Tips for Easy Brake Bleeding
Here's my method that I've worked up over the years. It's 100%
guaranteed to get all the air out of your brake system. It's based
on the fact that air in the brake system doesn't want to go down.
It wants to go up, so that's what you should encourage it to do.
Step 1. Use the plastic handle of a screwdriver and tap on the caliper all over it. Do the same on the brake line and all fittings, starting at the bottom and working your way to the top. This will dislodge any air bubbles that are stuck to the walls of the caliper or hose.
Step 2. Tilt the motorcycle and handlebars so that the master cylinder's bore is angled down to the left (viewed as you sit on the bike) The idea here is that the piston end of the master cylinder should be the highest point.
Step 3. Twitch the brake lever. Don't squeeze it, just give it the slightest movement. You should see air bubbles come up through one of the two holes in the bottom of the reservoir. Release the lever and repeat the twitch. Keep doing this until you get no more bubbles. You have now gotten all the air bubbles out of the master cylinder.
Step 4. Bleed the caliper just a touch more to get rid of any remaining bubbles down there.
Step 5. Bleed each banjo fitting. To do this, slightly loosen the fitting while squeezing the lever. Once some fluid leaks out of the fitting, tighten it. Then release the lever. This will get rid of any trapped air in these fittings. Do the bottom ones first and work your way up. Before you do each fitting, tap the hoses below it with the screwdriver again to keep those air bubbles moving up and out of the system.
Step 6. After you've bled the last banjo fitting, do the lever twitch trick again. You may clear a few more small bubbles out of the master cylinder.
At this point, your brakes should be very firm and functional. If they're not, then something else is wrong.
Also, if you ever replace a master cylinder, you can avoid all the bleeding by keeping the brake hose held vertical, and using the lever twitch and banjo bleed methods to just bleed the top end of the brake system once it's all back together. It's a real timesaver since it lets you bleed your brakes with minimal tools.
Step 1. Use the plastic handle of a screwdriver and tap on the caliper all over it. Do the same on the brake line and all fittings, starting at the bottom and working your way to the top. This will dislodge any air bubbles that are stuck to the walls of the caliper or hose.
Step 2. Tilt the motorcycle and handlebars so that the master cylinder's bore is angled down to the left (viewed as you sit on the bike) The idea here is that the piston end of the master cylinder should be the highest point.
Step 3. Twitch the brake lever. Don't squeeze it, just give it the slightest movement. You should see air bubbles come up through one of the two holes in the bottom of the reservoir. Release the lever and repeat the twitch. Keep doing this until you get no more bubbles. You have now gotten all the air bubbles out of the master cylinder.
Step 4. Bleed the caliper just a touch more to get rid of any remaining bubbles down there.
Step 5. Bleed each banjo fitting. To do this, slightly loosen the fitting while squeezing the lever. Once some fluid leaks out of the fitting, tighten it. Then release the lever. This will get rid of any trapped air in these fittings. Do the bottom ones first and work your way up. Before you do each fitting, tap the hoses below it with the screwdriver again to keep those air bubbles moving up and out of the system.
Step 6. After you've bled the last banjo fitting, do the lever twitch trick again. You may clear a few more small bubbles out of the master cylinder.
At this point, your brakes should be very firm and functional. If they're not, then something else is wrong.
Also, if you ever replace a master cylinder, you can avoid all the bleeding by keeping the brake hose held vertical, and using the lever twitch and banjo bleed methods to just bleed the top end of the brake system once it's all back together. It's a real timesaver since it lets you bleed your brakes with minimal tools.
Fred
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