69cj brake warning light on

Hi all, I have a 69 cj with power front disk brakes I'm having fun with. I have no front brakes and the warning light up. Work so far...new master cylinder (bench bled before install) with the push-rod adjusted correctly. Distribution block and rear proportioning valve stripped, cleaned, new seal kits fitted, bench tested ok and re-installed . Vaccum booster tested ok, new check valve instaled. Rear slave cylinders, lines and drum brake pads replaced and adjusted (speed bleeders fitted), front calipers rebuilt, new pads and russell braided lines fitted.
No matter what I do after pedal bleeding the system, I can't get the valve in the distribution block to centre after the rebuild. I have left the rear bleeders cracked and pumped the pedal to try to boost front line pressure to pop it back to no avail. With engine off I have a reasonably firm pedal, with it running it almost goes to the floor, Booster checks out ok.

Apart from grinding down a bolt to jam into the warning sensor fitting to lock the valve in position and then bleeding/equalising the front and rear pressure in the lines, is there anything else that could be causing this symptom as at the moment all I can think is that there has to be a lot of air in the front lines that will not come out with pedal bleeding only even though I've bled about a litre through either side so far.

Stephen  

We used to take the switch out and install a tool to keep the valve centered during hydraulic repairs. How you keep it centered is up to you but if it isn't you'll get the symptoms noted.jlg  

After doing a complete brake rebuild on my 66 coupe I really struggled to get the air out of the front system. The solution was a hand operated vacuum pump bleeder. It connects to the caliper and draws fluid through the system. I think I got mine at NAPA. I had never tried this method before, now I would never do anything else. Good luck.