DIY Brembo Rear Master Cylinder

[nitto12ss]

Well like the tile says I just finished installing a Brembo rear master cylinder off of a 2004 Aprilia Tuono. As some of you may know I did the DIY Brembo hidden rear caliper mod last Monday and was not satisfied with the performance gains, so I decided to add a larger master cylinder to really give the Brembo caliper some driving force.

Ok, so like I said I started with a Brembo MC off of a 2004 Aprilia Tuono.

I had to manufacture a plunger for the MC because the Brembo MC has a tapered plunger so you are not able to use the OEM plunger from the Buell. So I went to the heard wear store and bought a bolt the same size as the OEM Buell plunger and got to work.

OEM plunger left, soon to be plunger right

Finished product

Plunger with Buell OEM hard wear installed

I had to taper the plunger to prevent it from contacting the inside of the cylinder due to a pitch difference you encounter when mounting the Brembo master cylinder.

Pitch difference/ deviation between the MC and the lever.

The deviation is caused because the mounts for the Brembo MC are not threaded like the OEM mounts were so you have to affix the MC to the rear set via locking nuts so you are unable to gain proper alignment. This is not really an issue if you taper the plunger like I did because adequate articulation at the piston is gained because of the tapering.

So once you get the plunger figured out it is pretty strait forward, you just install it and then bleed your brakes.

Well here is the finished product.

Ho, and as for performance all I can say is wow!!!
It actually feels like a brake and not like a peace of wood now, and I no longer have to apply massive amounts of force to the rear lever to get it to work.

So if you plan on doing the Brembo hidden rear caliper mod and would like to add performance as well as looks than I recommend incorporating a brembo MC to the mix.

 

[dave_xb12r]

I think you should sell a kit!

 

[nitto12ss]

I think you should sell a kit!

mehhh, nothing was done that would require any real skill so for now I will just tell you how to do it. Besides, you get a more satisfying feeling when you finish if you did it all by yourself. [up]

 

[nitto12ss]

Hey Stevenc150, you should add this to your 120 + helpful threads, thread

 

[onelogue]

Great write up Nitto12ss,

Couldn't you have waited 'til I finished my hidden caliper mod cause now I wanna jump on this project right now. haha

QUESTION!! So with the offset does the plunger rub in the cylinder at all?

 

[nitto12ss]

QUESTION!! So with the offset does the plunger rub in the cylinder at all?

It will if you do not taper the plunger like I did. It actually rubs the cert clip, but this is a custom job so it will require custom parts. Do yourself a favor if you decide to tackle this project and take the rear set off and and attach the new MC to it. Then when you are fabricating the plunger it is easy to install and take back out when testing for fitment. The whole thing took me about 2 and 1/2 hours to do from start to finish and that includes the trip to the hard wear store.

 

[onelogue]

Do yourself a favor if you decide to tackle this project and take the rear set off and and attach the new MC to it.

Good thinking. I'm strongly considering doing this mod!

Price estimate?

 

[nitto12ss]

The total for me was > $40

$34 shipped for the MC and about $5 for the nuts and bolts.

 

[onelogue]

Not bad! I'm looking into it now.

 

[nitto12ss]

Not bad! I'm looking into it now.

If you have not started yet with the rear caliper I would wait and do it all at once. Also be sure to wipe off all brake fluid as soon as possible when it gets on your bike(and it will)as it is a very corrosive material and will eat at your paint/powder coat if left on for extended periods of time.

 

[onelogue]

My fluid resevoir was leaking under my seat and dripped all over my swing are. Ruined my pain terribly!! thiinking about getting a whole new swing arm or trying to powder coat mine to match the rest of the bike.

Yeah I'm still waiting on my ASB bracket. Then I'm might do it all at the same time.

 

[nitto12ss]

Buy the rattle can touch up paint from ASB, it matches perfectly. I used it to fix my swing arm after my low side and you cant even tell it happened now.

 

[onelogue]

REALLY!?!?! Cause my bike looks like **** seriously! I'll pick some of that up too lol

 

[Stevenc150]

Hey Stevenc150, you should add this to your 120 + helpful threads, thread

Paired it with the Hidden Rear Brembo Caliper link.

 

[nitto12ss]

Paired it with the Hidden Rear Brembo Caliper link.

Thanks brotha, I kinda took the time to do the writeup for that reason.

 

[onelogue]

another rep point cause YOU ROCK. [up]

 

[nitto12ss]

Me or Steven, cuz he is cool to, but I think he has enough rep

 

[nitto12ss]

You know its kinda funny that this tread has gotten 16 comments in a few hours and my thread on the Front Master swap has zero comments. Kinda strange considering the front master swap is probably one of the best bang for the buck mods you can do to the bike. Just an observation [confused]

 

[nitto12ss]

I went back to the drawing board on the mounting system after some safety concerns were raised by Point Doc and BrettXb12r. Need less to say they convinced me so with there suggestions carried out I present to you the new and improved mounting system.

So I got a Helicoils kit in metric size M6-1.0 it comes with everything you will need, 1/4 tap, M6 helicoils, and the installation tool.

Luckily the holes on the Brembo MC are 1/4 so all you have to do is tap it and then install the helicoils.

then I used 3 washers per mount to correct the alignment issue between the MC and the lever.

3 washers is about all you can get away with due to the space limitations, but it corrects the alignment problem reasonably well, but 4 washers would have been ideal.

I also affixed a spring to the plunger connecting to a zipty on the MC to keep the plunger in place and prevent it from falling out.

This is a better and safer way to go about mounting the MC as it corrects the alignment issues which could cause binding and lead to an accident, so if you are going to do this mod you should mount the MC in a similar fashion.

 

[xlr8n_xb]

nitto:
When you did this mod did you use the stock buell fluid reservoir? The brembo one that came with my caliper is smaller. Just wondered if it makes a difference. thanks.