dkmlrm

I had to replace the master cylinder on my 1992 Explorer.

I am having difficulty getting fluid to the rear drums. I believe it is being stopped at the ABS modulator valve. According to my Haynes Manual there is supposed to be a bleed port near the top of the valve.

I can find a large nut ( 7/6 inch wrench ) with a rubber cap on a knob protruding from the nut. While loosening the nut it feels as if there was
spring tension behind it. I was afraid to turn it more than one turn.

Is this the bleed port ?

Can I bleed the ABS valve at the input and output ports only ?

The front brakes bleed fine.

Thanks