I was having problems with my fuel sender in my Toyota Corolla so managed to get this green nut off by tapping it with soft sharp blows with a screw driver but now I cant get it the green ring back on as it seems to keep cross threading it only took one turn to get off before I could use hands and also when I took the float out it was worn at one edge and it appears there is a plastic bowl thing inside the tank where you can see the float has been rubbing against as its left black marks on the side of this bowl/tray that's inside the tank, Which I now think this has been stopping the float from moving freely and giving wrong fuel readings. 

 

I just wanted to ask what is the best way to get this stubborn green captive ring back on and if anyone here knows anything about this white plastic bowl/tray that's inside the tank as it appears to be moving around and feel that I am going to have the same problems. 

 

Just wondered if anyone knew anything about this plastic tray inside the tank as I haven't ever come across this kind of design, and more importantly if anyone knows the best way to get this ring back on as I seem to be putting it on straight and it turns with my hands for half a turn then its very difficult to move and looks like one side of the green ring is higher than the other, I have left this until tomorrow now but I certainly dont want to drive it as it is.

 

Wish id left the dame gauge issue now :( Thanks in advance everyone for any help.. 

I would remove the fuel feed and return pipes and slide the green ring away from the sender unit then try to screws the ring on to see if it goes on OK. Is it a multi start thread? Place the green ring level on the tank and turn it in the wrong direction until you feel the ring locate at the start of the threads then turn in the correct direction. Once you are confident with the way it goes on mark the ring with a marker pen to where the thread starts. Then replace the ring on the sender unit and hopefully it will go back on OK. Then replace the pipes. If you are trying to screw it on with the pipes attached it might be tilting the ring and cross threading. Also check the ring for damage to the threads.