OK I picked this car up from a guy and have been slowly putting $$ into it. I have not driven many manual vehicles so I am not sure if it is common. My brakes work just fine right after I move out of gear but if I press and depress the brakes multiple times the brake pedal gets tighter and tighter with less and less stopping power. When I go back into gear the brakes act just fine. Is this normal for a manual, is maybe something simple Lillie bleeding the brake lines and refilling brake fluid. Any help would be appreciated

 

https://www.yourmechanic.com/article...er-check-valve

Soemthing wrong with your vacuum system or servo.