this is how to upgrade your master cylinder on a bmw s1000rr
a long time ago i got rid of the nissen stock master cylinder in this 2010 s1k
and i went with an rcs19 which did really well for a long time at the time i also upgraded to
monoblock calipers and new floating rotors now that i'm kind of getting to the limits of the
rcs 19 i'm upgrading to a brembo cnc racing 19 by 20 master cylinder it's not that there's anything
wrong with the rcs 19 it does what is expected of it but now that i'm doing more harder braking on
a track and in the mountains coming into turns i need something that's going to be more consistent
in braking power because i have to trust these 100 the first thing to do is to get a decent rag
tucked in around the parts you're going to be changing because the last thing
you need is brake fluid spilled on your bike your paint or any other finishes
the next thing to do is take a piece of tape however you need to do it somehow mark
where the master cylinder is as far as how far up and down the bar and also where the
split between the two halves of the case goes because you want to be able to put the new one
as close as you can to the exact same place it'll save you screwing around with adjustments later
that's of course assuming that it's similar so you may have to measure this compared to the
original cylinder in this case i'm going brembo to brembo so i expect it'll be very similar so i'm
just going to take a piece of tape here and then i'm going to mark that piece of tape right where
the split is so there's the piece of tape and then that little ink mark lines up with the splits in
the master cylinder the first thing i'm going to do is crack loose the master cylinder bolt
that connects the banjo fitting of the brake line to the master cylinder all right now it's starting
to weep and i don't want it very loose i just want to make sure i get the grunting done while it's
still attached here and now i'll take these two bolts loose on the master cylinder to pull it off
all right now you've got two bolts right here to hold the front part of the clamp to the actual
master cylinder so i'm going to loosen the bottom one first a little bit because it's the last one
you tighten but only a little bit and then go back to the other and go back and forth now you
notice i'm not breaking loose the line that goes from the reservoir to the master cylinder yet
because if i do that all i'm doing is asking for a mess it's better to pull it off and contain it
versus just take it loose and have it spill all over okay now
and pull that bolt out and you'll notice there's a washer
that goes between the bracket and the bracket for the reservoir and that top one now i know
it's going to drip and that's okay but i'm going to slowly get this banjo bolt out
and then the master cylinder will come out with the reservoir
okay we've got a little drip let's get that guy out don't lose that washer there
and now this assembly can come out and looking at your new master cylinder what you want to
see is that you've got a bolt banjo bolt and two crush washers you can reuse the old bolt but do
not reuse the old crush washers those need to be new some kits may come with a double banjo for a
stacked setup if that's how your brakes are set up then go ahead and use that just pay attention and
make sure that you use whatever bolt was in there before whether it's a stacked or just a single
i'm gonna reuse the black bolt that i had in there before so you basically put one crush washer on it
and then you put it up through the banjo fitting and then you put the second crush washer on it
and then you start gently threading that into the bottom of the master cylinder trying to get
things in place right now we're going to take this half of the clamp off now there's one bolt
two bolts now what you'll notice at least for brembos is most of them will have
an arrow or some marking to show where the top is that is important you want to make
sure that it's facing up or the b the top of the logo is up or whatever because that affects
how the interface is between here and the master cylinder put the two halves together
and start the bottom bolt it'll be easier with a wrench a little bit more control of your angles
but it's going to hold its place which is important because the next thing we want to
do is put the top bolt in and to put the top bolt in you need to have that bracket first now to get
the reservoir loose we've got the bracket and that may have to change locations a little bit
but basically it goes in the same place and then what we want to do is get a pair of needle nose
and pinch that fitting to pull the tubing off and put on the new one now obviously if we take
it loose right there we'd have fluid all over the place so what we'll do is pour the fluid out first
and then that way we don't have such a mess when we take this loose this one just takes
a screwdriver in a couple of spots to get that loose pull those screws out pull the cap off
pull the gasket out and then i'm just going to pour this into the little cup so always make sure
that your cup doesn't have holes in it before you put fluids in it now we just want to take a pair
of needle nose and squeeze that little clamp up there we go then we'll take our tubing off
there we go the tubing for the reservoir goes on this fitting right there so we're
going to put this on here easy enough now we just have to get our little clamp back down
the first thing i want to do is make sure that that's going to fit here first
it's a little bit different angle but it should work always trim that tubing if we need to
now when we come down with this
clamp
and get it down and over there we go where it was before
now we just have to attach that in there so we'll take our top screw
put it through there
get the thread started here
and what may be happening
yeah so unfortunately even though the last clamp worked well this one does not
it wouldn't fit on this one so i had to kind of grind the edges around down here
to make it fit that's just some of the fun you get to have working on motorcycles all right
now that we have this fitting again we have the arrow up put that there with the screw in place
and take this aligned now since there's really not a shoulder on this new bolt
i'm going to use a washer underneath there i don't want to use two because i don't want to
affect how many threads are engaged in the master cylinder when i put these two together
all right now that the bracket actually fits on that side of the clamp i'm going to re
the tubing clamp for the reservoir i'm going to move that hose clamp down in place
you got to get it over the fat part
there we go and you can see it kind of extend up where it widens above the clamp you want that
