm size. I was able to purchase individually this nice Proto 11mm flare wrench, which is also the correct size for the bleeder screws on the Brembo calipers:
The other tools I wanted to mention as being useful for brake work (and already owned) on our cars are a decent digital brake disc thickness gauge:
The digital gauge is used to measure remaining disc thickness. Since the Brembo set-up eliminates the factory pad wear sensors, you need to periodically physically measure the remaining disc thickness to make sure it’s above the minimum specified thickness of the disc. The next tool is a caliper piston press-back tool:
As anyone who has changed a set of pads knows, you need to press the caliper pistons back into the caliper in order to have enough clearance to install replacement pads.
The next tool was specifically needed to install the larger Brembo rear brake discs on the E55 specifically because the factory dust shield (backing plate) has a shape the would otherwise interfere with fitment if not trimmed off. I used this air cutoff tool:
And although not a tool, the state-of-the-art brake lubricant, CeraTEC, is used to lubricate the pad backing plates and prevent squeal.
Although not pictured, you also need a 4mm or 5mm pin press to remove the pad retaining pins from the calipers.
The value of upgrading
The obvious question, given the cost of the front and rear Brembo kits, is why upgrade at all since the factory supplied brakes do a decent job? There are typically three primary reasons cited: first, the increased braking performance in terms of shortened stopping distances and resistance to heat fade offered by the larger brakes; second, the significant savings in unsprung weight; and third, the “cool appearance” factor. Not surprisingly, the Brembo GTs are clear winners in all categories.
The front brake discs measure 380mm versus 360mm for the stock discs, a 6% increase in disc size. The rear brake discs measure 345mm versus 330mm for the stock discs, a 5% increase in size. The larger swept area of the brake discs allows for increased brake torque and most important, much great ability to dissipate heat. In addition, the Brembo discs, unlike the factory discs, have curved vanes for more efficient venting. Thus, in all but the most extreme track conditions, brake fade becomes a non-issue, and your stopping distances (and margin of safety) have been shortened by the additional brake capacity.
Here’s a shot showing the size difference of the Brembo and stock front discs:
And here’s a shot comparing the Brembo and stock rear discs:
Even more compelling is the weight savings. The stock front calipers weight 16.15 lbs. each, and the stock front discs weigh 33.2 lbs. each. The Brembo front calipers weigh only 10.8 lbs each, and the front larger rotors weigh only 25.2 lbs. each. Thus, in the front of the car, installation of the Brembo GT kit saves unsprung weight of over 15 lbs. at front each corner while increasing the size of the usable swept area of the brakes. The Brembo rear calipers are nearly identical in weight to the factory rear calipers, with the Brembo calipers weighing about a quarter of a pound less. However, the Brembo rear discs weight in at only 14 lbs., which is just over 7 lbs. less than the factory disc. So at the rear of your car, you’ll shave off additional unsprung weight of 7 lbs. at each corner. Overall, the larger Brembo GT brakes/discs reduce the weight of our corpulent cars by over 44 lbs. total. This weight reduction can be really be felt when driving the car with turn-in becoming more responsive with less tendency to plow.
As for the “cool appearance” factor, that was not a factor in my decision to switch to the Brembo GTs, but there’s no doubt that the massive drilled rotors and bright red Brembo calipers look fantastic behind the car’s rims.
I had the extremely good fortune to purchase these used off Craigslist.org from someone who had sold his E55 to a person who wanted original MB brakes instead of these fantastic Brembo brakes. The guy I bought them from had removed them prior to the car’s sale, and was looking to unload them. Lots of places like TireRack sell the Brembo GT big brake kits new; the used kits I purchased are Brembo part numbers 1G1.9022A2 for the front and 2C1.8015A2 for the rear. I would never have purchased these new due to their cost, but I after some negotiations with the seller regarding the cost to replace the front discs and all of the pads, the seller ended up selling the set-up to me for what I considered to be a miracle price even after taking into consideration the cost of the necessary replacement parts. During our negotiations, the seller had informed me that the front rotors had reached the minimum required thickness, so to save me some shipping cost, he removed the worn-out front discs from the hats before shipping. So when the shipment arrived, I received four very dirty calipers (covered with brake dust) with original stainless brake lines (Goodrich supplied to Brembo), two rear 345mm two piece discs assemblies with nearly a full .8mm of wear left (out of 1.0mm total wear allowed), the brackets for each of the calipers, the two front hats, and worn pads that I intended to replace anyway. No installation instructions were included. Once I cleaned up the calipers using a nice bath of Simple Green and water, they looked like this:
The first step in the process of getting these ready to install was to determine exactly what parts I needed to buy, including which pads to use, and to obtain proper torque specifications from Brembo regarding both the bracket to caliper bolts specification and the fasteners holding the discs to the hats specification, and from the MB literature for brake hoses and caliper mounting bolts. Based on my research, I ended up purchasing two new front discs, two front disc hardware installation kits (required for each disc replacement per Brembo), one new front brake line to replace one that got crimped during shipment, a complete set of front and rear brake pads, and a couple of necessary tools. The ready availability of replacement parts for the big brake kits was very comforting.
