The Slave Cylinder and the Master Cylinder control totally different systems. The Slave has to do with the clutch, and the Master has to do with the brakes. They have nothing in common.
underneath the master cylinder for the brakes in the engine bay.
Rebleed the system making sure to watch the level of the fluid in the master cylinder
If the brakes were working before bleeding and now are worse, then is possible all of the air is not out of the system. Check the wheel cylinders and master cylinder for leaks, and re check any parts just replaced. It is possible that the last repair done to the system caused the problem.
Not really an answer, but another question... did you bleed the brakes after you changed them? I remember that is a critical step, NOT to be missed when working on the brakes. Hope this helps.
The brakes will have either:Another problemNeed to be properly bled.The additional component is probably the anti lock brake servo. This component requires a special bleeding procedure.
Bleed em again. Then replace the brake lines. Which would involve more bleeding.
if all lines are clear,try bleeding master cylinder directly,or you may have a collapsed brake hose on side that will not bleed also check routing of pipes for any kinks.
Bleed the furthest from the master cylinder 1st then the rest in order of distance from the master cylinder.
You start again -sorry, no option if you want to do it properly.
Bleed the master cylinder.& then rebleed the system.
Bleed the brakes starting at the wheel farthest away from of the master cylinder and work towards the closest.