Biggest Mistakes Installing Motorcycle Brake Lines (and How to Avoid Them)
Date Posted:30 June 2026
Riders install new brake lines expecting better braking performance, only to end up with a spongy brake lever, fluid leaks, or poor braking because of a few simple mistakes.
Using the Wrong Brake Line
One of the biggest mistakes is buying a brake line that isn't designed for your bike. Even if it looks similar, the length, fittings, or banjo angles may be different.
Most riders assume a brake line is just a hose with fittings on each end, but even small differences can affect how it fits and performs. A brake line that's too short can stretch when the suspension moves, while one that's too long can rub against other components.
Forgetting New Crush Washers
This is one of the most common issues we see. Reusing old copper or aluminium crush washers can lead to brake fluid leaks, even if everything feels tight.
Crush washers are designed to seal when they're compressed. Once they've been used, they often won't seal properly a second time. Installing new washers is an inexpensive step that can save you from leaks and brake problems later.
Not Bleeding the Brakes Properly
Air trapped in the brake system is one of the main reasons riders end up with a soft or spongy brake lever after installing new brake lines.
Bleeding the system takes patience. Even small air bubbles can reduce braking performance. Many riders think they've finished bleeding the brakes when there's still air trapped in the lines.
If your brake lever still feels soft after installation, don't ignore it. Continue bleeding the system until the lever feels firm and consistent.
Routing the Brake Line Incorrectly
Brake lines should follow the factory routing wherever possible.
If the line twists, rubs against the wheel or forks, or becomes tight when the handlebars are turned, it can wear prematurely or become damaged over time.
Before tightening everything down, turn the handlebars fully from lock to lock and compress the suspension if possible. Make sure the brake line moves freely without stretching or rubbing.
How to Check Before Buying Anything
Before ordering new brake lines, it's worth checking a few things first.
- Check your motorcycle's make, model, and year to ensure compatibility.
- Compare the length and fitting angles with your existing brake line.
- Inspect the banjo bolts and fittings for wear or damage.
- Plan to replace the crush washers during installation rather than reusing the old ones.
If you're replacing worn or damaged brake lines, it's also worth checking the condition of your brake pads and brake discs while you're working on the braking system.
The Recommended Fix
The easiest way to avoid installation problems is to use quality brake lines designed specifically for your motorcycle and replace any sealing washers during installation.
Taking a little extra time to route the brake line correctly and bleed the system thoroughly will give you better braking performance, improved reliability, and less chance of having to pull everything apart again.
Bottom Line
If your new brake lines aren't performing properly, it's almost always because of one of these issues:
- The wrong brake line was installed.
- Old crush washers were reused.
- Air is still trapped in the brake system.
- The brake line has been routed incorrectly.
Taking the time to install everything properly helps keep your braking system safe and performing as it should.
Need Help Choosing the Right Brake Lines?
If you're unsure which brake lines fit your motorcycle or need help choosing the right braking components, contact the team at RPM Moto. We're happy to help you find the right parts so you can get back on the road with confidence.