Hey everyone, welcome!
In today's video I'm going to cover something that many of you ask for and that is how-to bleed Shimano brakes!
We've been long time Shimano brake users and in this video I'm gonna give you my simple and effective method to get it done
sprinkled with the tips and tricks that we learned along the way.
Obviously this is going to apply to any Shimano MTB brake
whether we're talking about the non-series, Deore, SLX, XT, XTR, 2 or 4 piston, this video will cover them all.
So let's get to it!
And first things first, a good question would be - When do I need to do a brake bleed?
And the simple answer is, once your brakes start misbehaving, they don't feel right,
they feel mushy, you can actually pull the lever all the way to the bar,
when your calipers have sticky pistons, you get rubbing on the disc, all those are good reasons for you to take a look at your brakes.
They might need a full brake bleed or some little maintenance
And that's how my video is going to be structured in two parts, first part that takes care of the caliper side of things.
Second part of it taking care of the actual bleed that requires us to touch the levers.
But what tools do we need to get this done?
The kids toothbrush and the baby shampoo, what do I do with these?
Well, that would be part of the cleaning supplies that I usually use.
And I have mixed a few drops of this shampoo in a spray bottle and I use this to clean.
I also use isopropyl alcohol to clean components
You see the baby toothbrush that is very useful, it's essential for this to be as narrow or small as possible.
Right next to it I have another tiny brush, this is actually a straw cleaning brush that you can find at Dollar store, that can be handy as well,
Q-tips and either shop towel paper towel or a rag is good to have around.
For the actual brake bleed you definitely need the Shimano mineral oil or something equivalent to that
and you're going to need that Shimano oil funnel you see the part number here, that looks just like this.
I also use a tiny piece of hose, this says 6x4 on it
a 2.5 and a 3mm HEX/ Allen,
this is a 7mm wrench,
needle nose pliers, tire levers, the plasticky ones, the small size,
the brake bleeding blocks, the yellow ones from Shimano,
you also have a Sharpie a little Ziploc bag and sandpaper, 120 grit.
And with those tools and supplies you can service pretty much any Shimano brake that exist today,
I'll make sure to mention each tool when the time comes.
By the way if you are just interested in replacing or upgrading your caliper
Yes, you can do it, and I have a video talking about compatibility of calipers and levers
I'll make sure to link it up in the corner.
I mentioned that in Part 1 we're gonna take care of the calipers,
so let's remove the wheels of this TREK to get full access to them.
We're going to remove the pads and if you have one of the cheaper Deore that uses a cotter pin,
use the needle nose pliers to straighten it, pull it right out, and you can pull out the brake pads easily.
If you want to reuse these I will make sure that I write with my trusty Sharpie LEFT and RIGHT on them.
More expensive brakes like this XT will have a circlip at the end of the retaining pin
3mm Allen key to remove, in this case we have finned pads and these are already marked Left or Right if you were to reuse them.
At this point many people will just push those pistons back.
But if you look carefully they are absolutely covered in fine brake dust
and pushing the filthy pistons back into the caliper body, believe it or not,
is the number one reason for the so-called sticky pistons that you've probably heard of.
So just use soapy water to soak your caliper,
then use the tiny brush to clean it thoroughly, rinse it at the end with soapy water as well.
You can then use paper towel, just thread that in and at least this caliper should be ready to go!
If you suspect any oil contamination I would use the isopropyl alcohol first
before using the soapy water, definitely use the tiny brush,
Some people prefer to use Q-tips because they have them around the house
and especially if you have a 4-piston caliper, this type of brush might be better than using the toothbrush that you saw.
At this point I would grab the brake lever gently pump it once or twice and keep an eye on the movement of the pistons
you're definitely going to notice the sticky pistons at this time
and if you want to be thorough with your clean, spray, brush and rinse again at this point.
And when there's no issues, like with this caliper, I take my tire lever
trying to aim straight to the middle of that piston I just push it back, push it on one side,
go to the other side and do the same you want to push these back all the way.
If you're not comfortable doing that with the tire lever, yes, you can crack the pistons that way,
there's a safer way of doing it by using an old set of brake pads and a flat screwdriver .
Just push the pads into the caliper. Yes, they are pushed backwards but it doesn't matter,
and then you're going to put the blade of the screwdriver in between the pads
and that way you apply nice, even pressure on the pistons
you are definitely not going to crack them if you use this method.
Some companies like Hope recommend to put a drop of either the oil that they usually use or something like stanchion lube,
Put a drop of this around the piston before you push it back into the caliper.
In my experience with Shimano brakes if you stay on top of this basic maintenance you don't need to do that.
But if you really do have one of those stuck pistons, what I would do,
I will force it out by holding the other one in place with the tire lever,
spray with the soapy water, clean it, push it back in, and repeat that process a couple of times before you put any greasy substances around the pistons.
If you stuck with me for this long congratulations! This is the end of part 1
and this is the maintenance I always recommend everyone to do definitely when you are replacing the brake pads on your brakes.
And talk about replacing brake pads, I have a video I'm going to link it up in the corner
and if you find this video useful remember to like, subscribe and comment it really helps with the YouTube algorithm.
Let's head into part 2 where we're talking about bleeding Shimano brakes using just this little funnel.
This is what's called gravity bleed which is the safest way to bleed your brakes
and is also something that's used by many UCI mechanics on the circuit out there.
