PacFab FNS 36 DE Filter Automatic Air Relief Valve leaking water

I have an older vinyl liner pool with this filter and the air relief valve is leaking. I have a couple concerns:

Is there any repair of this valve?
Does the valve screw onto the filter top housing?
I cannot find a replacement that looks like the one that is on the filter, are there generic or substitute replacements?

Thanks for any help,

David

Is this your filter http://www.pentairpool.com/partslist...ilters-68.htm#?
Is this the part you need Pentair 273550 Manual Air Relief Assembly ?

If you buy it through this link the PoolForum gets some coin to keep the lights on.

That appears to be the filter but the air relief valve in the filter diagram looks like my valve, but the Pentair 273550 looks similar but it does not have a port on the top that automatically relieves air without having to open the manual port. Is that feature not needed?

When my filter stops, it is on a timer, the filter drains back to the pool as the port on the top of the air relief valve not only allows air to escape the filter but to allow air to return to the filter and the water to drain out. When the filter comes back on the air automatically escapes through this port on top and when water fills the filter this port automatically shuts off, except it is now leaking water not quite a stream but a very fast drip. The float inside the valve must not be sealing properly.

Does this assembly unscrew from the filter housing? There is a screen on the inside of the filter housing that covers the input side of the valve, I do not see a nut or anything except this screen piece on the inside. I gave it a fairly hard turn and it did not move, but I did not use a wrench just my hand holding the valve and top of the filter housing.

Thanks for any information you can supply,

David