u/Brilliant_Assist_603

Hey everyone, looking for some advice on my 2013 Honda Civic LX.
I think my brake master cylinder might not be working right. When I press the brake pedal, it goes almost all the way down. I have to pump it a few times to get it to stiffen up, but then it slowly goes back down again.

I just picked up the car about 3 weeks ago. The interior is in great condition, the body is straight with no damage, and the paint looks really nice—so I’m hoping this isn’t something too serious.

Has anyone dealt with this before? Could it be the master cylinder, air in the lines, or something else? Trying to figure out if this is something I can fix myself or if I should take it in.

Appreciate any help 🙏