When Do You Need to Bleed Your Brakes?

If you notice any of these symptoms, your hydraulic brakes likely need a bleed:

• Soft or spongy lever — the brake lever pulls all the way to the handlebar with little resistance
• Reduced braking power — you have to squeeze harder than usual to slow down
• Inconsistent feel — the lever feels different each time you squeeze it
• Low fluid level — the reservoir appears less than full when opened

These symptoms typically mean air has entered the brake line, which can happen during shipping or over time with normal use.

What You Will Need

• Mineral oil — specifically formulated for bicycle hydraulic brakes (e.g., Shimano mineral oil or equivalent). Do NOT use DOT brake fluid — it will damage the seals.
• Brake bleed kit — includes syringes, hoses, and fittings. A universal kit works for most e-bike brakes.
• Allen keys (hex wrenches) — typically 2.5mm or 3mm for the bleed port screws
• Clean rags or paper towels
• Gloves — mineral oil is not toxic but can be messy
• Zip ties or rubber bands — to hold the brake lever in position during bleeding

⚠️ Important Safety Notes

• Always use mineral oil — FavoriteBikes hydraulic brakes use mineral oil, NOT DOT fluid. Using the wrong fluid will destroy your brake seals.
• Keep oil away from brake pads and rotors — contaminated pads must be replaced. If oil gets on the rotor, clean it thoroughly with isopropyl alcohol.
• Work in a clean, well-lit area — small air bubbles are hard to see.
• Do not ride until you have confirmed firm brake lever feel — test both brakes before your first ride after bleeding.

Video Tutorial

This step-by-step video walks you through the complete brake bleeding process for hydraulic disc brakes:

Step-by-Step Guide

Step 1: Prepare the Bike

1. Secure the bike in a work stand or lean it against a wall with the handlebar level.
2. Remove the wheel from the side you are bleeding.
3. Insert a brake pad spacer (or folded cardboard) between the brake pads to prevent them from closing.

Step 2: Set Up the Bleed Kit

1. Fill one syringe about two-thirds full with mineral oil.
2. Hold the syringe upright and gently push out any air bubbles.
3. Attach the bleed hose to the syringe.
4. Push oil through the hose until a small amount comes out the other end (no air in the hose).

Step 3: Connect to the Caliper

1. Locate the bleed port on the brake caliper (small screw, usually on top).
2. Remove the bleed port screw with an Allen key.
3. Thread in the syringe fitting and connect the filled syringe.

Step 4: Open the Reservoir at the Lever

1. At the brake lever, remove the reservoir cap or bleed port screw.
2. Attach the second syringe (empty or partially filled) to the lever bleed port.

Step 5: Push Fluid Through

1. Slowly push the mineral oil from the caliper syringe upward toward the lever syringe.
2. You should see air bubbles rising into the lever syringe.
3. Gently tap the brake hose and caliper to dislodge any trapped air bubbles.
4. Repeat pushing fluid back and forth between the syringes 3–5 times until no more bubbles appear.

Step 6: Close and Test

1. With slight pressure on the caliper syringe, close the lever-side bleed port first.
2. Then close the caliper bleed port.
3. Remove the syringes and reinstall the bleed port screws.
4. Squeeze the brake lever several times — it should feel firm and consistent.
5. Wipe any spilled oil with a clean rag.
6. Reinstall the wheel and test the brake before riding.

After the Bleed

• ✅ Lever should feel firm — no more than 1/3 travel before engaging
• ✅ Both brakes should have similar lever feel
• ✅ No oil leaks at the bleed ports or hose fittings
• ✅ Brake pads and rotors are clean and dry

Still Need Help?

If you are not comfortable performing a brake bleed yourself, here are your options:

• Contact us — we can ship you a brake bleed kit with mineral oil and walk you through the process over the phone or video call.
• Visit a local bike shop — most shops can bleed hydraulic brakes. Let them know the system uses mineral oil (not DOT fluid).
• Warranty coverage — if your bike arrived with a brake issue, submit a support request and we will cover the repair cost.