Nah, just clean them.....

 

I'd probably check the float to see if its leaking and clean the sending unit.. You shouldn't have to adjust the float. Its not going to just lose its adjustment.

 

It's a resistive element with a contact arm that slides up-in-down across the element as the float moves in concert with the level of fuel. If the contact area is dirty at some point/points as it moves across the resistive element, it could give false readings no matter where it rides on the element. The float-arm itself may be moving up and down, but if the resistive element, or the contact arm is dirty.....may read anything.

No matter if it's bent, bruised or dirty....you're going to have to go in the tank to fix/replace it. I agree with Spanners on the bolts....I reuse them. Just don't damage or lose the funky little plastic washers.