I am stumped I have an 86 mazda 323 and I can't get the brakes to work I replaced the master cylinder the rear brakes and cylinders the passenger front caliper and alot of bad brake line I bleed the brakes and can't get them to stiffen up if I pump the brakes really fast and they will stiffen up then when I release the brakes don't work again I can't see anywhere else where fluid maybe leaking any help thanks

 

Probably the proportioning valve but check the park brake cables.

 

i checked the parking brakes when I rebuilt the bake brakes they work good where is the proprtioning valve

 

Follow the brake lines from the master cylinder to the rear brakes. It should be on the firewall.

 

where can I get a new one or fix the old one thanks I looked online at advance auto but couldn't find one

 

You might be able to disasemble and clean it. I looked around and did not see one either.

 

took the valve apart and couldn't find anything wrong with it seems a little bit better bud still the same results

 

If you've used scrapyard or rebuilt components, that could be an issue. The other thing to check for air getting in between the reservoir and the master cylinder.

What you can do to test the brake components is to make a "stub", consisting of a short piece of brake line that you can couple to the car's lines, having a bleed nipple and flexible bleeding tube at the other end that you can immerse in your bleed jar.
Start by checking the master cylinder, disconnect the car's line and couple on the "stub".
Work your way through wheel by wheel until you find the feed which, when capped, cures your problem. Whatever lies downstream of test "stub" is the source of your problem.