17-10-11, 12:16 AM
If you're getting no bubbles out of the bleed nipples then the air could well be in the hoses and the small amount of fluid the lever moves isn't enough to push the bubble down to the callipers. A good way of shifting it is to send it up towards the reservoir, that way gravity helps you rather than hinders.
Carefully squeeze the brake lever with one set of callipers off (and pads out) until the pistons are most of the way out of the cylinders, a bit of wood about 12mm thick and about 30mm wide for them to bump up against is a good way to discourage them from popping out... just keep an eye on them to make sure they extend evenly. Once the pistons are clamping the wood you can stop pumping and gently force the pistons back in, a couple of G-clamps and an old screwdriver as a lever can help. This pushes any bubbles that had found their way into the hose back up where they can escape into the reservoir.
Leave the cap on the top of the reservoir while you're doing this, the whole point of the exercise is to have a brisk flow of fluid to sweep the bubbles along and you don't want a jet of the stuff squirting out over the paintwork!
Repeat for the other side and you should have an air free system again.
Carefully squeeze the brake lever with one set of callipers off (and pads out) until the pistons are most of the way out of the cylinders, a bit of wood about 12mm thick and about 30mm wide for them to bump up against is a good way to discourage them from popping out... just keep an eye on them to make sure they extend evenly. Once the pistons are clamping the wood you can stop pumping and gently force the pistons back in, a couple of G-clamps and an old screwdriver as a lever can help. This pushes any bubbles that had found their way into the hose back up where they can escape into the reservoir.
Leave the cap on the top of the reservoir while you're doing this, the whole point of the exercise is to have a brisk flow of fluid to sweep the bubbles along and you don't want a jet of the stuff squirting out over the paintwork!
Repeat for the other side and you should have an air free system again.