How to Shorten and Bleed MTB Disc Brake Hoses | Step-by-Step Guide

Maintaining your mountain bike’s disc brakes is essential for optimal performance and safety. One of the key procedures in brake maintenance is shortening and bleeding the brake hose, especially when you install new components or adjust your setup. In this guide, we’ll take you through the step-by-step process for performing these tasks on a SRAM DOT Fluid-based system.

Why Shorten Your Brake Hose?

The brake hose on your mountain bike may sometimes be too long after installing new brakes or adjusting the cockpit. A shorter brake hose not only offers a neater look but also improves brake performance by reducing slack. It prevents the hose from snagging on trail obstacles or becoming damaged over time.

Tools and Supplies You’ll Need

Before beginning the procedure, make sure you have the following tools:

• SRAM hydraulic hose cutter
• Finish Line DOT 5.1 Brake Fluid (Only use DOT 4 or DOT 5.1 fluid, as using other fluids can damage the system and reduce braking performance)
• Bleed blocks and pad spacers
• Torque wrench
• SRAM Standard DOT Brake Bleed Kit
• New brake pads (if needed). You can find a variety of options here.

Step 1: Prepare Your Bike for Hose Shortening

1. Remove the wheel from the bike according to the manufacturer's instructions.
2. Place a shop towel under the hose connection point to absorb any brake fluid that may drip when the hose is disconnected. Note: Avoid getting DOT brake fluid on brake pads or rotors, as it can diminish brake performance.
3. Secure the bike in a work stand and remove the brake pads and pad-spring from the caliper. If your brake pads are worn or need replacing, consider getting new ones here.

Step 2: Measuring and Cutting the Hose

1. Hold the hose up to the brake lever, ensuring there’s enough length to create a gentle bend. This allows the handlebar to freely turn at least 120 degrees to both sides.
2. Cut the excess hose using the SRAM hydraulic hose cutter. Make sure to allow enough slack for future adjustments.
3. Be sure to repeat the process for both the front and rear brakes.

Step 3: Bleeding the System

After cutting the hose, air will have entered the brake system, which must be bled to ensure proper function.

1. Prepare the Syringes: Fill the syringes with Finish Line DOT 5.1 Brake Fluid. Do not use mineral oil, as it can damage the brake system.
2. Bleed the Caliper: Attach the syringe to the caliper and bleed out the air, ensuring a solid fluid flow. You can use the SRAM Standard DOT Brake Bleed Kit for this procedure.
3. Bleed the Lever: Similarly, bleed the lever by attaching a syringe and pressing it until all air is expelled.
4. Check for Leaks: Ensure all fittings are secure and there’s no leakage around the hose fittings.
5. Final Testing: Once bled, squeeze the brake lever to test firmness and ensure the pistons are moving freely.

Important Safety Tips

• Do not engage the lever while the hose is disconnected, as this will result in fluid loss.
• Recycle used brake fluid in compliance with local regulations—never pour it down the drain or into the ground.
• Clean any brake fluid spills on painted surfaces immediately with water to prevent damage.

Conclusion

Properly shortening and bleeding your MTB disc brake hoses is an important skill for maintaining peak performance on the trails. By following these steps, you'll ensure your brakes stay responsive and reliable. Remember, if you're ever unsure, consult a professional mechanic to perform these procedures for you.

For more detailed information or troubleshooting tips, refer to the official SRAM MTB brake manuals or visit their website. Don’t forget to check out our SRAM Standard DOT Brake Bleed Kit, Finish Line DOT 5.1 Brake Fluid, and grab some new brake pads if your current ones are worn. Alternative Bleed kits