Brake problem (kinda long)

["basfe25" <dmcman73@xxxx>]

Hi all, here I go with a question on brakes. I just installed a new 
Brake Master Cylinder and bled out the lines (I bled the master 
also). Here is my problem. The rear brakes will lock up when the 
brake pedal is depressed but the front will not...they don't even 
look like they move. Here is the status on the systems: All calipers 
have been rebuilt with new seals and new stainless steel pistons. 
The front calipers had been split apart to clean then re-assembled 
with new inner seals (no leaks). The front brakes also have all new 
brake lines and the rear have some new ones. Before installing the 
master I turned out the nut on the rod that is connected to the 
booster (the rod that pushes the piston in the Master Brake when the 
pedal is depressed) just as instructed when I got the new master 
cylinder. I disconnected all the line in the front and re-checked 
them to make sure there were no blockages, all were clean. The 
system is also filled with Castrol GTLMA brake fluid (DOT 4). I've 
bled the brakes using my wife to press on the pedal while I opened 
the bleeders then release the pedal after I closed off the bleeders 
while I had a rubber hose in a jar of clean brake fluid. I've also 
tried "gravity" bleeding them and nothing seems to work. Like I said 
the rear work great but I can't get the front's to work at all!!

This is driving me crazy!! I bled the system a dozen times following 
the procedure in the workshop manual to no avail, I can only get the 
rear ones to lock. I don't have the engine running when I am doing 
this (to get a vacuum to the booster) since I don't believe this is 
needed to bleed the brakes. If I disconnect the line going into the 
master cylinder that feeds the front and shoot some compressed air 
into it I can the front calipers to lock...this tells me that the 
calipers are working and not frozen...am I right? I get fluid coming 
out of the bleeder screw when the system is all together also. I 
thought that it may have been a bad master and I exchanged it (the 
master cylinder is from a Delorean vendor, not aftermarket). I 
checked the brass "T" that connects the front right brake and the 
left front brake to the cylinder and it's good and clear from any 
debris. Has anyone run into this problem or am I the only one? Any 
suggestions? I've repaired and bled brakes on dozens of other cars 
with more complex systems in them (example: ABS with differentiating 
valves) and I have had no problems. The Delorean is one of the few 
cars I have seen with the most simplest brake system and I can't get 
the front brakes to work! ARRGGHH.

Thanks in advance,

Steve
3365