Bleeding rear brakes on a disc brake Dart 1972

[Johnny Dart]

I'm having a bit of bother bleeding the rear brakes, I can get little to no brake fluid with my vac brake bleeder.
I think it may be something to do with the brake valve on the n/s/f chassis leg.
Is there something that needs to be reset, it's like the valve has blocked off fluid to the rear brakes, like it would with rear brake failure.
Any ideas .
Thanks
Johnny

[Pete]

Let it gravity bleed, open the nipples and go and have a cuppa....

... having said that, I had a rear hose collapse on my '71 Barracuda and even running the motor with a power booster and the rear drums off would not permit the fluid to come out..... a nice "gotcha!" worth checking....

[Johnny Dart]

It's got a Dana 44hd axle with disc brakes, the 2 rear hoses were new, so should be OK but I will check.
I seem to remember years ago someone on here was saying that the brake valve in my picture was fitted to cut off fluid to the rear or front brakes , if there was a circuit failure.
I just don't remember what was said about it.
Or how to reset it

[mygasser]

i've 'reset' them by removing and bypassing them a few times.
is your master cylinder a disc/disc one? if not you may need one that is, or at least an adjustable proportioning valve for the rear line.
neil.

[Johnny Dart]

Yes indeed, I had thought of removing it and I probably will need a adjustable limiting thingy.
Master cylinder is a disc drum one.
I'd just like to get it back working . I've taken the switch off , and had a look inside, but it's not what I was expecting, no shuttle that I could see to move back into possition.
It the moment, after more bleeding , and not really getting much out , I have no back brakes , but good front brakes

[Johnny Dart]

After some Google and you tube research, I found that there is a shuttle valve inside the combination/proportioning valve.
I managed to get it back in position , by bleeding the front brakes first, and then the back. The Vac bleeder did not get on with bleeding the brakes where there was a combination valve involved. It had to be pedal pressing method.
There is a tool that locks the shuttle for bleeding .I bought one , but its not arrived yet
Ok for next time.

[Johnny Dart]

I also found the boots had split, on the caliper pistons, they were siezed up too.
I fitted new ones.
Here's a pic of the combination valve.