Hi everyone! A question that I got quite a few times was how to shorten Shimano
brake hoses when installing new brakes so here is how it's done.
This is a set of Deore XT M8000 brakes
but this procedure can be used on any current Shimano brakes.
The few tools needed are a vise grip, you need an X-acto knife with a good blade
you need an 8 mm wrench, a piece of wood, a hammer
and then a couple of pieces that will come with the new brake set.
The yellow blocks are used to clamp on to the brake hose
Then you have the olive and the insert, I will show you how to use them later
These are specific to the type of brake hose you have.
BH90 is the most current one.
The bleeding tool from Shimano is noting more than a funnel
and finally you're gonna need some Shimano hydraulic mineral oil
You can buy this in smaller containers as well
If the brake hose is externally routed on your bike
just go ahead and install the caliper, then run it nicely
using the posts provided all the way up to the handlebar where you
will be ready to start trimming it to the appropriate length.
For a bike like this that has the brake hose internal to the frame I'm gonna have to
trim that hose right now before I can even route it correctly
You will try to create a 90 degree angle here
so try to cut it as straight as you can.
And you just push down on the blade...done.
Having the hose routed through the frame all the way up
still gives me plenty of slack here at the head tube.
The 1 meter long hose of the front brake is plenty
whether you install it moto-style like you see it here
or whether you install your front brake on the left hand side.
The routing of of this hose is very simple you just go through that clip
and then to the inside of the lower leg of the fork.
You don't need the grips here I just pushed them in temporarily
to give me an idea of where I'm gonna want to have the lever.
These are designed for one finger breaking so I usually install them
about half an inch in from the end of the grip.
Just like this.
Next were disconnect this brake hose from the master cylinder
so what I'm going to do is just angle my lever
about 45 degrees up because this is filled with oil and once I disconnect
the hose I don't want that oil to start leaking from it.
What's called the connecting nut is protected by this rubber boot cover
so slide this off
and then
That's the connecting nut, you're gonna need the 8 mm open wrench
This is normal thread so righty tighty lefty loosey.
It was really tight.
and...just undo it.
Just slide this down onto the hose you're gonna need it later.
Pull on the hose
it's gonna come out.
Time to figure out how much hose you need.
Front brake is fairly easy because you have two fixed points
One is here this clip on the fork
the other one is your master cylinder.
This is going to flex as the suspension compresses
however this is the worst case scenario with the fork fully extended
so if you measure it to the shortest length that you want right now you'll be fine.
I usually leave something like this
Is going to be right here under the handlebar.
If you're unsure make sure you measure this a few times.
Needless to say once you cut it is cut
you can't have it back.
This is where I use this piece of wood again
and I usually put it right on top of the stem.
I have my hose marked right here.
Next you're going to grab the olive and just slide it over the hose
The insert goes right in the middle of the hose here
but you have to push it in all the way.
And this is where you're gonna use that yellow block
with the vise grips and the insert is already right there in the middle.
Take the hammer and just pound it.
Once you're done you want it to be flush to the top of the hose.
So nicely lined up right now: insert, olive, connecting bolt and the rubber cover.
Shimano recommends to put a tiny bit of grease right here
on the outside of the olive and the threat of this bolt.
Grab the 8 mm wrench
and as you're pushing on the hose you're gonna start to tighten this up.
Keep pressure on to the hose.
This is 5-6 Nm so it's not a whole lot
Don't go crazy on this one.
Last thing to do just push that rubber cover back on.
For the rear brake I have to measure the hose as well
Also remember if you have any port covers you have to install those first.
So the worst case scenario in this situation would be
With the handlebar twisted something like that.
So make sure you have a little bit of slack at that extreme.
It is not as bad when you're turning to handlebars the other direction
And then trim it and install it just like I showed you for the front brake.
If you're switching hoses at this time, that is from left to right
it's even more important to have your brake levers angled up like this
because at some point you're going to have
both hoses disconnected so you want to
prevent oil from leaking out of those master cylinders as much as you can.
Rest of the procedure it's exactly the same.
For this next step start with the lever kind of parallel to the ground
and that is one of the bleeding ports of your brake system
the second one it's right here on the caliper,
It is the one covered with that little rubber cap.
Enemy of any brake system
is air trapped inside and this is no different.
And if you think about what we've done
we've definitely introduced a little bit of air here
by disconnecting the hoses.
And that air is now trapped in there and it's going to
prevent your brakes from working properly.
With the bike on the stand
remove the wheel and replace the pads with this bleeding spacer or bleeding block.
Just use that same pad pin to hold it in place.
You're most probably gonna have to loosen up
those caliper bolts because the bleeding block feeds in
from the opposite side, there it goes.
You might be tempted not to install the bleeding block
when you're just shortening hoses,
but I would strongly recommend you do.
otherwise you're gonna overfill the system with fluid.
With the lever somewhat horizontal use a 2.5 mm Hex to remove that top bleeding port.
As you take that out make sure you remove that tiny o-ring as well.
Tiny o-ring that you're gonna find here at the bottom of the funnel as well.
The funnel screws in pretty much where you took that screw out.
Just snug.
and stop.
You're going to remove this oil stop as well you don't need it now.
Pour some oil into the funnel maybe about half of it
and start pumping your brake lever.
As you do that you're gonna see air bubbles coming out
If you were a bit afraid and didn't tighten up this connecting bolt enough before
as you start pumping your lever here it's gonna start leaking so
just tighten it up a little bit more.
Next you might want to just take your wrench
or your screwdriver and just do a little bit of this.
You're trying to encourage those little bubbles
to come up to the top where by pumping your lever
you're gonna get all the air out.
Loosen up the lever on the handlebar and
and just go... see, I just angled it a little bit and there was a bit more air coming out
Do the same with the lever angled about 30 degrees the other way.
Use that oil stopper just to plug the bottom of the funnel
and now you can undo it
without having all that oil pouring out.
As you take out the funnel make sure it comes out with that little o-ring
because next you're gonna replace that
top bleed screw that has it's own o-ring.
Tighten it to about 2 Nm so that's not a lot.
Spray a little bit of Isopropyl alcohol and wipe that lever clean.
I have an older video talking about when and how to replace the brake pads.
Repeat the same procedure for your rear brake and go out and make
sure you do a proper break-in of your brake system
especially if it is a brand new one.
A brake system with no air in it will give you that solid feel at the lever
that would never allow the lever to go all the way down to the handlebar.
A full system bleed requires a couple more steps
but 99% of the time if you're just shortening hoses this is all you need
And that is pretty much the end of my video folks.
If you have questions let me know in the comments below
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and like this video
and until next time I will see you on the trails.
Cheers guys,
Cheers!