- Coming up, we are going to show you
how to swap over your front and rear brakes
on Shimano hydraulic disc brakes.
So for example, you might have bought a second hand bike
or a new one that's just come with
the brakes the wrong way around for you personally.
Now I've got some good news, and that is if you've
got these junctions on the outer cables just here,
then it's actually an easier and a quicker job
than on standard rim brake cabled bikes.
If you don't have these and the cable simply runs
all the way from the brake lever down to the calliper itself,
it is a much lengthier and more in depth job
and something for another video.
Right, let's go through the tools
that you're going to need for the job.
It might be that you don't need too many at all.
You're going to need a couple of open ended spanners
or wrenches, in this particular bike
it's two eight millimetre sizes that you're going to need
and that might differ slightly for your own personal bike
you're gonna have to see in a few moments time.
I'm also going to need to be able
to take the front wheel out and I'm going to need
a six millimetre Allen key for that,
and also a travel spacer like this for the disc brake pads.
If things don't go to plan, and I'll explain that
a little bit later in the video,
there could be some more tools that you need.
Firstly, a very small flat headed screwdriver,
a two and a half millimetre Allen key,
a bleeding block, a plastic block which looks like this,
some disc brake hydraulic mineral oil,
a hydraulic funnel which you put in the top,
possibly a magnet,
some rag and some alcohol based
cleaning fluid, I'm having to borrow some from GMBN.
And finally, an old piece of rag, a bit like this.
Before we get on with the job proper,
I'm going to remove the front wheel
which is what I need my six millimetre allen key for.
That's just in case any of the hydraulic
brake fluid drips out, we don't want
to get it onto the disc rotor itself.
So remove that, put it to one side.
Now during the process, you don't want to be
pulling on the brake levers at all.
If you think that might accidentally happen,
something like this travel spacer would be a good idea
is to slip up inside the calliper.
That will mean if you do accidentally
pull on the brake levers, it won't push
the pistons out which is something
that requires another job to get them back out again.
Then drape an old rag over, this is to stop any drips
going onto the calliper itself.
You gotta drape it over, or as I'm doing, tying it on.
Next up, we are going to slide the rubber covers
to reveal the fixing underneath.
Do it on both of the front and the rear brakes like so.
Then, get your two spanners, as I said,
on this particular bike it's two
eight millimetre open ended spanners.
And then, we're going to undo
very slightly one of the hoses.
And that's it, just a quarter of a turn.
As you see, there's a bit of a jolt when I did that.
And what happens if you remove it completely,
and you do that on the other side with another jolt,
that can lead to losing some of the internal mineral oil.
So do the same on the other side.
Once you've given them both an initial loosen,
you can undo one of them the whole way
and pull the cable out of one and then the other.
You can leave them dangling.
And a very important reminder now,
do not pull your brake levers on at this point.
Then, it's simply a matter of swapping the lines over.
So we now want the front brake
to be operated by the left lever.
Do the same for the rear.
Then it's just a reversal of the process.
Make sure you don't cross thread this screw
as it goes back in, just do them by hand to start with.
Once you've got them tight before you
put those rubber covers back over,
just give it all a quick clean with some rag
and that alcohol based cleaner,
'cause there has been very small amounts of fluid got out,
not enough to affect the braking or the system.
Just make sure it's all clean,
then slide these rubber covers back on.
Once you've done that, the job is probably done
if you've been pretty careful about this and not lost
much fluid, so take the rag off from around the calliper,
take the travel spacer out if you've used one,
replace the front wheel,
and time to see if they feel alright.
And the answer is, front brake is now on the left
and working very smoothly, rear brake not so smooth.
I'd love to say that I did that deliberately
for the purposes of the next part of this video,
but I didn't, I've just got it wrong.
Nevertheless, we'll go through the next steps,
which should hopefully solve this problem.
So for the next step, you want to reveal
what is under the rubber hoods here at the top.
Now these will differ ever so slightly,
but for this particular Shimano model
we're going to need our very small, fine,
flat headed screwdriver to remove this cover.
So I'm gonna take it out with this magnet,
I don't want to lose that, so just put it very carefully
to one side, I'm gonna leave it on the magnet there.
Then, with that screw out, you can remove this plastic cover
which will reveal this two and a half millimetre screw
that we want to take out in a few moment's time.
Before we get around to that though,
we want to take out the rear wheel
'cause that is the brake with the problem.
Now at this point, we are going
to take the brake pads themselves out.
That's when you're gonna need your
flat head screwdriver again.
But firstly, you need to take this very small pin out.
Then, use your flat headed screwdriver
to undo this screw down here.
And then removing that will mean
that you can remove the pads themselves.
You push them down, hold them at the other end.
They they are, put them carefully to one side.
Now is the point at which you want
to insert your bleed block.
Now, you could get a specific Shimano one,
we couldn't find ours so we're using this as a replacement.
Basically the idea is that it's a piece of plastic
that prevents the pistons from coming out
when you pull on the brake lever at the front.
So we can now undo this bolt with our two and a half mil
Allen key, again it's a small one so just be careful.
And then, you can get your bleeding funnel.
Screw that in replacement of the screw itself.
Now it should be firm, but don't
go overboard, this is only plastic.
Then, take the mineral oil, and just put a small amount
in the top, don't need too much.
Then, remove the plug.
Now, to encourage the bubbles in the system in the air
to come up, you can give a few pulls of the brake lever.
Oh, I got some bubbles there, look already.
If that doesn't work, give the cables some taps,
that will encourage the air up as well.
Now this is an internally cabled bike
which means we can't of course access and tap it all,
but we can start down near the rear calliper
and do the stuff up here as well.
And another good idea, we're putting the bike on
a stand for demonstration purposes,
but of course the air tends to travel upwards,
so raising the front of the bike so that the reservoir
is close to the highest point is also a good idea.
Wow, we've made quite a few bubbles actually.
So hopefully that will resolve our issues.
Once you're happy that you got
all the air out of the system,
replace the plunger in the top, unscrew the funnel,
and because we haven't actually used that fluid
in the system, it's perfectly fine
to just tip it back into its container.
I'm just gonna give that a quick wipe with a rag.
Right, then, get your two and a half millimetre bolt
and the appropriate allen key,
and replace the bolt, making sure that
you haven't lost that rubber o-ring.
Then, you can replace the plastic cover
which goes over the top and take that very small screw
which is attached to my magnet,
put that back in and then screw that up tight too.
(light instrumental music)
That feels a lot better.
If you've had the same problem on both sides,
of course you just repeat all those steps
but for the front wheel instead of the rear,
and then you should be all sorted.
And as I said, if you've done things
or if I've done things much more carefully to begin with,
I probably wouldn't have needed to do all those last steps.
Well, I hope that's helped you, if you've had this problem
where you need to swap the brake levers over.
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