If You Machine It, It Will Fit or Yet Another Brake Project

[cdh]

As it can be sometimes challenging to find out what part numbers are for individual Brembo parts, I decided to post some numbers from one of last summer’s projects. And to jot down some comments about the project itself. Now before I put the piece of paper in a place where I’ll know I’ll find it (again), the part numbers used

-Front hats ......... 90.1661
-Front rotors ....... 90.6537 and 90.6536
-Front calipers ..... 20.9733.02 and 20.9733.01
-Front lines ......... 90.3556
-Front pads ......... 07.9551.13
-Front bracket ..... Custom machined T7075 aluminum, Impreglon 222M coated
-Rear hats .......... 90.1685
-Rear rotors ........ 90.6549 and 90.6548
-Rear calipers ...... 20A092.01 and 20A092.02
-Rear lines .......... 90.3559
-Rear pads .......... 07.8645.16
-Rear brackets ..... Custom machined T7075 aluminum, Impreglon 222M coated

Part numbers above give one a front setup of a 6 piston caliper with a 380x34mm cross drilled rotor and a rear setup of a 4 piston caliper with a 380x28mm cross drilled rotor.

Project Itself
First off I must express my thanks to my machinist friend for the various Saturday morning amateur machinist sessions and to a fellow board member for the math work on brake ‘stuff’ and for coming up with the original project that started things. This project is a result of a segue from another project that in itself was a segue from another project. Original project was about putting something Brembo on the back of an e31. With the sale of the other members e31, project scope shifted to seeing what bits could be fitted to an e38. One morning for the S&G factor, put one of the rotor and hat assemblies on the wheel mandrel that was being used to polish up a set up M-Pars that I had. That sort of kicked of this project, how big of a rotor can one stuff in a factory 18 inch M-par rim. As you may deduce from above, a 380mm rotor will fit. Why, because you can…

Since a front and rear hub assembly had been acquired to do fitment and mock ups on, it was not much more effort to have a little scope creep on the e38 project. A number of various brembo related parts had been gathered, so a few combinations were available for mock up. Won’t bore you with all of the mucking about details, but a interesting factoid was found while mocking up the front setup that led to the decision on how the final parts got selected. The rotors and calipers are pretty standard across the various offerings that Brembo has (parts above for front are listed for an Audi), the hats are the particular pieces that garner interest. In doing the front, it was noticed/determined that there a difference between the e39 M5 hat and the e60 M5 hat. The mystery of the e39 hat and it’s authentication is a whole other story. Seems the e60 hat moves the rotor centerline inboard a tad more that the e39 hat. Since the goal is to fit things inside of the 18 inch rim, and Brembo calls for a minimum of 3mm clearance, every mm counts. So e60 hat it is. Fast forward a bit over the mulling and various test fits. Brackets (front and rear) are machined up, coated, and set is installed on an e38 in the snowy north eastern states running 19 inch rims. Only caveat, use new parking brake shoes to get parking brake adjusted correctly. Happy, happy, happy. Back in pot hole country, pontification ensues on getting proper fitment for the rear setup in an 18 M-par. Roads here are not the greatest in some places and I was not that comfortable with the 3mm minimum clearance. So some daylight between parts was desired. In doing some spacer stacking it was determined that 10mm would give the clearance require. With a couple of modification, of course. 12mm spacers and corresponding wheel bolts were ordered. Clearance the parts based on the 10mm and the 12mm would give some extra ‘daylight’. Modifications done for rear clearance are as follows. Caliper mounting bolts. Rather than use the stock rounded head caps screws, new cap screws were obtained and the caliper was machined to accept the full cap head. ie. Mounting hole was bored a bit deeper. Additional bolt thread had been compensated for in caliper bracket design, we were thinking ahead here. Caliper mounting bolts now fit flush with the caliper top and cleared rim. Caliper itself. At the 9 and 3 o’clock position of the caliper (when looked at from the front), the leading edge was lightly milled to give uniform clearance against the inner rim barrel step. Bolt and torque things up with the 10mm spaces and clearance exceeds spec. Use 12mm spacers and there is daylight between moving parts. Happy, happy, happy. Front set up cound get away without using spacers but it is tight, as in right on spec. Again due to peace of mind and to keep the aesthetics, 12mm spacers were put on in front as well.

Miscellaneous Stuff
Pads listed retain the brake wear sensor wire. Unlike the stop tech pads which do not. Front dust shield require minor trim to allow caliper bracket to fit. Rear dust shield requires the whole outer lip to be bent back in order to allow rotor clearance as well as trimming to allow caliper bracket mounting. Factory mount points and bolt sizes were retained so stock brakes could be put back on if required in the future. Car does not stop in a shorter distance with the brake change (love that one), but it does with the tire change. Changed from Michelin Pilot Sports to Pilot Super Sports. Bigger contact patch on the ground now.

Hope you enjoyed the little story.

Craig


Colourful parts to follow along with...
From the left
-What started it all...
-Test fit...
-Coated bracket...
-Front, painted, stenciled and installed...
-Rear, primed and installed...

[SEVEN40iL]

That is sexy!



Will you be providing the dimensions to the custom bracket, if someone were to take on this same project?

[cdh]

Will you be providing the dimensions to the custom bracket, if someone were to take on this same project?

That would be brackets. Fronts are side specific and rears are similar. If you are thinking of doing this, let me know.

Craig

[SEVEN40iL]

That would be brackets. Fronts are side specific and rears are similar. If you are thinking of doing this, let me know.

Craig

Sounds good. Will keep you in mind when I am ready to tackle this.

Thanks Craig!

[AquilaBMW]

Impressive man! Simply IMPRESSIVE! I take my hat off to you! ping:

[BlueCrabMafia]

So the big question is, how much would this setup run?

[DvaSevens]

Makes your car seem like it has something big (bigger than that m62) under that hood!

[cdh]

Sounds good. Will keep you in mind when I am ready to tackle this.

Thanks Craig!

Sounds good. Have some odds n sods left over that may help you out.

- - - Updated - - -

So the big question is, how much would this setup run?

Total Cost would depend on how one gathered up the various pieces. Main items would be...
New e60 M5 Brembo kit (all pieces) @$8,400
Used e60 M5 Brembo Kit (all pieces) @4,500 to $6,000
Custom machined and coated brackets and misc. machine work @$1,500 if one offs
New e60 M5 Brembo hats @$1,100 a pair
T7075 bar stock @$100 plus per foot in 2x2 or 2x2.5 stock

Couple of things encountered when doing this project is that sourcing individual Brembo bits is a bit of a PITA as most distributors only sell and stock 'kits'. Brembo also is a bit of a stickler in asking for the serial number of the original part if you ask for a replacement. Not show stoppers, but something to be aware of.

Craig