no brake pressure

[hadaveha]

Guys let me first say IM sorry for a stupid question, but I have a 1981 gs850g that has sat up for a few years, I romved the calipers, unstuck the pistons, cleaned everything up really well, I drained and replaced the brake fluids, now I am trying to build pressure to bleed the brakes, but I am getting no pressure at al on front or rear. what could I have done wrong

[Rich82GS750TZ]

Assuming you are following the proper procedure form bleeding hydraulic brakes. In the bottom of the the master cylinder reservoir, there are 2 holes, one lager, one smaller. As you pump the lever or pedal to build pressure (or it might be when you open the bleed screw, I don't remember), you should see air bubbles come up through the small hole in the bottom of the reservoir. If not, that tiny hole is probably blocked. Use a very tiny wire (like from a fine brass brush or high-E guitar string to clean out that hole, Hope that helps. I'm sure others will have suggestions as well.

[Rust_to_Redemption]

Could have a bunch of air trapped? Tried using a syringe to "reverse bleed" them yet? Use a syringe and a small length of hose to attach to your bleeder valve, and push brake fluid up the system. Helps get stubborn air out of the system.

[2BRacing]

I have found it helps a lot if you "prime"/bleed the master cylinders properly first, before remounting them and connecting to the brake pipes - it is a messy job, so you do not want brake fluid all over the motorcycle!

Fill the reservoir with fresh brake fluid, hold a finger over the outlet port where the brake line banjo bolt goes into, and operate the lever / rod to build pressure. Release your finger on the outlet just slightly so that fluid can escape (be careful that brake fluid does not spray onto painted surfaces of your motorcycle or car). Hold your finger firmly over the outlet again before releasing the lever / rod to prevent air from getting in.

Repeat this process until each pull of the lever / push on the rod causes a good spray of brake fluid to escape from the outlet. Mount the master cylinders on the motorcycle, and then proceed with bleeding the system via the normal or reverse bleeding method.

[Steve]

Fill the reservoir with fresh brake fluid, hold a finger over the outlet port where the brake line banjo bolt goes into, and operate the lever / rod to build pressure. Release your finger on the outlet just slightly so that fluid can escape (be careful that brake fluid does not spray onto painted surfaces of your motorcycle or car). Hold your finger firmly over the outlet again before releasing the lever / rod to prevent air from getting in.

Repeat this process until each pull of the lever / push on the rod causes a good spray of brake fluid to escape from the outlet. Mount the master cylinders on the motorcycle, and then proceed with bleeding the system via the normal or reverse bleeding method.

I have found it a bit safer (to paint and eyes) if you don't fully block the outlet when you pull the lever for the first few strokes. I uncover the port, pull the lever, cover the port, release the handle until there is fluid flow. After you see fluid, THEN cover the port and pull the lever (gently) to see if you have pressure. When you have pressure, go ahead and put your brake line on and continue bleeding the lines.

I use that same theory to bleed the lines, too. Open the bleeder, pull the lever, close the bleeder, release the lever. Repeat as necessary. It tends to move more fluid down the line quicker than the pump, pump, pump, hold, open bleeder, close bleeder, release lever, repeat method.

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