Mk2 Escort rear disc brake conversion

[S47]

I'm baffled
Just changed/upgraded the rear drum brakes on my Ford escort 'English' axle for Sierra Cosworth rear disc brake calipers and Fiesta Mk2 Discs, Fitting was no problem, but bleeding did take awhile.
I also fitted a new Standard Master Cylinder, and all new pipework including S/S flexihoses.
My problem is that with full pedal travel I have no brakes??
It takes about 1 1/2 times the full pedal travel to get any brakes??
Then If I keep the pedal depressed I get solid brakes until I release pedal - the pedal doesn't go down any further once I get pedal pressure, which suggests to me there's no air in system.
New Handbrake via the Sierra cable works fine.
Any Idea's or suggestions how to cure this??
TA

[TallPaul]

I'm a bit late to this but could it be that the rear calipers need more fluid to move them than the old drum brake cylinders? May need a different master cylinder with more suitable bore ratio.

[mark beavan]

Have you changed the standard master cylinder and pedal box? Most people fit what is known as a "bias pedal box" when fitting rear discs, which will give you two master cylinders. One for the front and one for the rear, and the ability to adjust the amount of front/rear bias on the brakes.
If you don't fit one of these, you will need to fit some form of valve in the hydraulic line to the rear brakes to reduce the amount of pressure going to them, or you will suffer from premature locking of the rear brakes exactly when you don't want it.