The better (and easier) way to bleed Shimano brakes | Syd Fixes Bikes

welcome to the shed i'm sid mackie's on the camera and today we are going to be learning how to do a gravity bleed on shimano bricks [Music] it smells like molasses to me it's definitely some sort of gel i just can't tell but flavor and near oh yep she's gone chocolate chocolate gel for this task you will need shimano hydraulic mineral oil a basic disc brake bleed kit which includes this little cup and stand a hose and a syringe which we are actually not going to use shop towel allen keys adjustable wrench a paint pen brake cleaner you will also need a brake bleed block say that 10 times fast and comment your time in the comments so how do you know if you need to bleed your brakes i actually know the answer to this question um if your brakes are if your brakes are pulling all the way to the bar or need a lot of pumping up before they feel good so that means you have to do this a couple times before you get a good nice pull on it or if after you've been descending for a while your brakes start pulling all the way to the bar or pulling really inconsistently that probably means it's time to bleed your brakes if your brakes are rubbing you probably need to center them so here's a video for that if your brakes are squawking or you don't have great power at the beginning of a descent but it gets better as you descend it probably means you need to re-finish your brake pads and rotors and we have a video about that right up there so if that's your problem pause this video go watch that one if your problem sounds more like what we discussed at the beginning stay here we're going to show you how to bleed a break our friends have officially figured out that we need bikes with problems to film this channel so you might remember this bike from our fourth lower service it is back for a break bleed and because susie's getting free bike maintenance we're gonna roast her for the fact that there's uh like some sort of goo all over the bike we think it might be like gel what does it smell like it smells like molasses to me it's definitely some sort of gel i just can't tell but flavor and near oh yep she's gone chocolate chocolate gel so we talked to a shimano race mechanic about how to bleed brakes properly and this is the method they told us he said that the syringe method usually works but can sometimes cause problems and it's harder so this is what they taught us this is what we use and our brakes work amazing so that's what we're gonna do all right we got the wheel off so we are going to next pull out the pads because you really do not want brake fluid mineral oil on your brake pads i'm gonna install the brake block well you actually can't install the brake block yet you can see the pistons are pushed out there and that's not enough space so sid is going to use a tire lever plastic tire lever right you don't want to stick them well you can use a metal one but you just want to be careful because if you're not careful pushing the pistons out you can actually like crack them slightly i'm scared no you'll be fine you just want to push in the center of the piston so can you explain a little bit how you're pushing the pistons out basically just sort of pulling back as a lever so you're levering it against the caliper do you think i need to push harder if it's not moving then yes you need to push harder i mean it has moved but then it pops right back it will never be totally flush let's see yeah if it'll fit then that will be okay let's find out your issue is not the pistons your issue is the fact that there's not space between the brakes that's why you always have your allen keys ready to go nope nope oh and no what the actual heck how am i missing is it none of these one okay if you have four piston brakes and you're doing this the process is exactly the same except you have to push all four of the pistons in not just two of them there she goes yeah i think i was actually hitting the frame and i didn't realize it right whoops over shot let's try that again gentle gentle and then we need our little screw back and the screw doesn't have to be tight because it's literally just keeping the block from falling out the next thing you're going to do is make sure that the caliper is lower than the lever so caliper is lower than lever but you also want to make sure that all of the hose goes down because we are gravity bleeding it so now you can see the lever is up here and then it goes down it goes into our frame comes back out it goes sort of flat and up a little bit here but i think that's going to be all right so sid is now going to mark where that break is so that we can get it back to the right position and that's what the paint pen is for now when we put it back we'll just line it up with that this is especially important if you're working on someone's bike other than your own the reason sid is moving this lever is so that she can make sure that it is parallel to the ground because you want this bolt right here to be as at the highest point so that everything is below that so this is the little cup that comes with your shimano bleed kit you do want to be pretty generous with how much mineral oil you put in the cup because really the one way you can really go wrong with this task is to run out of oil and basically suck air into your brake line you do not want to do that as sid pulls out the bolt she's going to make sure that the o-ring is on the screw because otherwise you can accidentally end up with two o-rings on here and then it comes off with the cup and then you lose an o-ring and that's bad because the cup has its own o-ring so i'm going to go ahead and screw this cup in carefully try not to get mineral oil everywhere at this point if your brakes aren't super bad you can go ahead and do a lever bleed which if we've shot that video the link will be right up there that's good it doesn't screw on very tight it doesn't screw on very tight apparently we're gonna pop this puppy out yeah and so to pop it out you wanna just no no don't pull straight because then it will go splash everywhere rotate it around in a circle like the whole thing yep keep rotating keep rotating and pulling lightly there we go sid is going to release that bleed valve and basically she just has to unscrew it slightly but first she's going to attach this hose because otherwise you will get brake fluid all over your caliper and you really