rear disc dont lock up like instructions say

[BaBiLuTH]

Hey guys, I have an 88 GT with a front and rear disc brake conversion from a 94
GT. The car stops fine. ( A little nose dive but this is kind of why I'm asking for help) I did the whole conversion 94 front spindle with 94 complete rear end with disc. I changed the master cyl (new) for a 94 unit. I changed the Booster(new) to a 94 unit. I converted to 2 port instead of 3, gutted the prop valve, and installed an adjustable prop valve. The instructions and the adjustable prop valve say that to set it, "turn the valve all the way to have FULL braking", then drive it until the rears lock up. It says that the front should lock up right before the rears do. My thing is that the rears dont lock up. Fronts lock only. Has anyone experienced this? Also, the car stops perfect but I get nose dive because I think that the rears aren't performing 100%. Someone please help me get these things working right. Thanks!!

 

[Mustang5L5]

Did you bleed the brakes with the valve turned in all the way before you started backing it out??

 

[BaBiLuTH]

I dont remember if the valve was in or out, but it was so the rears have the most pressure that they can get. Also, I jacked up the rear and ran the car with the rear wheels off the ground and the rears stop, but just not good enough when they're on the floor.

 

[Mustang5L5]

How does your pedal feel???

 

[BaBiLuTH]

Its got a lil bit of play at the top...maybe like an inch..other than that good...maybe a TAD spongy i guess

 

[Mustang5L5]

I wanna say there is still some air in the lines, but i don't want to make you rebleed the brakes for nothing.

Either way that would be the first thing i would try. I would turn the prop valve all the way to MAX brake pressure and rebleed all 4 wheels again. A rubber mallet to tap on the calipers and speed bleeders would help you out here.

 

[BaBiLuTH]

So basically the rear are supposed to be able to lock up if I wanted them to right?

 

[jrichker]

I have TC disks in the rear, and when they are properly adjusted, they will lock up.