So the previous owner of my gauges cut them all out of another car. So the water temp gauge seems to have a permanently mounted sender. Is there a way to replace it or am I out of luck and just buy another?
If there are no wires then it has a capillary tube. Basically a mechanical gauge. And you are stuck with it.
HI Purple . Sounds like the Cappilary tube & bulb is gone . A cap-tube & bulb can be replaced , but it will cost you some $$. All early Curved gl*** SWgauges are worth fixin`. Big logo and back , like "Wings" gauges , 2 5\8" Smooth-bezels or the back-mount ( Auburn-style ) gauges. Sixties temp gauges are easier to find, so it would probably be cheaper to replace than repair. Klaz
If your "permanent sender" looks like this, stick the bulb end in a pan of hot water on the stove and see if it works. This is a mechanical temp gauge. You may or may not have the fitting that this fits into on the block. It's not shown here. That collar up on the tube slides down and screws into the missing fitting holding the bulb in place. The fittings are readily available. I prefer these over electrical gauges.
Here is a place that repairs/replaces barret tubes on temp. gauges. i have used them several times and the price is reasonable ($75-$100) and the turn around is good (2-3 weeks). MOMA Margret Lucas 1321 2nd st. NW, Albq. NM 87102. (505) 766-6661. They can make the tube any length you want.
Seems to me, there was a tech on replacing the capillary and bulb not that long ago. While I haven't tried it myself, it didn't seem to be to difficult to do. I whole idea was to get a new (cheap) gauge and use the cap and bulb with the gas charge in it as a replacement. If I remember right, you place the bulb and as much as the capillary as you can in ice water. This keeps the gas charge as a liquid, and not boil and vent off when you open up the line. Have the SW gauge capillary out, (desoldered) and the area cleaned up and ready to resolder. Set that aside. On the new donar gauge. sand down the capillary tube for three inches or so, this is where your going to make your cut. Now remove the capillary tube from the new gauge, close to the gauge head. To do this, use a three corner file, give it a stoke with the file at three spaced out spots around the tube. This "scores" the tube enough to snap it clean and not crush it in, which would close it off. Don't let the open end drop in the water, and get it into the SW gauge and soldered as quickly as possible, (DON'T use an open flame, soldering gun or iron only) you only get one shot at this. Solder up the joint and test it by putting the bulb in a pot of boiling water. If you did it without losing any gas, it should read 212 F. Try a search on "gauge repair", it was a little more in depth, you might be able to save the gauge.
As klazurfers says, these capillary tube gauges can be restored. Back in the day these kind of tubes contained mercury/quicksilver. The liquid metal will expande during heating and move the gauge face needle. This technology for reading temperature is readily available also today for industrial appliances. I have bought A LOT at my previous jobb. We used them as a mechanical back up for resistance temperature detectors, reading bearing temp on Hydro Power Generetors. Modern ones usualy contains nitrogen gas due to the environmental issues of mercury. If you search for a producer of such instruments you may be lucky and get help restoring yours. Some regular gauge restorer firm may also know how/where to get this done. I say, fix the old one. Good Luck Paul
repair techs and pages. http://www.jalopyjournal.com/forum/showthread.php?t=190195&highlight=gauge+repair http://www.ply33.com/Repair/tempgauge
From what I can tell from the backside of your gauge, it looks like a Stewart Warner Standard Series. A new mechanical water temp can be bought from Speedway Motors for $35. Show us the face to verify it's not some obscure, rare piece.