Are they the original faces, or white faced ones?
The Knucklehead PO put white face gauged on mine, and the glue wasn't holding anymore, had the same problem, plus he didn't put the needle back on the fuel gauge properly, so the 1st week I had it I ran out of gas at 1/4 tank.
Take it all apart, use some clear Epoxy (bought at Advance Auto) to hold the faces on. I tried Super Glue type stuff, it let loose again in a couple of weeks.
Good luck.