Make sure you use the correct type brake fluid. A common issue especially with DOT5 is after bleeding the lever may not compress to activate the brakes. This is air in the fluid. DOT4 holds air as visible bubbles, while DOT5 holds air in microscopic bubbles. DOT4 holds water in suspension, while water in DOT5 will settle to the lowest part of the system usually in the calipers, which is why it is important to keep DOT5 systems bled. The cure for suspended air in DOT5 when renewing fluid is to squeeze the lever or pedal with the bleed valve closed, slipping your fingers off the lever releasing it rapidly with the master reservoir cap off. Notice if tiny bubbles come up into the reservoir. Also use a syringe with fluid attached to open bleed valve and force fresh fluid up into the system. With this technique you should be able to get some resistant pressure at the lever.
