I installed a new master cylinder and booster on my dart. Im noticing after I get done driving it that the master is pushing brake fluid out of the cap? I also have a pretty low pedal with good wheel cylinders and calipers as well as no air in the system. Anyone got any ideas what the problem is

new MC is bad. had it happen to me went through everything twice until i figured it out. remans suck.

check to make sure rubber seal is good on MC, did you bench bleed the MC before putting it on, are rear brakes adjusted up. Could also have possible brake hose bad, if not I agree with above statement MC bad

What kind of master is and and where did you get it ?

I just went thru this with a new MC. I suspected that the lid itself was leaking due to sloshing, up and downhills, etc. What I did was to lower the level of the fluid slightly (1/2") and put a bit more bend in the cheesy wire bail for more down pressure on the cap. So far, so good.

Bend the wire down it works

Like they said. Tighten the wire bail. Just squeeze it a little snap it over the cap. Don't take it off the master. Just gently tighten up and replace cap.

Remember he said a low pedal too. On top of the cap not being secured completely check for an internal leak in the master cylinder. Either that or if it has a brake booster make sure the rod isnt too far in or out.

Common failure mode, esp. on rebuilts: Pumps fluid from one reservoir to the other. Scary.

Rick

Had that happen to me also.