My water temp and fuel guages have been intermittent and shaky since I got the car about 2 years ago.
The odometer quit so while I had the cluster out to replace the gears I took a look at the two trouble makers. Found that they just clip into the circuit board yet have a threaded shaft that sticks through the back of the cluster. The threaded shaft is part of the electrical circuit and there is a pad on the circuit board for it.
I cleaned up the contact pads and found two nuts and washers of appropriate size and locked the two guages down. So far not a jiggle out of either guage.
Also, while I had the cluster out, I spliced in two wires into the blue connector harness and added an additional low oil pressure light that lives next to the rear window defrost switch.
One of these days I'll install a proper oil pressure guage.
Hope this helps someone.