I just installed new Dexter self adjusting brakes on all four wheels. They do adjust both in forward and backward braking.
To make the initial adjustment after installing them, I pulled the emergency brake cable, and then by hand rocked the wheels back and forth. Each time they were rocked to the end of their travel there was a click as the adjuster moved the star wheel. After awhile there was no more clicks, and the brakes were properly adjusted.
Followed Dexter's instructions on breaking them in. Took about about 50 miles of driving to get the shoes well seated; after that, the brakes worked perfect.
Regards,
Doug