removing air from hydraulic disc brakes By EliD, on 2/20/2009 9:39:00 PM

Air trapped in the hydraulic of the disc brakes system can cause not enough brake power.
To repair this problem you have to make normally bleeding, by bleeding
You fill new oil from the lower point (Caliper) trough the system, to the highest point (lever blade) and suck the rest, but this is not what I want to show you here.

Here I show you what do also bike mechanics before doing bleeding,
It is working most of the time without special tools and without the bleeding kit.
And so it work:
Air is lighter then the oil and will go always up when you mix them together.
the front brake cable is shorter and position vertical between the Caliper and the brake lever, that mean taking out air from the front brake will be easier and faster then the rear brake, while working on the rear brake you have to hang the bike or fix them with bike stand vertical position.

Note: I made this treatment on Magura Louise bat 2007 and now they work perfect!
About brakes from other company's I don’t know if it work because I don’t know other systems.

Materials:
5 Mm Allen Key
Torx Key (star key) T7
Brake Oil: magura royal blood
Screwdriver with plastic handle
Rag


1

Loosen slightly the clamping screw of the brake lever with a 5 mm Allen Key and turn the brake lever so that the reservoir is positioned horizontal. Slightly tighten the clamp screw in that position.

2

Fix the caliper so that the hose fitting points upwards! It might be necessary that you have to unscrew the caliper with 5 mm and leave him hang on the hose.
After removing the caliper use the transport device (it is also possible to use plastic card) to prevent the brake pads from being pushes out too far by mistake.
Squeeze slightly the lever blade to tighten the transport device. Und fix it with rubber band or cable tie.


3

Unscrew the Torx T7 reservoir cover and remove the cover with the membrane sitting below.
Warning: These screws are really small!, Small dirt in the head of the screw can prevent from the screwdriver to fit properly in the head of the screw and destroy it.


4

Now you need Oil, screwdriver with Plastic handle and patience!

Fill Oil in the reservoir then knock with the screwdriver slightly on the caliper and the hose, start down and go slowly up.



5

Squeeze slowly and release quickly the lever blade, while making this the oil level in the reservoir will go slowly down and air bubble will go out from the oil.
It's very important to keep the reservoir always full of oil.

After some minutes of knocking, squeezing, releasing and oil filling ( it can take like 10 min for every brake) the level blade become more firm, continue until the brake power will be properly and there is no more air bubbles coming out.

Care for a clean working area! No dirt my come into the brake system!


6

The reservoir has to be full to the top before replacing the membrane and the cover. Replace the cover with the membrane wide side first onto the reservoir.
Tighten the cover with the Torx T7 Wide side first.
Tightening torque 0,6 Nm/ 5 in. lbs.
Oil will spill during this procedure, therefore do not forget to place a rag around the brake lever!


7

Caliper mounting:
Mount the caliper back. Don’t Tighten the Caliper screw now. With one hand squeeze the lever blade and keep the pressure and with the other hand Tight now the Screw. Tightening torque: 6 Nm/ 51 in.lbs

Ready!