MGB 1980 MGB No rear brakes after replacing MC & booster

I replaced the Master and the booster last weekend on my '80 MGB.
The front brakes bleeding went great, no trouble at all.
The rears - nothing. No fluid comes out when the bleeder is opened.
I'm pretty sure others have experienced something like this so what am I doing wrong?

Possible problems:
I did not bench bleed the MC.
All I did with the PDWA was remove it from the old MC and install it in the new one.
I didn't know about adjusting the rear brakes until they were locked up before bleeding so I didn't do that.

Next time I get under there, this weekend, I'll adjust the back so the wheels lock up before I try to bleed them.
Anyone got any great ideas I'd really like to hear them.

You need to bench bleed the master.
That said, you can do it on the car now that you are installed.
Rags, water handy....and two people.
Have your assistant pump up the master, then open the pipe for rear brakes at the master, see if you have any fluid or air spitting.
Close, do it again.
If you get fluid under pressure after a half dozen strokes, now you can bleed back.
If not, pull the master and bench it. I have those little plastic fittings and nylon pipes to bleed back into the reservoir.
Reason for rags and water....if DOT3 or 4, brake fluid will eat paint...and water will neutralize it. Flush it all off.

PDA....is 1980 one of those that shifts the shuttle full over and blocks the dead side?

If so, you may need to centre the shuttle.

On my '76 there was a proportioning valve / switch on the drivers inner fender wall. The directions I have seen require you to back out the electrical switch 3 1/2 turns from that device to allow fluid to move to the rear. Not sure on the newer cars but worth a look. S/B covered in the shop manual.

TOC is right. Check you tube , maybe John Twist has a video on it.

How old are the rubber lines? My front ones collapsed once and locked up the front brakes.

None of the above, but thanks for trying. :wink-new:

I bought a vacuum bleeder from HF and this morning got out there and used it.
Now my brakes are awesome!!