Tools of Interest
As anyone who works on their own car knows, a new project might mean an opportunity to acquire some useful new tools for the collection or to find someone who might be willing to lend the right tools for the job. My thoughts on using the right tools for this job really came down to the issue of safety. When you’re working with a highly sophisticated electronic braking system such as our cars’ SBC system (which operates under very high hydraulic pressure, combined with ultra-high performance two-piece rotors, all intended to bring our heavy but extremely fast cars down from speed, you realize that when your working on these components that it’s not the time to guess about whether or not you’ve applied the correct amount of torque to the hydraulic line connections, to the fasteners attaching the brake components to the car, or for the fasteners holding the discs to the rotor hats. So that meant acquiring a couple of new torque wrenches to add to my tool chest.
The first one was a Snap-On torque wrench that measures torque in inch-pounds, which is necessary to correctly torque the fasteners holding the bobbins in place on the two-piece rotors. Here’s a picture of the Snap-On torque wrench:
The second torque wrench was a bit harder to find, but is needed to correctly torque the brake hose to the brake line. This specialized Stahlwille torque wrench uses front mounted claw-style flare tools to apply torque on hydraulic line fasteners where it’s impossible to fit any other style of torque wrench and where you really don’t want to guess or accidentally over-tighten the coupling. Here’s a picture of this torque wrench.
Here’s a shot of the 11mm crow’s foot style flare attachment used to torque the hydraulic brake line to the brake hose from the calipers:
Installation and removal of the bolts holding the rear calipers to the suspension knuckles requires a standard torx socket. Here’s a shot of the one I used (and thankfully already had in the toolbox – one less tool to buy):
The Brembo calipers do not mount directly to the car. Instead, you first bolt the separate Brembo caliper brackets to the car using the car’s originally supplied fasteners, reapplied with some Locktite Blue. The calipers then actually bolt to the brackets using a supplied Allen-head bolt that requires a 10mm Allen socket as such:
Another tool I had to locate was a standard 11mm flare wrench. I already owned a metric sized set of flare wrenches, but my set didn’t include an 11mm size. I was able to purchase individually this nice Proto 11mm flare wrench, which is also the correct size for the bleeder screws on the Brembo calipers:
The other tools I wanted to mention as being useful for brake work (and already owned) on our cars are a decent digital brake disc thickness gauge:
The digital gauge is used to measure remaining disc thickness. Since the Brembo set-up eliminates the factory pad wear sensors, you need to periodically physically measure the remaining disc thickness to make sure it’s above the minimum specified thickness of the disc. The next tool is a caliper piston press-back tool:
As anyone who has changed a set of pads knows, you need to press the caliper pistons back into the caliper in order to have enough clearance to install replacement pads.
The next tool was specifically needed to install the larger Brembo rear brake discs on the E55 specifically because the factory dust shield (backing plate) has a shape the would otherwise interfere with fitment if not trimmed off. I used this air cutoff tool:
And although not a tool, the state-of-the-art brake lubricant, CeraTEC, is used to lubricate the pad backing plates and prevent squeal.
Although not pictured, you also need a 4mm or 5mm pin press to remove the pad retaining pins from the calipers.
The value of upgrading
The obvious question, given the cost of the front and rear Brembo kits, is why upgrade at all since the factory supplied brakes do a decent job? There are typically three primary reasons cited: first, the increased braking performance in terms of shortened stopping distances and resistance to heat fade offered by the larger brakes; second, the significant savings in unsprung weight; and third, the “cool appearance” factor. Not surprisingly, the Brembo GTs are clear winners in all categories.
The front brake discs measure 380mm versus 360mm for the stock discs, a 6% increase in disc size. The rear brake discs measure 345mm versus 330mm for the stock discs, a 5% increase in size. The larger swept area of the brake discs allows for increased brake torque and most important, much great ability to dissipate heat. In addition, the Brembo discs, unlike the factory discs, have curved vanes for more efficient venting. Thus, in all but the most extreme track conditions, brake fade becomes a non-issue, and your stopping distances (and margin of safety) have been shortened by the additional brake capacity.
