Gas Gage Stuck?

[lindajane]

Hi,

I just had a major service and new brakes. My gas gage seemed to jump
after it reached a quarter tank, but due to cost I told him to forget it.
He said he have to take out and clean etc. Since I got the car back,
it runs great, but the gas gage is on reserve, and I put Plenty of fuel in.
It's disconcerting, Is there any way, if I lift the hood, that I may fix
this?
Thanks
L