well now I have gotten myself into a fine mess, all was going well or so I thought, I took off the old pads, pumped the brake to expose the pistons, cleaned them with brake cleaner and a green scotch pad to remove the heavy buildup. I did not see anything that looked damaged, however on both sides i.e right and left calipers, while working the pistons back and forth I had one of the pistons pop out. I was able to re-insert them and continuing to pump the brake to work the pistons in and out holding one side with the old brake pad to expose the pistons on the other side. All seemed ok so I put some caliper grease on the pistons, the pins and a little on the back of the new pads where the pistons make contact with the pads. Now time to bleed the brakes, I purchased a vacuum pump brake bleeder, then drained the reservoir then opened the bleeders and pumped fluid from each caliper till all seemed empty. Next filled the master cylinder and used the pump to try to suck the fluid down through the system from the bleeder.
All I got was small amounts of fluid. Next I tried the old fashion way, I pumped the brake lever and opened the bleeder, again just a trickle. So this time I tried pumping the lever and cracking the banjo bolt, this produced a little more fluid, so I went back to the bleeder. I tried this on the calipers on both sides of the bike never getting much more than a few air bubbles and small amounts of fluid. During all of this the master cylinder did keep losing fluid, but the brake lever never got any level of stiffness. So now I'm wondering what to look for next, the master cylinder, or caliper seals? There seems to be no leakage coming from the pistons or the pad area, but there really is no pressure buildup, Any idea's guys?