Is this on an in ground or above ground pool?
Be sure your plugs in the housing are in securely and have either orings or teflon tape on them to prevent water from being sucked in. Also, inspect your lid cover o ring as well.
You should be releasing the air at your filter and not the pump. Some filters (sand) do not have an air release and the air has to work through the system.
Sometimes, the water is completely full in the basket with no air and it looks like it is empty, but there is water flow in the pool which means it is full.
If no water is coming into the pump basket then either air is coming in from the hoses (above ground pool) or where the pipe attaches to the front of the pump (male adapter has loosened).
Also, be sure that all plugs are removed from the wall fittings and skimmer after winterizing.
I would try the above before taking apart the pump to check the impeller. If the impeller is broken or clogged it cannot create the low needed to bring water into the system. If the filter is not full of water yet it would take a few minutes to prime but you should see some water entering the system.
Let me know if above or in ground and I can help further.