If you are talking about the anchor pin right above the wheel cylinder, (and that's what it sounds like), you have a thick washer with the center hole having a flats on two sides. This washer goes on the OUTSIDE of the backing plate. If you try to install this washer on the inside, the anchor pin flats I don't think will reach the backing plate, which allows it to turn, which you don't want. Once you install the anchor pin, there is enough shaft that comes through the backing plate for the washer to slide upon.
I always do one side at a time, start to finish. That way, when the mind slips (and I hope I'm not alone on this mind slipping deal), I have a template on the other side to go by.
Mike
