Yamaha XVZ 1200 front brake problem

[srednas]

I recently rebuilt the front calipers on both sides of bike replaced pistons, rebuilt the brake master cylinder tried to bleed brakes and still have no pressure build up.ANyone have a suggestion. Bike year is 1983

[bigwater]

You may have inadvertently introduced water into your brake system during the rebuild. It doesn't take much at all to make brakes mushy. Less than a couple of drops. Enough that can be picked up if you leave the parts sitting around on a humid night while you're snuggling in your bed. Brake fluid is a magnet for water, and the more water you get, the less effective your braking power will be.

If you're sure you've got the rebuilds done correctly, you need to completely flush the lines again. Take a coffee can and put about 1/4" of brake fluid in it. Attach a hose to your bleeder zerk, stick the loose end of the hose in the fluid in the can and open the zerk wide open. Pour fresh fluid through the master cylinder and watch it pour out the hose into the can. Pour a whole can through it. Close the zerk around the last 1/8 of the bottle before air gets in, and fill the master cylinder to the optimal level with fresh fluid. Do it quickly, especially on a humid day, but slow enough that the brake fluid doesn't gurgle and pick up air bubbles.

If after that you still have mushy brakes, then your caliper rebuild or your master cylinder rebuild went wrong, and you'll have to start from scratch.

[JakePoppa]

I've done my bike three times and still have crappy pressure. Just need one failure point and it all falls to crap.