Just bought a new to me 79', still sitting at my friends house due to brakes acting up.

Just replaced master cylinder with a new one from autozone, bled all four cornera, did bench bled the MC before install.

If I pump the pedal I get pressure but as soon as I let the pedal out pressure desapears. There is a valve under MC does any know what that is ? And what it does

Thanks in advance

 

Are there 3 lines coming out of the valve?

Change the vaccum line from the engine to the booster

 

2 lines to the valve from MC and 3 out.
The vaccum line is just for the booster isn't it

 

The little valve i think just splits the fluid front to rear.

The vaccum IS for the booster but it affects braking and pedal feel if theres a leak or no vaccum.

might need to bleed the brakes again

 

The engine is off...so pedal should be hard but like I said I can pump the pedal and get the pressure up.... am going to try and bleed the calipers again

 

Maybe the booster is bad?

 

The booster has no effect on brake hydraulic pressure.. I plan on deleting the booster anyway

 

So am just going to update this thread with the fix... I ended up getting a new master cylinder from autozone for the price of a rebuilt one ( don't ask me how). Flused and bled the system and my brakes came back.
$12 dollar fix