I finally removed the Gauge Cluster on my 1975 Bobcat wagon and what a mess! The previous owner's 16 year old had duct taped the backing on, along with liberal amounts of clear silicone glue... add to that a little tinfoil (?)... Please see pics... My original is on top, the71-73 on bottom...

I had a similar problem with the flex circuit board falling apart, dim lights, flaky connector plug and flaky fuel gauge readings and I see that this seems to be a common problem as the flex circuit connectio s deterriorate.

I solved the problem by removing the flex circuit board and just rewiring the instrument panel. At first i didnt have a diagram with color codes so i traced the wires. There is a link to a wiring diagram elsewhere here with color codes that makes the job a lot easier.

I replaced the connector to the wiring harness with a much more reliable 9 pin connector and a 4 pin connector.  I also extended the pigtail that I attached to the cluster so that I can remove and replace the cluster with the wiring connected.

I as well dismantled the cluster and lined the dash light areas with aluminum foil to reflect more light into the gauges, replaced the bulbs with led lights, added an extra led to a dark space and added an adjustable electronic regulator which made the gas gauge reliable. I also calibrated the fuel gauge by adjusting the voltage regulator so now my gas gauge is accurate at 1/4, 1/2, and full tank.

Now i have bright lights just like the new cars and a reliable gas gauge.

I did this incrementally over several months but figure that it could be done in probably 3-4 hours if you have info about how to do it.

I got the colored wire from an old, non functional computer power supply that you can probably get from the repair guys at a computer store

I will make some pic of my mods and post them with instructions and a source for the multipin connectors and voltage regulator parts as soon as i have some time