X540 belt thrown

I purchased early 2000’s x540 with the 54” deck. Second time I used it and the belt came off. I discovered the tensioner pulley arm/double pulley has been monkeyed with. The sequence of washers and bushings were out of order. I have used the JD Parts diagrams to get everything back in order. The tensioner pulley is about 1 1/2” too high. I got a new arm ordered. The spring rubs on the lower deck drive pulley. This is the dumbest design I have ever seen. I have finally figured out how the parts go back in order. Someone has tried to fix this before I got it and now I have to learn the correct way to put it back together. Any help would be appreciated. Thanks

What serial number and which idler? There is two different 54" decks used on the X540. The latter one is one that I also had to modify slightly due to spring problem. That took some bending and lots of patience.

I attached some photos

The bearings were bad on the black arm of the double pulleys. I replaced those but that was not the issue.

I replaced the bushing washers and bolt and the C channel bracket that the tension pulley connects to. The tension pulley is way off the deck about 1 1/2”. That’s the issue. I don’t know if I am ordering parts for the right mower and it might be a different mower deck. I have not found any serial numbers on the deck

Here’s the mower serial number