The 'E' Type Forum

A very strange thing occurs with my completely rebuild brakes. Everything is new. New master, new booster, new lines, new pistons, new 4 pot front upgrade, new bottles, new fluid. After bleeding the lines with a pressure bottle system (1.2 Bar) and parallel using a vacuum suction system on the bleeder end there still seems air in the system. First press is deeper then the second one. After the second push I am trying to hold pressure and it very very slowly keeps dropping. I did not start the car (so maybe no vacuum activation yet)…
Checked all connections and lines but no leaking.
As there was almost 1 liter of brake fluid in the vacuum canister before rebuild I suspect the valve on the vacuum canister could be faulty?
What else can this be? Faulty new part like master cylinder?

Are you sure there’s no air in the system? What fluid are you using?

Hi so if I'm reading this right with your foot on the pedal pushing down , it will slowly sink to the floor ? ......... sounds like your new master cylinder is letting by ,