And the second tool that's essential to the brake bleed is this: the brake bleed block.
You have the 2-piston and the 4-piston, they're 10mm thick,
one is 31mm wide the other one is 38mm wide,
and if you don't have the original one from Shimano
you can make yourself one out of wood cut down a credit card whatever you might want, you have the dimensions for it.
I actually trimmed the edges of it the original ones have this little tab, I trimmed that down
so I can insert the bleeding block into the caliper from either side.
Normally the bleeding block with tabs can only be inserted from the inside
and if you're having spacers here for bigger rotors you're going to have to loosen up your caliper
something that you might not want to do especially when it's nicely centered.
Last thing here, you're going to secure that bleeding block in place, use the cotter pin or the retaining bolt that you have for your brakes.
Use your Sharpie to mark the position of your lever,
that's because we're going to move it to make it parallel to the ground,
you want the lever to be at the highest point of the brake line,
in this case we're going to be doing the front brake which is the easiest.
Shimano usually uses a 4mm so loosen this up
and rotate to a horizontal position
The whole point here being to have that bleeding port at the highest point relative to your caliper.
Obviously if you were to deal with your rear brake you would have to angle the bike up a lot more
trying to make sure that you have the caliper the brake line going all the way up to your lever which again would be the highest point
And this is where we're about to open the brake system so if you want to protect your skin, put the gloves on,
this is the perfect timing because next we're gonna get messy!
Okay hopefully not too messy because we know what we're doing.
This is a 2.5mm Allen key and obviously it's going to be Lefty Loosey Righty Tighty.
As you remove this bolt you got to be very careful, you're going to have an O-ring seal.
Most of the time time that doesn't come out with it, so right now it came out without the rubber seal.
But if you reach back in there, here we go, it came right out.
Definitely save this, best is to put it back on the bolt.
And that's where your oil funnel is going to attach, you see a third party one, and the original Shimano.
It does have the little o-ring at the end,
put it on and tighten it, just be gentle here.
And the oil funnel is plugged right now, that's the oil stopper just leave it plugged for now we're gonna fill it up with oil.
But before that we want to attach our little hose to the bleeding port of the caliper.
This is an XT but the current SLX, XTR will be very similar.
If you look carefully here at the bottom, that's where the bleeding port is
covered by this rubber cap, remove that one.
In my case I prefer to use the box wrench, that's the 7mm I told you about
and then, here we go, I attach the hose to the end of it, so that's one type of bleeding port.
On cheaper calipers like this Deore you're going to use a 3mm Allen key to actually open up that bleed port
the bleed port that is separate, it's usually covered with a rubber plug like this so look for that, remove it,
and that's where you're gonna attach the hose.
And I ended up with a super scientific bag, hose, paper clip, 7mm box wrench, all this attached to my caliper
and then up here I'm ready to fill this up with mineral oil,
I usually fill up the funnel about three quarters of the way up because it's never fully perfectly vertical.
That would be good to go, and keep an eye on this so it doesn't go empty at any point.
And now you can remove that stopper
and as I open up that bleeding port you're going to see gravity pushing down the old oil into the bag.
I mean look at this, it's nice and black!
Keep an eye on it, keep an eye on the funnel to make sure you don't run out of oil
and when oil turns pink like you see it here, nice and clean, what you're gonna do is tighten up this bleeding port.
And at this point just move your bars around, tap onto the hose
making sure that if there's any sort of bubbles trapped anywhere, you just give them the option or the opportunity to come out.
At this point you can even try the lever and it should be really nice and stiff.
Remember we're doing this after we closed up the bleeding port on the caliper.
At this point if you ask me, this is absolutely perfect so I'm ready to plug the funnel with this oil stopper just push it right in
At this point you can unscrew it, there shouldn't be any oil spilling out,
remember you have a little o-ring at the bottom make sure it comes out with the funnel.
Grab the 2.5mm Allen with the bolt and the o-ring installed and you're going to seal the master cylinder, here we go.
Come down and disconnect your hose,
Spray a bit of isopropyl alcohol here on the bleeding port and wipe it down,
do the same at the caliper and reattach that rubber cover.
One last step, move your lever to the previously marked position and you're ready to tackle that rear brake.
Wow that was a long video, I hope you guys found it useful.
And I know at least some of you are going to ask me about that sandpaper, what do I do with this?
If after doing all this you install brand new pads that's easy peasy
but if you want to reuse the old ones I would always recommend just to rub them on that piece of sandpaper, circular motion,
spray them with that soapy water and when you put them back they should behave very similar to brand new pads.
So there you have it guys, a complete brake bleed with two parts
Part number 1 where we talked obut all the caliper cleaning and everything else that you should be doing regularly.
Part 2 where we talked about the gravity bleed which is not that complicated
I mean at the end of the day all you do is remove the pads, install the bleeding block, install the funnel,
fill it up with oil, install the hose, open the valve, let all the old oil to come down and you're done with it!
Once you've completed to this procedure your brakes should feel like brand new
and I don't know about you but I try to do this once a year over the winter.
So do you guys have any questions for me?
Do you have any other comments?
Do you have anything to add to what I've described to you today?
Let me know in the comments below, as usual hope you found this useful
Don't forget to like, subscribe, comment, and until next time hope to see you folks on the trails.
Cheers guys, cheers!