How to shorten a MTB brake hose?

Beyond the aesthetic operation, adjusting your Road or MTB brake hoses allows good braking efficiency. Behind this simple cut are some manipulations aiming at purging the system of possible air bubbles.

Required tools

Spanners 2.5 and 4 mm / Wrench 8 mm / Cutter / Pliers / Mallet / Hose bit / Shimano mineral fluid / Shimano bleeding funnel (if not available, we will use a syringe without piston).

1/ Dismounting

Remove the rubber nut cover and then, using the 8 mm spanner, loosen the connection nut fully and pull back to remove the assembly.

2/ Cut

Hold the hose in place with the bit and clamp (you can also remove the brake from the bike and place the bit in a vice for comfort). Cut to the desired length.

4/ New Insert

Using the bit and pliers, hold the hose far enough apart so that the pin can be inserted, then tap gently until it is fully inserted.

5/Remounting

While holding the hose to the bottom of the master cylinder, tighten the connecting nut fully. (Some threads should remain visible, as they were originally.)

6/ Lever orientation

To eliminate any air bubbles, turn the lever to the horizontal position.

7/ Bleed screw

Using the 2.5 mm Allen key, loosen and remove the bleed screw and O-ring.

8/ Funnel

Install the purge funnel or, alternatively, a syringe without a plunger to extend the system and allow air to rise freely.

9/ Add oil

If liquid has escaped when opening or cutting, air will be trapped. Pour some liquid into the funnel to purge the system.

10/ Bleed

The MTB Brake is new, it is therefore not necessary to open the system at the caliper. Operate the lever fully to see the air bubbles rise to the surface.

11/ 45° bleeding

Then repeat the operation by tilting the lever 45° upwards and then downwards until the last bubble is removed (tip: tapping along the hose can speed up the process).