The plastic on these old gauges is incredibly brittle. I put the strength at just slightly stronger than a ginger cookie. You've been warned.
I posted earlier that all indication were that my gauge which had been attached to ground and operated for who knows how long was not moving. The shop swears they didn't do it so I guess it was a mouse or a vandal.
I checked the gauge and it moved when 12v was put through it but not when the sender was in the circuit. My ohm meter indicated that the resistance was a little low (45 ohms) but when I checked the current through it the resistance was closer to speck. It measured 50 ohms spec is 55.
To me this indicated that something in the gauge is distorted and that is why it doesn't read. Probably from being heated and forced to bend too much by having a full 12v across it for to long.
Looking at the bimetal part I judged the bimetal strip to bent in the middle of the heating wire.
With the brittleness of the plastic, and the delicacy of the insulation in mind I used a soft plastic rod to hold the center of the wrapped portion of the bimetal strip and straightened it out until the pivot pin and the bimetal pin lined up pointing at the bottom of the stripes on the gauge.
I cleaned up the finger prints, fabricated a replacement for the little white plastic thing that hold the gauge down. The original part somehow disappeared while trying to reinstall it.
It works fine but reads a little higher so I probably should have aimed a little below the painted stripes on the gauge.
That $70 dollars saved. Maybe we stop throwing out gauges that can be fixed given they are in very short supply.
I posted earlier that all indication were that my gauge which had been attached to ground and operated for who knows how long was not moving. The shop swears they didn't do it so I guess it was a mouse or a vandal.
I checked the gauge and it moved when 12v was put through it but not when the sender was in the circuit. My ohm meter indicated that the resistance was a little low (45 ohms) but when I checked the current through it the resistance was closer to speck. It measured 50 ohms spec is 55.
To me this indicated that something in the gauge is distorted and that is why it doesn't read. Probably from being heated and forced to bend too much by having a full 12v across it for to long.
Looking at the bimetal part I judged the bimetal strip to bent in the middle of the heating wire.
With the brittleness of the plastic, and the delicacy of the insulation in mind I used a soft plastic rod to hold the center of the wrapped portion of the bimetal strip and straightened it out until the pivot pin and the bimetal pin lined up pointing at the bottom of the stripes on the gauge.
I cleaned up the finger prints, fabricated a replacement for the little white plastic thing that hold the gauge down. The original part somehow disappeared while trying to reinstall it.
It works fine but reads a little higher so I probably should have aimed a little below the painted stripes on the gauge.
That $70 dollars saved. Maybe we stop throwing out gauges that can be fixed given they are in very short supply.