clamp below the fat part of that nozzle now you can see this thing is already kind of not happy
so i'm gonna have to bend this a little bit once i get everything tight
reposition it let's get the master cylinder on correctly first and then i can finish with that
all right so we've got both clamp bolts started i'm going to take the screws
back out of my because i'm gonna need to fill that up at some point here
and until i get it all figured out around that windscreen it might be awkward doing that
the lids off my reservoir and i've got that loose that loose and the bolt down here
so now what i'm going to do is get the clamp and everything correct with how it was before from
lining up that mark on the blue tape you remember from earlier and it says 10 newton meters max
you want the top one tightened first because what you're going to do is bring that
to a close and then you're going to pick up whatever gap and float the difference
on the bottom one so again i'm going to check my tape make sure that gap is set
and now they're both pretty snug so i'm just going to keep tightening the top one the gap is closed
up there that one's getting tighter too so now what i'm going to do is i'm going to pull this in
until i see my 10 newton meters max okay so that's all snug part of is i think that tubing
is a little bit too long now snake some off of that in fact i'm pretty sure i am because that's
you can see already that that thing has just got too much tubing it needs to be sitting down
closer to there let's take this back off again put the little clamp north of where we want her cut
now that we've got a shorter tubing let's go ahead and slip this guy on there and let's get our clamp
back down there now that looks like it's fitting a lot better
i'll make sure we're going to clear fairing and everything eventually but let's just get it
functional right now now for the master cylinder banjo fitting it wants 23 to 26
newton meters and you always want to be sure you're not gonna mess with cabling like
throttle control cables here or anything else of course my numbers are on the bottom
so i'm gonna have to get underneath it to look at it all right 23 to 26.
all right both of these screws that hold the clamp to the mc are tight the bolt that holds
the brake fitting to the master cylinder is tight i don't see any cables that are
clamped or pinched so that's good next thing to do is to start to fill up the reservoir
this is what i've been advised to use for my spirited writing style now before i start
pumping anything i'm going to squeeze this tube make sure it's facing up and just squeeze it
you can see some little bubbles forming up in the reservoir so i'm trying to squeeze the air
out of the tubing and then i'm just going to tap this guy a little bit just to see if there's any
air i can knock up into the reservoir that way and i see a few little bubbles showing up here
anything you can do to remove air earlier in the process like this is going to be helpful
again we're just trying to get any air we can upward if you go right for the gold and start
shoving fluid down in your system you're going to shove whatever errors in that
system down with it so getting the air out will make your bleeding experience faster
now just by doing this tapping and all the air i've gotten out of that line
the lever is already having pressure to it which is great so i think this is a more effective way
to do your initial startup all right so i'm going to squeeze one two three four
five and crack it just enough there's fluid with some it's a little bit of fizz in it
boy it's got good tension already though if you think about the only air really would be
just in the little section of tubing underneath that master cylinder so you want to be careful you
don't want to push all that air down in the system you want to try to scare it back up to the top
try to get some of this t-shirt right up close here so i'm not spilling on the rest
of this stuff if i can avoid it don't let your reservoir run out of fluid or you're going to
be pushing air down in there squeeze it all the way in and make sure to tighten the valve
before you ever start letting that lever out again all right so i've got everything bled
out just up here now i have not done the calipers yet i've tried to keep the air contained up here
the safe thing to do is to go to the calipers next and i'll put the link to the video below
in the description that tells how to bleed your brakes i'm not going to go through that
again because i've got a video that already goes all the way through that including cycling of
your abs pumps with the gs911 tool so what i'm going to do now that this is all put together
i'm going to put a zip tie around the lever and hold it there overnight and then go ride it
and then once it's sort of settled in then i'll go through and do a full break bleed on it properly
like shown in the video in the description below
the only other thing i need to do is see if my previous lever will go in there this is a brembo
lever and that's fine but i'd already spent the money to get these twms that are low drag which is
important for the texas mile so i want to put this over on here put your cap back on the reservoir
once you have the fluid up to a decent level don't forget your gasket under the lid
over tighten them just make sure everything's sealed well don't forget to put your rubber cap
back on the bleeder valve get rid of that blue tape that i put in here to begin with
the last thing you want to do when you get all the assembly done is spray everything down with
some simple green to get all the brake fluid off that you may have inadvertently got on the bike
the reason for that is not only because that stuff is kind of nasty and corrosive
but you also want to see if you end up having any leaks so you want to make sure everything's clean
to start with and then after you go ride it and use a little bit you want to check
down there for that banjo bolt make sure that there's no fluid around there it's not leaking
i swapped my brembo lever that came with the master cylinder for my twm low drag lever i got
my reservoir bracket adjusted properly so it's in a position where it's not hitting the fairing or
the windscreen trying out this new master cylinder as i'm growing in my riding and being able to come
into turns hotter i've got to really be able to trust these brakes and this racing cnc brembo
19 by 20 is just a night and day difference it's got so much more bite good consistent stopping
power good control with the master cylinder lever feels good ramp it up squeeze it in let it off
that's what i need for this kind of riding you've got to be able to trust your machine especially
your brakes so that's how you replace the front brake master cylinder on your bmw s1000rr
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