I have installed a power booster on the drum/drum brakes in my 67 Camaro. I have replaced the master cylinder with a new one that came together with a booster. It doesn’t seem to work very well. The brake pedal seem to travel far before the car starts braking, and when you press on the brakes there is a “huge sucking sound”. As far as I remember from my past experiences with the power brakes, they have to engage right away.

I have bled all of the wheels, but I did not bench bled the master cylinder. I read about bench bleeding the cylinder after I already installed it.

So, my questions are: Do I really need to bench bleed the MC, do you think it will make a difference? And do I need to install the distributor that went below the old MC. Right now I have the break lines go directly to the new MC.

Thank you, Len

bench bled it or chances are you will never get all the air out!

I would bench bleed the MC. Also I would install the disturbution block. Also make sure your rod lenght is correct. If I remember correctly i read on here someware that there are two holes in the brake pedal. If so make sure you are in the right hole.Try doing a search of the site there are numerous posts on break problems and bleeding them.

hhmmm i seen in your post a hugh sucking sound? the booster is no good than.

If you have a low pedal, there will be more air sucked in the passenger side of the booster.
Try bleeding the lines at the master cyl.
Did you connect the pushrod to the lower hole on the brake pedal?
David

hhmmm i seen in your post a hugh sucking sound? the booster is no good than.

Heretis67,

Thank you for your reply. How do I tell if my booster is good or not? I purchased it together with the MC.

If you have a low pedal, there will be more air sucked in the passenger side of the booster.
Try bleeding the lines at the master cyl.
Did you connect the pushrod to the lower hole on the brake pedal?
David

David,

Thank you for your reply. I did connect the pushrod to the lower hole on the brake pedal. What do you mean "Try bleeding the lines at the MC", and do I need to level the MC first?

Regards, Len

David,

Thank you for your reply. I did connect the pushrod to the lower hole on the brake pedal. What do you mean "Try bleeding the lines at the MC", and do I need to level the MC first?

Regards, Len

it just about impossible to level the master while it bolted in place, the ass end of the car would have to be about 6 feet in the air!
take it off and bench bleed it.

if you just push petal like a 2 inches or less it hisses it is bad.

Back off one line at the master cyl, press the pedal, tighten the line, - repeat. Catch the brake fluid that comes out or it will make a mess.

Also verify that the pushrod from booster to master cyl is the correct length. There are two lengths of rod, and two depths of master cyls, a short and a deep hole. If you have the short rod and deep hole master, you will have excessive pedal travel.
David