Here’s a shot showing the size difference of the Brembo and stock front discs:
And here’s a shot comparing the Brembo and stock rear discs:
Even more compelling is the weight savings. The stock front calipers weight 16.15 lbs. each, and the stock front discs weigh 33.2 lbs. each. The Brembo front calipers weigh only 10.8 lbs each, and the front larger rotors weigh only 25.2 lbs. each. Thus, in the front of the car, installation of the Brembo GT kit saves unsprung weight of over 15 lbs. at front each corner while increasing the size of the usable swept area of the brakes. The Brembo rear calipers are nearly identical in weight to the factory rear calipers, with the Brembo calipers weighing about a quarter of a pound less. However, the Brembo rear discs weight in at only 14 lbs., which is just over 7 lbs. less than the factory disc. So at the rear of your car, you’ll shave off additional unsprung weight of 7 lbs. at each corner. Overall, the larger Brembo GT brakes/discs reduce the weight of our corpulent cars by over 44 lbs. total. This weight reduction can be really be felt when driving the car with turn-in becoming more responsive with less tendency to plow.
As for the “cool appearance” factor, that was not a factor in my decision to switch to the Brembo GTs, but there’s no doubt that the massive drilled rotors and bright red Brembo calipers look fantastic behind the car’s rims.
Last edited by komp55; 01-05-2009 at 05:31 PM.
01-05-2009, 08:19 PM
#2
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thank you for all info.
a few months ago I looked into this because I wanted replace my stock rotors with full carbo-ceramic ones, keeping original calipers.
your brembo set seems quite the same as the first version performance package: 4+4 pistons ; 380mm rotor.
while it is obvious the weight saving on rotors, as they are semi-floating style, I am a bit surprised reading the big difference you found in caliper weight: is it because of different material?
.. I thought (better, I hoped !) they were quite the same caliper.
also, I thought the new larger brackets could fit our stock caliper (that is nearly identic, 4+4 pistons). can you confirm ?
ps:
as for REAR, I knew that unfortunately stocks don't come with replaceable brackets and maybe 360mm rotors from amg65 should have required the hub replacement.. .
a few months ago I looked into this because I wanted replace my stock rotors with full carbo-ceramic ones, keeping original calipers.
your brembo set seems quite the same as the first version performance package: 4+4 pistons ; 380mm rotor.
while it is obvious the weight saving on rotors, as they are semi-floating style, I am a bit surprised reading the big difference you found in caliper weight: is it because of different material?
.. I thought (better, I hoped !) they were quite the same caliper.
also, I thought the new larger brackets could fit our stock caliper (that is nearly identic, 4+4 pistons). can you confirm ?
ps:
as for REAR, I knew that unfortunately stocks don't come with replaceable brackets and maybe 360mm rotors from amg65 should have required the hub replacement.. .
01-06-2009, 04:03 PM
#3
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Thread Starter
The weight saving in the rotors is due to the lightweight hats used in the Brembo GT set-up. The cast rotors are very heavy. I'm not sure I understand what you're asking about the brackets. The factory calipers do not have separate brackets; the mounting holes are part of the caliper casting. Both the front and rear Brembo GT calipers have detachable mounting brackets; I'm pretty sure using different mounting brackets, along with different hats, is the manner that allows them to limit the number and variety of calipers and discs required to service so many models of cars.
01-06-2009, 06:01 PM
#5
MBWorld Fanatic!
The weight saving in the rotors is due to the lightweight hats used in the Brembo GT set-up. The cast rotors are very heavy. I'm not sure I understand what you're asking about the brackets. The factory calipers do not have separate brackets; the mounting holes are part of the caliper casting. Both the front and rear Brembo GT calipers have detachable mounting brackets; I'm pretty sure using different mounting brackets, along with different hats, is the manner that allows them to limit the number and variety of calipers and discs required to service so many models of cars.
.. seems the twin bro of yours
here is back view: you see the bracket.. I guess it is the same fitting, except yours is bigger to accomodate for your 380mm discs.
Weight should be the same also. don't think yours are aluminium !
sad you don't have the same caliper as me and you cannot confirm this
on the internet there was recently an occasion for new style 6 pistons calipers (it wa sa GT3 fitment but I guess they are the same)
but I prefer my 8-pistons style.
only negative side is that they don't allow enough room for installing 390mm rotors: room left between caliper and rim is 15mm, so I think that I can go max 385mm. should be enough, thou
one day or the other I'll have the rotors carbon made
01-06-2009, 06:12 PM
#6
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No, I can confirm the calipers are different. They mount differently, and they are made from aluminum, not cast iron (hence, the 6 lbs. per caliper weight reduction from stock). As I mentioned, the kit calipers have a detachable mounting bracket, the bracket on the heavy factory calipers is part of the caliper casting.
01-06-2009, 06:32 PM
#7
MBWorld Fanatic!