don't want to do that if you don't have to you're going to want to have something to catch your brake fluid in because it's kind of gross so that's why i had that tape there because you can't do that in the cup at the same time okay right yeah and i have to do this all by myself because we came up with a stupid idea for a youtube channel then you're gonna release that this guy bleed port like between a quarter and a half a turn is it immediately gonna start oozing out on me um a little bit but it shouldn't be too bad yeah good so she loosened it and then she'll unscrew it by hand a little bit oh my god that looks like sludge whoa so now it's gonna start funneling through this is how gross that stuff looks right now sid is up there making sure that she never runs out of fluid because as she mentioned if you let it run out of fluid then you start sucking air into the system and that's the entire point of kind of need to do the whole thing yeah and what we're going to do is watch down here until the fluid coming out stops being black we want it to be pink which is the color it's supposed to be wow guys this is intense i've i've seen some gross brake fluid this has taken it to a whole new level we're getting pretty clean now i can still see some black in there we're gonna let it go a little bit longer because really if you're gonna do this you might as well do it properly obviously we're doing a rear break here with the rear brake you need to be more careful to be watching the amount of fluid you have here because that line takes a lot of fluid when you do the front brake you can pretty it's pretty much just going to be like about a cup of fluid okay that's looking way cleaner you guys can see that it looks nice and pink down here so sid's going to close the bleed port i'm going to move the bag and then you want to hold the hose straight up in the air so that it stops dripping and twist it as you twist the bleed port okay i think that might be tight enough that i can take the hose now wait don't take the hose off this is a trick this is the trick cover the hose with your finger at the top of it okay then pull it off so once again if you pull kind of to the side instead of straight up dump the oil and then you're going to just lock down the bleed port and you want the blade port tight but you don't want to like force it yeah that's good now that your bleed port is closed you have to plunger the top thing so let's go up there and at this point should i pulse the lever yeah at this point just pump the lever a couple of times just in case there are any bubbles pretty good actually well i got like a little baby bubble a little baby bubble okay that just makes sure that there's no bubbles in the lever so then you put the plunger in and then unscrew that guy you should be able to see fluid right around the edge you can see there's like a little bubble of it and then as sid puts that screw in she's gonna hold a towel right next to it so that any excess comes out onto her towel not all over the lever if you have gotten oil all over your lever you are fine to just like spray the lever down that's no not a problem but we did okay yeah he did a good job this is sid's favorite part of the entire process she gets to spray literally everything with brake cleaner first i'm going to take the block out the reason you do this is your brakes will just not be happy if they have mineral oil all over them would say one of the great ironies of brakes is that the stuff that goes inside it to make it go is the absolute worst stuff to get on the rotors or the pads come on let me make sure i'm pointing it at that and not in my eyes whoa wow that smells strong get that all nice and clean clean this is a great time to replace your pads if you need to while you're at it or sand them down if you've been getting some squawking or unpleasant noises again we have a video much more detail on that that's backwards in what way haven't even had a chance the spring has a right and a left and you just want to make sure you don't touch the pads as much as possible especially because your hands probably have some mineral fluid on them probably over there yep i've been putting everything on the shelf this is the part where we shame sid for putting all of the tools on the not tool shelf so that we'll never find them again sorry i'm not sorry won't apologize to nobody then we'll obviously have to re-center our brake once you have your wheel back on you're going to pump up the lever because the pistons need to go back in and what you'll find is sometimes especially if you had worn brake pads in there your lever will feel kind of weird still which means that you just need to do an additional lever bleed i'm actually feeling pretty good all right the last thing we're going to do is we're going to put our levers back where they go and which we have conveniently marked here's how to do a gravity bleed on shimano brakes in one minute remove the brake pads and push the pistons into the caliper remove the caliper from the frame or fork rotate the bike so that the brake line has a downhill path from the lever to the caliper mark the lever position then rotate the lever so that is parallel to the ground remove the bleed screw and attach the funnel with at least one inch of brake fluid then remove the plunger attach the hose and something to catch the oil to the bleed port and open the blade port one quarter turn making sure there was always fluid in the funnel flush the line until the oil that is exiting is clean then close the bleed port pump the lever to make sure there's no air in it then insert the plunger remove the funnel and install the bleed screw clean the lever and caliper and reinstall the pads and wheel pop the lever to reset the pistons and re-center the brake caliper return the lever to its original position you

Channel: Syd Fixes Bikes

Views: 852,117

Keywords: syd fixes bikes, woman mechanic, bike maintenance, bike maintenance how-to, diy bike maintenance, fix your bike, how to fix your bike, welcome to the shed, learn to fix your bike, wrench on bike, diy bike mechanic, learn to be a bike mechanic, work on your own bike, bike repair, bike maintenance tutorial, female mechanic, brake bleed, gravity bleed, gravity bleed brakes, shimano brake bleed, shimano brake fluid change, mtb bleed hydraulic brakes, mtb gravity bleed

Id: o-YvMRJunwo

Length: 12min 36sec (756 seconds)

Published: Wed Oct 28 2020