Still don't see why that was necessary ...The ledger board holds up the end of the deck that’s against the house. If the ledger isn’t well fastened, the deck can simply fall off the house. A building inspector we talked with said the most common problem with DIY decks is ledger boards not properly fastened to the house. For a strong connection, a ledger needs 1/2-in. x 3-in. lag screws (or lag bolts if you have access from the inside to fasten the washers and nuts) driven every 16 in. This ledger board was fastened mostly with nails instead of lag screws (and no washers).
Starting at one end of the ledger board, drill two 1/4-in. pilot holes. Offset the holes so the top isn’t aligned with the bottom hole. Then drive the lag screws (with washers) using a drill and an impact socket (you’ll need a socket adapter that fits in your drill). Don’t countersink the screws—that only weakens the ledger board.
To me it looks like the post is bowed, that's why the corner is pulling apart. You are probably right that it cannot be corrected with just tension.
I thought maybe it was the propane tank pushing on it...Yes I think the bowed post is pushing the corner out, what's causing the post to be bowed? Ground movement? The deck itself has rarely been used.
The beam is not solid you want something under the corner with 2 postsI thought maybe it was the propane tank pushing on it...
But Neal is right, you do need to be careful how you proceed. Setting a temporary post under the beam next to it, and attaching it to the beam, would be prudent before attempting any work. No one should be on the deck until the repair is complete.
You could be right. I just looked again and I see that the deck boards are nailed, rather than screwed, into the joists, so the end joist/rim could need some support too if the post is removed.