Soft or spongy brake application is normally caused by worn or leaking hydraulic system components and hoses. For example; if you pull your front brake lever and it pulls all the way to the grip, this might indicate hose expansion which swells the hose instead of applying full pressure to the caliper pistons.

You can often measure a difference in hose diameter when applying the brakes. Leaks in the master cylinder or caliper will also allow air to enter the system decreasing brake efficiency.

The only corrective action for a leaking component is to rebuild it with new seals. Worn hoses that are deteriorated and swelling must be replaced before they burst. Braided stainless steel brake hose replacements are offered as a performance upgrade, and will dramatically improve braking efficiency.