Brake Pressure, related to lines?

[doodles526]

My brake booster decided to die on me about a week ago. So i picked up a new one. This was the first time working with the brakes on my 260z, and i picked up some speed bleeders, they have worked really well for me in the past.

Anyways, replacing the booster was no problem. But i have run into a problem with bleeding that i dont know how to explain, or at least explain without going and replacing a bunch of other brake components.

I was able to bleed the front brakes just fine using the speed bleeders. But i have had issues with the back brakes. First off, when i tried to bleed the rear brakes, alot of rusty fluid came out, and then nothing came out, not even air, as if the line was clogged with rust or something, and i have no brake pressure. I traced my lines and checked connections for leaks, and checked if my bleeder had clogged and found nothing. And my the fluid levels in my master cylinder stay the same whenever i try to bleed the rear brakes. Im not an expert on automobiles, but am I going to have to replace my lines going to the rear brakes?

[lbpdz]

brakes are always fun..

If it were me, I would disconnect the hard lines at the back and front and try to blow air through them.. If you have rust though, there is a good chance your lines and wheel cylinders are shot. Time to unhook each of them and inspect..

When in doubt though, seek the advice of a professional. Brakes are too important to half a**

[John Coffey]

Below the master cylinder there's something called a "Brake Line Pressure Differential Switch" that will cut off pressure to either the front or rear brake circuit based on a pressure differential of 185 to 242 lb. per sq. in. The valve will shuttle towards the low pressure side cutting off any flow. Improper brake bleeding will throw this switch and cause the problem you're experiencing. Speed bleeders make it worse because of the spring pressure that keeps them closed.

You need to remove the speed bleeders and either gravity or vacuum bleed all the rear brake lines until you get fluid at both rear wheel cylinders. Then re-install the speed bleeders start your bleeding process.

[doodles526]

thanks john, You just saved me big bucks and alot of time