Why Do Some Trailers have a Coiled Brake Line

Updated 06/28/2016 | Published 06/27/2016

Question:

Ive noticed some boat trailers have a brake line coil near the port side wheel. Is this to compensate and equalize the distance from the t fitting to each wheel so one brake wont receive pressure first? Just curious.

asked by: Gil

Expert Reply:

The pressure in a brake line is a constant regardless of whether one line is longer or not. Some people will say it is so the lines are equal length for pressure but the brake fluid cannot be compressed so the line length difference doesn't affect anything.

In some cases it is easier to coil lines (in a downward spiral) than it is to have to cut and flare the lines to length.

Also, with hard brake lines some of the components the lines attach to are fixed, like the frame or the actuator. But some are attached to parts that can move, like the brakes on the axle. The coil in the line can compensate for any movement and vibration so the lines and other braking components do not get damaged.

expert reply by: Michael H