95 Blazer 4WD - when I go to depress the brake pedal sometimes it will not go down - if I release a bit and then retry it will brake - the antilock then seems to engage a bit at times

fluid level is fine and I'm pretty sure the pads and linings are ok

Please help - not a safe situation

 

master cylinder?

 

Did you do any hydraulic work? Could the lines need a bleedin'?

 

have not done any hydraulic work - only topped of resevoir with brake fluid

 

bleed the lines