Shorten a hydraulic hose

Skill level 3 of 4 · OverhaulRepairAdvanced40 minHydraulic disc brake

Disc brake moved by fluid instead of cable: more power, self-adjusting as pads wear. The lever piston pushes fluid that moves pistons on both sides of the caliper.

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Tools

Ball-end hex key set (1.5–10 mm): Park Tool HXS-1.2 Professional L-Shaped Hex Set ($$)
Shop rags + nitrile gloves: shop towels and nitrile gloves ($)
Hydraulic hose cutter: Jagwire Sport hydraulic hose cutter ($)
Shimano bleed kit + mineral oil: Shimano bleed kit funnel and Shimano mineral oil ($$)
DOT bleed kit + DOT 5.1 fluid: SRAM DOT Standard Bleed Kit ($$$)

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Steps

Mark the new length with the bars turned fully both ways.
Slide back the hose cover, unscrew the compression nut at the lever and pull the hose out.
Cut the hose square with a hose cutter or very sharp blade (not cable cutters if they crush it).
Fit a new olive and insert, slide the nut on, push the hose fully into the lever and tighten the nut (5–7 Nm).
Bleed the brake, then test hard before riding.

Torque

Fastener	Torque
Hose compression nut	5–7 Nm

Diagram

Cut in half, looking down from aboveDisc brake caliper (either wheel)

Hydraulic disc caliper (section)

Signs it needs doing

Spongy lever
Lever pumps up
Pads drag after a long descent
Fluid leak