I got a 70 or 71 chevelle disc brake setup including the booster, master cylinder equalization distribution block and something else that i can't identify. It is a part that mounts on the right bolt that holds the master cylinder to the booster. It has a line that comes into the center of one end from the front brake reservoir and a line that comes out of the top of it and runs down to the equalization/distribution block.

It is about 2 1/2" long and about 1 1/2" in diameter. What is this thing and is it really necessary? Could it be eliminated since we have a distribution block and equalization valve. Is this thing a 1970 widget that is no longer employed in braking systems.

Any help will be greately appreciated?

Clyde

Clyde,
There should be a button/plunger on one end of it. If so, I believe this part is a metering valve. This turns the red light on when one of the brake systems fails. Hope this helps.
Jon

That "golf ball " is probably your metering valve. It reduces the pressure to the rear brakes to avoid premature lockup. You need this because the distribution block does not have that feature. The distribution block on later cars includes some extra valving and got re-named "combination valve".

Yes, it does have the button on the back. It is plumbed into the front brake line before the distribution block. It doesn't connect into the back brakes at all. The distibution block does have a screw in the middle of the valve body which acts like a pressure limitting valve between the front and back brake lines.

So if its not connected to the rear brakes, is it a necessary part?

I dug out my '70 GM Chassis Service Manual and it states "On models with disc brakes, the front brake hydraulic line is routed through a pressure metering valve(the one your talking about). The valve controls the hydraulic pressure to the front brakes resulting in the correct pressure balance between the front and rear...." My opinion, I am not an expert, would be if you are running discs on the front than this valve is needed.