How To Bleed Shimano Hydraulic Disc Brakes

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In this video we're going to show you how to bleed a Shimano hydraulic disc brake.

In this instance, we're using one of their lower-level group sets,

but the principle remains the same throughout the Shimano range and also for

the majority of other manufacturers. This is one of those jobs which can seem quite

daunting to the majority of people. When you know what you're doing,

it is relatively simple. Why would you want to do it? Well, if you're getting

reduced braking performance, well, the action of the lever here feels quite

spongy, it might well be you've got some air inside the braking hose here,

and that's when you need to bleed the brakes. But of course, the most important

function of your bike is the braking, so if you're not 100% confident in what

you're doing, we would recommend taking it to a professional bike mechanic.

For this job, you'll simply need a set of Allen keys plus the correct Shimano brake

bleeding kit. Before you start, try to make sure that everything is as clean as

possible. Then you need to get the bleed point of the caliper at the lowest point

of the system so that any trapped air moves upwards. Next use your Allen key to

loosen the brake lever and move it upwards 'til it is roughly level.

Undo the small Allen key bolt on top of the lever, making sure that you keep the

little O ring safe. Then screw in your Shimano bleed pump. Just lightly by hand,

making sure that you don't over-tighten it. Going down to the caliper now,

take off the dust cap. At this point, you might want to remove the wheel to make it

easier to access the brake, but there is no need to on our model.