How To Bleed A Pre 2011 Hydraulic Rim Brake

isitafox · August 23, 2012

Bleeding hydraulic rim brakes

There are two major ways of bleeding maguras/echos - either with a bleed kit, or submersed in water - such as a bath or bucket. If your bleeding with water it is advisable to do it with a mixture of water and antifreeze, this will not only prevent your brakelines from freezing in winter but should also stop your brake from suffering from sticky pistons.

Bleeding hydraulics with a bleed kit.

Tools needed

For this method you will require a bleed kit. These can be purchased from many online stores or local bike shops.

A Magura bleed kit

Method

Loosen the TPA all of the way off.
Move the whole lever up so that it's pointing forwards instead of down. The bleed screw on the lever has to be at the highest point, so the air can escape.
Take the bleed bolt off of the slave cylinder.
Using one of the clear tubes, attach it to the syringe. Attach a barb to the other end of the tube.
Fill the syringe with water, or oil. People tend to prefer water because it gives a better feel to the lever rather than oil which can sometimes feel spongy. It's also free! I find it easiest to fill it with the tube and barb attached already, makes sure you get the most liquid in there.
Screw it into the bleed hole, making sure that the tube is full up with water before you screw it on.
Make sure you always bleed from slaves to lever
Undo the little grub screw on the lever body.
Optional Step Take the other clear tube and attach a barb to it. Screw it into the bleed hole on the lever.
Optional Step Ask someone if they can hold an old butter tub or something under the tube coming from the lever, otherwise you'll get oil all over your rim/rotor. This isn't too important if you're using water, but it's still useful.
Making sure everything is done up tight, slowly pump the syringe until most of the fluid from it is gone.
Now look at the tube coming out of the lever, if it has bubbles in you need to do that again.
If you're going from an oil bleed to a water bleed, you're going to want to flush the system, so take the syringe off the tube, and fill it with water again, then repeat the bleed process.
Once there are no bubbles in the tube coming from the lever, the bleed is done.
Take the pipe off of the lever and put the grub screw back in. Do this up tight. Remember: When you're taking the pipe off of the lever, make sure to leave the syringe on the pipe coming from the slave.
Take the pipe and syringe off the slaves, and replace the bleed bolt.
You should now have a working brake! If you have any problems, make sure you follow the steps carefully, you may have missed something out.

Bleeding rim brakes in a bucket or a bath

Before you start if this is the first water bleed the brake will have it will need to be flushed out to clear all the oil from the system. To do this simply follow the instructions below but do it with warm soapy water a couple of times then once through with just warm water to rinse. Then you can bleed it properly!

Fill the bucket or the bath full of water.
Take the brake off of your bike and put it in the bucket/bath.
Undo both bleed bolts, the one on the lever and the one on the slave. (Underwater)
The method is tricky at first, but once you have the rhythm, it will take a minute at maximum.
Underwater: hold your finger over the hole on the slave cylinder (remember, when you have your finger on the hole, make sure it is tight and sealed against the hole, other wise it will take longer to bleed and may effect performance), press the lever all the way down, then hold your finger over the hole on the lever body, take your finger off the hole on the slave cylinder and release the lever fully, repeat until you no longer see any air coming out.
Do up both of the bleed bolts. (Again, underwater)
Take the brake out and it should be air free.

If your attempting a bath bleed it's worth watching this video

http://vimeo.com/8678605