No, I can confirm the calipers are different. They mount differently, and they are made from aluminum, not cast iron (hence, the 6 lbs. per caliper weight reduction from stock). As I mentioned, the kit calipers have a detachable mounting bracket, the bracket on the heavy factory calipers is part of the caliper casting.
.. sorry, mines are not.
in the pic above you can detect even the part number of the detachable bracket
maybe here it is even more clear
.. I m pretty sure I can replace the bracket with the corresponding part from the p030 package and install 380mm discs
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02-24-2009, 02:18 AM
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Even more compelling is the weight savings. The stock front calipers weight 16.15 lbs. each, and the stock front discs weigh 33.2 lbs. each. The Brembo front calipers weigh only 10.8 lbs each, and the front larger rotors weigh only 25.2 lbs. each. Thus, in the front of the car, installation of the Brembo GT kit saves unsprung weight of over 15 lbs. at front each corner while increasing the size of the usable swept area of the brakes. The Brembo rear calipers are nearly identical in weight to the factory rear calipers, with the Brembo calipers weighing about a quarter of a pound less...
These caliper weight savings (10.8 vs.16.15lbs) are a bit peculiar and since I happen to have both the factory 8 piston calipers and the GT8 calipers I decided to weigh them. The results are as follows:
AMG/Brembo 8 piston caliper 11lbs (no brackets or pads)
Brembo GT8 caliper: 9.3lbs (no brackets or pads)
I believe in the example given for this install the AMG caliper was weighed with pads and the iron mounting bracket installed, while the GT8 caliper had its aluminum bracket installed, but no pads. Also keep in mind the AMG caliper is physically a larger caliper with larger pads (notice the unusually wide annulus on the factory rotors?) The AMG pads would hang of the edges of the 380mm brembo rotor which is why the factory p030 option utilizes 390mm rotors.
PS... An earlier posters asked if the mounting brackets were interchangeable?
Nope! The AMG caliper to mounting bracket hole spacing is approx. 255mm (10") and the GT8 holes are approx. 200mm (7 7/8")
Last edited by havoc01; 02-24-2009 at 11:36 AM.
02-24-2009, 07:01 AM
#14
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Are the AMG calipers you weighed from an E55? I think there is more than one version of the "AMG" 8-piston calipers.
I stand by the weights I measured, and the factory AMG calipers that came off did not have the pads in them when they were weighed. I weighed my parts on a calibrated Mettler-Toledo scale. If I hadn't already sold them, I would be happy to do a re-weigh to confirm my original measurements. Don't know what else say.
It's an interesting point, though, but either way the Brembo GTs are significantly lighter than the AMG calipers they replaced and the effect of the reduced unsprung weight (including the the much lighter rotors is very noticeable in the handling of the car.
I stand by the weights I measured, and the factory AMG calipers that came off did not have the pads in them when they were weighed. I weighed my parts on a calibrated Mettler-Toledo scale. If I hadn't already sold them, I would be happy to do a re-weigh to confirm my original measurements. Don't know what else say.
It's an interesting point, though, but either way the Brembo GTs are significantly lighter than the AMG calipers they replaced and the effect of the reduced unsprung weight (including the the much lighter rotors is very noticeable in the handling of the car.
Last edited by komp55; 02-24-2009 at 07:04 AM.
02-24-2009, 04:48 PM
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Are the AMG calipers you weighed from an E55? I think there is more than one version of the "AMG" 8-piston calipers.
I stand by the weights I measured, and the factory AMG calipers that came off did not have the pads in them when they were weighed. I weighed my parts on a calibrated Mettler-Toledo scale. If I hadn't already sold them, I would be happy to do a re-weigh to confirm my original measurements. Don't know what else say.
It's an interesting point, though, but either way the Brembo GTs are significantly lighter than the AMG calipers they replaced and the effect of the reduced unsprung weight (including the the much lighter rotors is very noticeable in the handling of the car.
I stand by the weights I measured, and the factory AMG calipers that came off did not have the pads in them when they were weighed. I weighed my parts on a calibrated Mettler-Toledo scale. If I hadn't already sold them, I would be happy to do a re-weigh to confirm my original measurements. Don't know what else say.
It's an interesting point, though, but either way the Brembo GTs are significantly lighter than the AMG calipers they replaced and the effect of the reduced unsprung weight (including the the much lighter rotors is very noticeable in the handling of the car.
I don't doubt the weights you measured but based on my own results in which the mounting brackets and pads are eliminated from the equation the difference is only 1.7lbs.
Add the heavy OEM cast iron bracket (2lbs), bolts (.4lbs, brake pads (3.1lbs), and sure enough the entire AMG assembly weighs in at 16.5lbs. As for the GT8 assembly, I don't know what the aluminum bracket weighs but I'll guess 1lb, now throw in the known quantities (bolts/pads) to the caliper weight and we get 13.8lbs.
