i got a CJ7, had manual brakes; with scout axels(disc fronts/drum rear)...anyway i bought a new MC/dual diaphram/prop valve from BMB. needless to say it has been gravity bled for hours(even opened one bleeder at a time):mad3:...pressure bled SEVERAL TIMES:mad3::mad3:...needless to say,..i have Z E R O pressure....WTF am i doing wrong?? the only thing i can think is maybe i got sent a wrong valve?...maybe my MC rod isnt the right one...and the rod isnt long enough?....

PLEASE SHOOT ME SOME ADVICE...

anyway i bought a new MC/dual diaphram/prop valve from BMB.
Call BMB :idea:


How many times have you blead brakes?
if not many I'd guess you have air in the system.
Did you bench bleed the master cylinder?
Close up the system, and pump that pedal like crazy! A good 5-10 minutes, then check for fluid loss.

Did you bench bleed the master first ,you didn't mention it .If you didn't ,then you are nowhere already.

Your new rod is simply adjusted to have the pin or bolt sliding in through the clevis ,with the pedal at it up position ,if you did that ,then the rod is the correct length.The rod moves about 1 1/4 inches max ,if its doing that also ,then that is working correctly too.

If your new prop valve has a rubber plug on one end ,then push on the plug to recenter the valve inside ( that's the valve in "prop valve").

If you had to installed the master on to the booster before hanging it on the firewall ,double check that the rod lenght out of the booster matches the cavity depth in the master,and make sure that that little rod DOESN'T apply any pressure to the master in the off position ,or the brakes will drag with a little pressure ,overheat and seize.I'm assuming the rod is there to begin with they have fallen on the floor while I had my head turned before ( they can be sneaky).

Also make sure the brake hardlines at the master are going to the proper end ,the new master could be backwards from your original master ,there is no convention that dictates this ,so it needs to be verified sometimes.If it is backwards then not enough fluid volume goes to the front and the pedal goes to the floor.

I'm going over basics because I think you either missed one step or you have a bad master and the basics are how you will have to diagnose it anyway ,so get to your diag.

The dealer/manufacturer is going to make you do the basics also before they admit anything.

Also make sure your bleeder screw on the drum brakes is the highest point of wheel cylinder. If your rear axle is turned up for c/v style shaft, the bleeder screw is not the highest point. Air will remain in highest point. I chased the same problem on mine for a while till I discovered this. Either jack the rear, park on steep hill or do what I did and had to take the wheel cylinder off backing plate and bleed that way.

Also make sure your bleeder screw on the drum brakes is the highest point of wheel cylinder. If your rear axle is turned up for c/v style shaft, the bleeder screw is not the highest point. Air will remain in highest point. I chased the same problem on mine for a while till I discovered this. Either jack the rear, park on steep hill or do what I did and had to take the wheel cylinder off backing plate and bleed that way.

True, also make sure the calipers up front are the right side up. A buddy of mine just did this, easy mistake...

Thanks for all the help, will get after it monday,...Im sure i missed something. (this is my first time to do this, so it was easy for me to miss a step) but ill go over everything above. thanks again; ill let you kno how things go mon-or-tues.