Can't find brake fluid leak

[RIDGERACER383]

I'm losing fluid somewhere on my 68 charger and can't find a leak anywhere.It's not leaking into my booster my vacuum line is dry.I have 4 new brake cylinders on it and checked the back of the drums and it's dry.I have new soft lines on the front.Checked all my hard lines the best I could and didn't find any leaks.The chamber closest to the firewall on the master cylinder is the one losing fluid and I believe that's the front brakes.When I filled it up and pumped the brakes with the car off the fluid was milky looking with bubbles and lost fluid.I checked under the car and found no leaks.Am I missing something?I've bled the brakes a bunch of times starting farthest away from the master and so on and still get no brakes.My master cylinder is new too.I'm lost.

[Chargen69]

you usually want to pre bleed the MC before you start pumping the air in there through the lines, right?

[JB400]

Yes, you're supposed to bench bleed your mc before you bolt it on.

[RIDGERACER383]

I didn't bench bleed it but I'm still losing my fluid somewhere.

[Finn]

Have you tried a UV dye?

[RIDGERACER383]

I've heard of it but havnt tried it.

[charger Downunder]

If your losing fluid it has to be going some where, check the new master cylinder for a leak at the plunger at the rear. If you cant find a leak anywhere keep adding fluid and bleeding the system, the fluid is probably replacing air in the system.

[Chargen69]

If your losing fluid it has to be going some where, check the new master cylinder for a leak at the plunger at the rear. If you cant find a leak anywhere keep adding fluid and bleeding the system, the fluid is probably replacing air in the system.

[RIDGERACER383]

I'll do that and see what I can find.I'm going to get it in the air too and double check everything then bleed them and see if I'm getting any air out.

[RIDGERACER383]

Does the 4 way block that all the lines go into have a ball bearing in it that can get jammed up?

[John_Kunkel]

A dry vacuum hose is no proof that it's not leaking into the booster. I'd pull the MC and visually check it.