mine doesn't look like this but here is a new one for $60
https://www.ebay.com/itm/NEW-1984-1991-Toyota-4Runner-Pickup-Rear-Brake-Load-Balance-Sensing-Valve/142655049879?fits=Model%3APickup%7CMake%3AToyota&hash=item2136e75097:g:Fy0AAOSwpspbdavX
here is the one I bought
rear brake valve