I guess it will just leak a little fluid

[Rocketman]

Replaced the master cylinder
New Brake Booster installed
New Brakes installed

Master cylinder still leaks a little fluid out the lid. very frustrating

 

[HawkRod]

I had that, and it turned out to be an issue with the lid - replaced the lid and problem went away...

 

[moparjohnny]

There are usually root causes for all problems just got to get down and dirty sometimes to find the cause,requires a little patience also and little help from fbbo.

 

[khryslerkid]

You can remove the rubber from the lid and check for flatness. Set the lid (without rubber) on the cylinder and see if it rocks.

 

[hunt2elk]

I had one do that once too. Replaced the lid and it still leaked. Turned out that the spring clip wasn't putting enough pressure on the lid. I put the spring in a vise to tighten it up a bit and solved the problem.