Having trouble bleeding master cylinder on 1992 Merc, Topez, is there a check valve,will not comp. drain

Tell us what you did and then we can tell you where you went wrong. l do not understand comp. drain? Is that completely drain? What are you referring to? Nothing is supposed to completely drain you are only removing air! The check valve is on the booster not the master cylinder.

You did not give enough info to really understand what you are doing. Bleeding a master cylinder and ''emptying it'' is a different situation.

Are you ''bleeding'' the master cylinder to get the air out or just trying to empty it? Good luck. Pops

ok if l get the question correct.you probably changed the master cylinder. If this is the case.there is a process called ''bench bleeding'' This is where u clamp the master cylender into a vice.or it can be done on the car.but u disconnect the brake hoses from the master cylinder.then put some adapters on the output of the master cylinder.should come with a new or rebuilt master cylinder. u place the hoses which come with the master cylender.fill the chambers.then if done on the bench use a punch or phillips head screw driver.if done when installed just pump the brake pedal.installed on the car takes 2 people.hold the lines attatched to the output down in the fluid.pump the master cylinder until u see no more bubbles.when this is done.the master cylinder is properly bled.connect the lines & then bleed the wheel cylinders.

Not that hard to do.and when done properly..you will have excellent brakes.

l own a repair shop,and if your installing a new one on it,you need to bench bleed it before you put it on there,it makes it a lot easier to get a good brake pedal to com up on it,im assuming that is what your doing on it,if im correct it will take you longer to bleed the brakes this way but they will eventually get a good pedal,good luck l hope this help,s.