How To Bleed Any Hydraulic Bike Brake

Most modern mountain bikes feature hydraulic brakes, which have excellent power and consistency. But to keep them that way it's a routine bleed is needed. In this video, Doddy explains everything you need to know about disk brakes, how they work, the things that can affect them, and importantly everything you need to know about bleeding your brakes.

⏰ Time Stamps 👇
00:00 - Intro
00:42 - Brake overview
05:17 - How does air get in?
08:14 - Bleed kits
09:30 - Mineral oil or DOT fluid?
14:37 - Blake bleeding process
17:32 - Bleeding Brakes - Brands
20:14 - Tips & Tricks

Useful Links:

What brakes do you have? Have you ever bled a brake? 🤔💬👇

Watch more on GMBN Tech...

🎵 Music - licensed by Epidemic Sound
Summertime Madness - Matt Large

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[leftverture]

Thanks for convincing me that this is all over my head. I’ll take my bike in to the shop for this process.

[strayedcat]

WOW! It doesn't get any more thorough that this! Outstandingly masterful!

[jimrutherford]

Probably the best video I've seen on subject of brakes, how they work, and bleeding them.

[thephoenixcycle]

I had a supremely stubborn pair of Shimano M9100s the other day. What I finally had to do was inject oil, with great force into the master cylinder to clear out the a-hole bubbles, stuck in the caliper. You can't be friends with these brakes. You got to be forceful right away and show them who the boss is.

[kevinw]

Nice comprehensive review, covered the vast majority of it for sure! I think one good rule of thumb is to avoid bleeding through any process that puts the system under vacuum, which doesn't really fit good bleeding practice but at times may be tempting. The issue is with the hose connections on syringes to the fittings or the syringe itself. These connections can allow tiny air bubbles to get in when under vacuum and then you may introduce very tiny bubbles to your fluid that you may then push back into the system. As a rule I think it's best to never try to suck fluid through by pulling on syringe plungers and that avoids the problem altogether. If you only ever let fluid in passively via gravity or by pressurizing the system I think the odds of accidentally adding air are prrety small (as long as the fluid you start with is completely bubble free).

[dylan-]

Wow I forgot how good Doddy was. Such an in depth look into how brakes work let alone just bleeding them. Makes so much more sense when you understand what's going on below the surface.

[hyperslowgungamer]

Bubble behind the caliper piston shelf: As you bleed, while moving the lever to move the pistons while bleeding a magura Trail system, tap on the caliper with the hard plastic handle of a screw driver while moving lever around while bleed reservoirs are installed.

[piczonman]

The most thorough explanation of the topic! Cheers.👍

[CuzzyWuzzy]

Brilliant episode, very practical. Thanks Doddy 😁.

[thomasnowsun]

Thank you! I don't think I ever came across a video going through all those details. I finally understood the few missing puzzle pieces I needed to elevate my bleeding skills. Fantastic job 👍

[alanhaze]

I've used my battery razor to great effect to vibrate those capillary bubbles out

[PR_Nick]

I'm sure I'm not alone when I say it would be nice if GMBN Tech worked on some lower end, like proper budget stuff too. I'd have been very interested to see your technique on bleeding Clarke brakes. I'm sure there will be many others that can't afford a bike with mid to top end accessories but still love watching these videos.

Keep us all involved please.

[SUBcyclist]

Excellent video, once again. Dodd truly is omniscient - with regard to bike tech!

[Simon.]

This is the best video about brakes that i've ever seen on the internet so far

[ThunderStruckMTB]

Missed the very important step of cleaning the pistons, opening the system at the lever so the fluid has somewhere to go and the diaphragm doesn't tear, and then pressing the pistons back into their bores so the bleed block actually fits between them.

[fibranijevidra]

Fantastic video. I've learned alot. Thank you.

[Richard-ugel]

Thanks for this video. I learned a lot. It was a nice, clear and concise guide to understanding hydraulic brakes.
I'm been trying to sort out my brakes on my electric scooter, and watching this really helped me understand the system. I think I know how to correct the problem now.

[pw]

Don't forget to mark your brake lever positions before moving them! (Been there, done that)

[yengsabio]

I don't do the bleeding myself. My trusted bike mechanics do it for me. But it's great to learn even only bit-by-bit out of this video, Doddy. I find it very informative.

As my practice for maintenance, I have my hydraulic breaks bled annually.

Lots'a love, cheers, & Mabuhay, from tropical Philippines! #RideOn #KeepBiking

[scandinavianairman]

Automotive mechanic here. I use silicone grease to lubricate the pistons, as you would on a car if you have a stuck piston in the caliper.
It works out really well! But my qualified guess would be that silicone grease for car brakes is only compatible with DOT mountainbike breaks. This made a huge difference on my breaks. (Older aviid elixir model)