Tourney3p0

I decided that today would be a good day to try out my one man brake bleeders on my 88 (so all my friends and I could work on the Vette at the same time :lol: ) and I noticed that my front brake reservoir bubbles a little bit when I push the brake. It's not like it causes bubbles to set on top of the brake fluid; the surface stays smooth the whole time. But you can definitely tell something is coming up and disturbing the surface.

The rear reservoir doesn't do this. I assumed it wasn't normal and hoped it might stop after I was finished, but it's still doing it.

I checked the vacuum lines on the brake booster and inspected the master cylinder for any leakage and came up empty handed. I also inspected the brake line as best as I could and didn't find any evidence of a leak.

My brakes aren't spongy or overly hard, but my old second gen Firebird feels a lot better when stopping.

So is this normal? And if not, where would be a good place to start looking?